LinuxPPS (RESUBMIT 2): the PPS Linux implementation. - Kernel

This is a discussion on LinuxPPS (RESUBMIT 2): the PPS Linux implementation. - Kernel ; This patch set adds the PPS support into Linux. PPS means "pulse per second" and its API is specified by RFC 2783 (Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0). The code has been tested with the NTPD program ( ...

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Thread: LinuxPPS (RESUBMIT 2): the PPS Linux implementation.

  1. LinuxPPS (RESUBMIT 2): the PPS Linux implementation.

    This patch set adds the PPS support into Linux.

    PPS means "pulse per second" and its API is specified by RFC 2783
    (Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0).

    The code has been tested with the NTPD program
    (http://www.eecis.udel.edu/~mills/ntp/html/index.html) and several GPS
    antennae.

    Rodolfo

    --

    Documentation/pps/Makefile | 2
    b/Documentation/ABI/testing/sysfs-pps | 73 +++++++
    b/Documentation/ioctl-number.txt | 2
    b/Documentation/pps/Makefile | 27 ++
    b/Documentation/pps/pps.txt | 170 ++++++++++++++++
    b/Documentation/pps/ppsctl.c | 63 ++++++
    b/Documentation/pps/ppsfind | 17 +
    b/Documentation/pps/ppstest.c | 152 +++++++++++++++
    b/Documentation/pps/timepps.h | 196 +++++++++++++++++++
    b/MAINTAINERS | 7
    b/drivers/Kconfig | 2
    b/drivers/Makefile | 1
    b/drivers/char/lp.c | 61 ++++++
    b/drivers/pps/Kconfig | 33 +++
    b/drivers/pps/Makefile | 8
    b/drivers/pps/clients/Kconfig | 18 +
    b/drivers/pps/clients/Makefile | 9
    b/drivers/pps/clients/ktimer.c | 115 +++++++++++
    b/drivers/pps/kapi.c | 272 +++++++++++++++++++++++++++
    b/drivers/pps/pps.c | 342 ++++++++++++++++++++++++++++++++++
    b/drivers/pps/sysfs.c | 130 ++++++++++++
    b/drivers/serial/8250.c | 2
    b/drivers/serial/serial_core.c | 71 ++++++-
    b/include/linux/Kbuild | 1
    b/include/linux/parport.h | 13 +
    b/include/linux/pps.h | 205 ++++++++++++++++++++
    b/include/linux/serial_core.h | 31 ++-
    drivers/pps/Kconfig | 2
    drivers/pps/Makefile | 1
    drivers/pps/clients/Kconfig | 20 +
    30 files changed, 2031 insertions(+), 15 deletions(-)


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  2. [PATCH 4/7] PPS: LinuxPPS clients support.

    Each PPS source can be registered/deregistered into the system by
    using special modules called "clients". They simply define the PPS
    sources' attributes and implement the time signal registartion
    mechanism.

    This patch adds a special directory for such clients and adds a dummy
    client that can be useful to test system integrity on real systems.

    Signed-off-by: Rodolfo Giometti
    ---
    drivers/pps/Kconfig | 2 +
    drivers/pps/Makefile | 1 +
    drivers/pps/clients/Kconfig | 18 +++++++
    drivers/pps/clients/Makefile | 9 +++
    drivers/pps/clients/ktimer.c | 114 ++++++++++++++++++++++++++++++++++++++++++
    5 files changed, 144 insertions(+), 0 deletions(-)
    create mode 100644 drivers/pps/clients/Kconfig
    create mode 100644 drivers/pps/clients/Makefile
    create mode 100644 drivers/pps/clients/ktimer.c

    diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig
    index cc2eb8e..1afe4e0 100644
    --- a/drivers/pps/Kconfig
    +++ b/drivers/pps/Kconfig
    @@ -30,4 +30,6 @@ config PPS_DEBUG
    messages to the system log. Select this if you are having a
    problem with PPS support and want to see more of what is going on.

    +source drivers/pps/clients/Kconfig
    +
    endmenu
    diff --git a/drivers/pps/Makefile b/drivers/pps/Makefile
    index 19ea582..98960dd 100644
    --- a/drivers/pps/Makefile
    +++ b/drivers/pps/Makefile
    @@ -4,5 +4,6 @@

    pps_core-y := pps.o kapi.o sysfs.o
    obj-$(CONFIG_PPS) := pps_core.o
    +obj-y += clients/

    ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG
    diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
    new file mode 100644
    index 0000000..60b83be
    --- /dev/null
    +++ b/drivers/pps/clients/Kconfig
    @@ -0,0 +1,18 @@
    +#
    +# PPS clients configuration
    +#
    +
    +if PPS
    +
    +comment "PPS clients support"
    +
    +config PPS_CLIENT_KTIMER
    + tristate "Kernel timer client (Testing client, use for debug)"
    + help
    + If you say yes here you get support for a PPS debugging client
    + which uses a kernel timer to generate the PPS signal.
    +
    + This driver can also be built as a module. If so, the module
    + will be called ktimer.ko.
    +
    +endif
    diff --git a/drivers/pps/clients/Makefile b/drivers/pps/clients/Makefile
    new file mode 100644
    index 0000000..f3c1e39
    --- /dev/null
    +++ b/drivers/pps/clients/Makefile
    @@ -0,0 +1,9 @@
    +#
    +# Makefile for PPS clients.
    +#
    +
    +obj-$(CONFIG_PPS_CLIENT_KTIMER) += ktimer.o
    +
    +ifeq ($(CONFIG_PPS_DEBUG),y)
    +EXTRA_CFLAGS += -DDEBUG
    +endif
    diff --git a/drivers/pps/clients/ktimer.c b/drivers/pps/clients/ktimer.c
    new file mode 100644
    index 0000000..5845188
    --- /dev/null
    +++ b/drivers/pps/clients/ktimer.c
    @@ -0,0 +1,114 @@
    +/*
    + * ktimer.c -- kernel timer test client
    + *
    + *
    + * Copyright (C) 2005-2006 Rodolfo Giometti
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    + */
    +
    +
    +#include
    +#include
    +#include
    +#include
    +#include
    +
    +#include
    +
    +/*
    + * Global variables
    + */
    +
    +static int source;
    +static struct timer_list ktimer;
    +
    +/*
    + * The kernel timer
    + */
    +
    +static void pps_ktimer_event(unsigned long ptr)
    +{
    + pr_info("PPS event at %lu\n", jiffies);
    +
    + pps_event(source, PPS_CAPTUREASSERT, NULL);
    +
    + mod_timer(&ktimer, jiffies + HZ);
    +}
    +
    +/*
    + * The echo function
    + */
    +
    +static void pps_ktimer_echo(int source, int event, void *data)
    +{
    + pr_info("echo %s %s for source %d\n",
    + event & PPS_CAPTUREASSERT ? "assert" : "",
    + event & PPS_CAPTURECLEAR ? "clear" : "",
    + source);
    +}
    +
    +/*
    + * The PPS info struct
    + */
    +
    +static struct pps_source_info pps_ktimer_info = {
    + .name = "ktimer",
    + .path = "",
    + .mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT | \
    + PPS_ECHOASSERT | \
    + PPS_CANWAIT | PPS_TSFMT_TSPEC,
    + .echo = pps_ktimer_echo,
    + .owner = THIS_MODULE,
    +};
    +
    +/*
    + * Module staff
    + */
    +
    +static void __exit pps_ktimer_exit(void)
    +{
    + del_timer_sync(&ktimer);
    + pps_unregister_source(source);
    +
    + pr_info("ktimer PPS source unregistered\n");
    +}
    +
    +static int __init pps_ktimer_init(void)
    +{
    + int ret;
    +
    + ret = pps_register_source(&pps_ktimer_info,
    + PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
    + if (ret < 0) {
    + printk(KERN_ERR "cannot register ktimer source\n");
    + return ret;
    + }
    + source = ret;
    +
    + setup_timer(&ktimer, pps_ktimer_event, 0);
    + mod_timer(&ktimer, jiffies + HZ);
    +
    + pr_info("ktimer PPS source registered at %d\n", source);
    +
    + return 0;
    +}
    +
    +module_init(pps_ktimer_init);
    +module_exit(pps_ktimer_exit);
    +
    +MODULE_AUTHOR("Rodolfo Giometti ");
    +MODULE_DESCRIPTION("dummy PPS source by using a kernel timer (just for debug)");
    +MODULE_LICENSE("GPL");
    --
    1.5.2.5

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  3. [PATCH 2/7] PPS: userland header file for PPS API.

    This patch adds into the PPS's documentation directory a possible
    implementation of the PPS API (RFC 2783) by using the LinuxPPS's char
    devices.

    This file is not just an example but it can be used into real
    systems.

    Signed-off-by: Rodolfo Giometti
    ---
    Documentation/pps/timepps.h | 195 +++++++++++++++++++++++++++++++++++++++++++
    1 files changed, 195 insertions(+), 0 deletions(-)
    create mode 100644 Documentation/pps/timepps.h

    diff --git a/Documentation/pps/timepps.h b/Documentation/pps/timepps.h
    new file mode 100644
    index 0000000..2372949
    --- /dev/null
    +++ b/Documentation/pps/timepps.h
    @@ -0,0 +1,195 @@
    +/*
    + * timepps.h -- PPS API main header
    + *
    + * Copyright (C) 2005-2007 Rodolfo Giometti
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    + */
    +
    +#ifndef _SYS_TIMEPPS_H_
    +#define _SYS_TIMEPPS_H_
    +
    +#include
    +#include
    +#include
    +#include
    +
    +#define LINUXPPS 1 /* signal we are using LinuxPPS */
    +
    +/*
    + * New data structures
    + */
    +
    +struct ntp_fp {
    + unsigned int integral;
    + unsigned int fractional;
    +};
    +
    +union pps_timeu {
    + struct timespec tspec;
    + struct ntp_fp ntpfp;
    + unsigned long longpad[3];
    +};
    +
    +struct pps_info {
    + unsigned long assert_sequence; /* seq. num. of assert event */
    + unsigned long clear_sequence; /* seq. num. of clear event */
    + union pps_timeu assert_tu; /* time of assert event */
    + union pps_timeu clear_tu; /* time of clear event */
    + int current_mode; /* current mode bits */
    +};
    +
    +struct pps_params {
    + int api_version; /* API version # */
    + int mode; /* mode bits */
    + union pps_timeu assert_off_tu; /* offset compensation for assert */
    + union pps_timeu clear_off_tu; /* offset compensation for clear */
    +};
    +
    +typedef int pps_handle_t; /* represents a PPS source */
    +typedef unsigned long pps_seq_t; /* sequence number */
    +typedef struct ntp_fp ntp_fp_t; /* NTP-compatible time stamp */
    +typedef union pps_timeu pps_timeu_t; /* generic data type for time stamps */
    +typedef struct pps_info pps_info_t;
    +typedef struct pps_params pps_params_t;
    +
    +#define assert_timestamp assert_tu.tspec
    +#define clear_timestamp clear_tu.tspec
    +
    +#define assert_timestamp_ntpfp assert_tu.ntpfp
    +#define clear_timestamp_ntpfp clear_tu.ntpfp
    +
    +#define assert_offset assert_off_tu.tspec
    +#define clear_offset clear_off_tu.tspec
    +
    +#define assert_offset_ntpfp assert_off_tu.ntpfp
    +#define clear_offset_ntpfp clear_off_tu.ntpfp
    +
    +/*
    + * The PPS API
    + */
    +
    +static __inline int time_pps_create(int source, pps_handle_t *handle)
    +{
    + int ret;
    +
    + if (!handle) {
    + errno = EINVAL;
    + return -1;
    + }
    +
    + /* First we check if current device is a PPS valid PPS one...
    + */
    + ret = ioctl(source, PPS_CHECK);
    + if (ret) {
    + errno = EOPNOTSUPP;
    + return -1;
    + }
    +
    + /* ... then since in LinuxPPS there are no differences between a
    + * "PPS source" and a "PPS handle", we simply return the same value.
    + */
    + *handle = source;
    +
    + return 0;
    +}
    +
    +static __inline int time_pps_destroy(pps_handle_t handle)
    +{
    + return close(handle);
    +}
    +
    +static __inline int time_pps_getparams(pps_handle_t handle,
    + pps_params_t *ppsparams)
    +{
    + int ret;
    + struct pps_kparams __ppsparams;
    +
    + ret = ioctl(handle, PPS_GETPARAMS, &__ppsparams);
    +
    + ppsparams->api_version = __ppsparams.api_version;
    + ppsparams->mode = __ppsparams.mode;
    + ppsparams->assert_off_tu.tspec.tv_sec = __ppsparams.assert_off_tu.sec;
    + ppsparams->assert_off_tu.tspec.tv_nsec = __ppsparams.assert_off_tu.nsec;
    + ppsparams->clear_off_tu.tspec.tv_sec = __ppsparams.clear_off_tu.sec;
    + ppsparams->clear_off_tu.tspec.tv_nsec = __ppsparams.clear_off_tu.nsec;
    +
    + return ret;
    +}
    +
    +static __inline int time_pps_setparams(pps_handle_t handle,
    + const pps_params_t *ppsparams)
    +{
    + struct pps_kparams __ppsparams;
    +
    + __ppsparams.api_version = ppsparams->api_version;
    + __ppsparams.mode = ppsparams->mode;
    + __ppsparams.assert_off_tu.sec = ppsparams->assert_off_tu.tspec.tv_sec;
    + __ppsparams.assert_off_tu.nsec = ppsparams->assert_off_tu.tspec.tv_nsec;
    + __ppsparams.clear_off_tu.sec = ppsparams->clear_off_tu.tspec.tv_sec;
    + __ppsparams.clear_off_tu.nsec = ppsparams->clear_off_tu.tspec.tv_nsec;
    +
    + return ioctl(handle, PPS_SETPARAMS, &__ppsparams);
    +}
    +
    +/* Get capabilities for handle */
    +static __inline int time_pps_getcap(pps_handle_t handle, int *mode)
    +{
    + return ioctl(handle, PPS_GETCAP, mode);
    +}
    +
    +static __inline int time_pps_fetch(pps_handle_t handle, const int tsformat,
    + pps_info_t *ppsinfobuf,
    + const struct timespec *timeout)
    +{
    + struct pps_fdata __fdata;
    + int ret;
    +
    + /* Sanity checks */
    + if (tsformat != PPS_TSFMT_TSPEC) {
    + errno = EINVAL;
    + return -1;
    + }
    +
    + if (timeout) {
    + __fdata.timeout.sec = timeout->tv_sec;
    + __fdata.timeout.nsec = timeout->tv_nsec;
    + __fdata.timeout.flags = ~PPS_TIME_INVALID;
    + } else
    + __fdata.timeout.flags = PPS_TIME_INVALID;
    +
    + ret = ioctl(handle, PPS_FETCH, &__fdata);
    +
    + ppsinfobuf->assert_sequence = __fdata.info.assert_sequence;
    + ppsinfobuf->clear_sequence = __fdata.info.clear_sequence;
    + ppsinfobuf->assert_tu.tspec.tv_sec = __fdata.info.assert_tu.sec;
    + ppsinfobuf->assert_tu.tspec.tv_nsec = __fdata.info.assert_tu.nsec;
    + ppsinfobuf->clear_tu.tspec.tv_sec = __fdata.info.clear_tu.sec;
    + ppsinfobuf->clear_tu.tspec.tv_nsec = __fdata.info.clear_tu.nsec;
    + ppsinfobuf->current_mode = __fdata.info.current_mode;
    +
    + return ret;
    +}
    +
    +static __inline int time_pps_kcbind(pps_handle_t handle,
    + const int kernel_consumer,
    + const int edge, const int tsformat)
    +{
    + /* LinuxPPS doesn't implement kernel consumer feature */
    + errno = EOPNOTSUPP;
    + return -1;
    +}
    +
    +#endif /* _SYS_TIMEPPS_H_ */
    --
    1.5.2.5

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  4. [PATCH 1/7] LinuxPPS core support.

    This patch adds the kernel side of the PPS support currently named
    "LinuxPPS".

    PPS means "pulse per second" and a PPS source is just a device which
    provides a high precision signal each second so that an application
    can use it to adjust system clock time.

    Common use is the combination of the NTPD as userland program with a
    GPS receiver as PPS source to obtain a wallclock-time with
    sub-millisecond synchronisation to UTC.

    To obtain this goal the userland programs shoud use the PPS API
    specification (RFC 2783 - Pulse-Per-Second API for UNIX-like Operating
    Systems, Version 1.0) which in part is implemented by this patch. It
    provides a set of chars devices, one per PPS source, which can be used
    to get the time signal. The RFC's functions can be implemented by
    accessing to these char devices.

    Signed-off-by: Rodolfo Giometti
    ---
    Documentation/ABI/testing/sysfs-pps | 73 ++++++++
    Documentation/ioctl-number.txt | 2 +
    Documentation/pps/pps.txt | 170 +++++++++++++++++
    MAINTAINERS | 7 +
    drivers/Kconfig | 2 +
    drivers/Makefile | 1 +
    drivers/pps/Kconfig | 33 ++++
    drivers/pps/Makefile | 8 +
    drivers/pps/kapi.c | 272 ++++++++++++++++++++++++++++
    drivers/pps/pps.c | 342 +++++++++++++++++++++++++++++++++++
    drivers/pps/sysfs.c | 130 +++++++++++++
    include/linux/Kbuild | 1 +
    include/linux/pps.h | 204 +++++++++++++++++++++
    13 files changed, 1245 insertions(+), 0 deletions(-)
    create mode 100644 Documentation/ABI/testing/sysfs-pps
    create mode 100644 Documentation/pps/pps.txt
    create mode 100644 drivers/pps/Kconfig
    create mode 100644 drivers/pps/Makefile
    create mode 100644 drivers/pps/kapi.c
    create mode 100644 drivers/pps/pps.c
    create mode 100644 drivers/pps/sysfs.c
    create mode 100644 include/linux/pps.h

    diff --git a/Documentation/ABI/testing/sysfs-pps b/Documentation/ABI/testing/sysfs-pps
    new file mode 100644
    index 0000000..881b331
    --- /dev/null
    +++ b/Documentation/ABI/testing/sysfs-pps
    @@ -0,0 +1,73 @@
    +What: /sys/class/pps/
    +Date: February 2008
    +Contact: Rodolfo Giometti
    +Description:
    + The /sys/class/pps/ directory will contain files and
    + directories that will provide a unified interface to
    + the PPS sources.
    +
    +What: /sys/class/pps/ppsX/
    +Date: February 2008
    +Contact: Rodolfo Giometti
    +Description:
    + The /sys/class/pps/ppsX/ directory is related to X-th
    + PPS source into the system. Each directory will
    + contain files to manage and control its PPS source.
    +
    +What: /sys/class/pps/ppsX/assert
    +Date: February 2008
    +Contact: Rodolfo Giometti
    +Description:
    + The /sys/class/pps/ppsX/assert file reports the assert events
    + and the assert sequence number of the X-th source in the form:
    +
    + .#
    +
    + If the source has no assert events the content of this file
    + is void.
    +
    +What: /sys/class/pps/ppsX/clear
    +Date: February 2008
    +Contact: Rodolfo Giometti
    +Description:
    + The /sys/class/pps/ppsX/clear file reports the clear events
    + and the clear sequence number of the X-th source in the form:
    +
    + .#
    +
    + If the source has no clear events the content of this file
    + is void.
    +
    +What: /sys/class/pps/ppsX/mode
    +Date: February 2008
    +Contact: Rodolfo Giometti
    +Description:
    + The /sys/class/pps/ppsX/mode file reports the functioning
    + mode of the X-th source in hexadecimal encoding.
    +
    + Please, refer to linux/include/linux/pps.h for further
    + info.
    +
    +What: /sys/class/pps/ppsX/echo
    +Date: February 2008
    +Contact: Rodolfo Giometti
    +Description:
    + The /sys/class/pps/ppsX/echo file reports if the X-th source
    + supports or not an "echo" function.
    +
    +What: /sys/class/pps/ppsX/name
    +Date: February 2008
    +Contact: Rodolfo Giometti
    +Description:
    + The /sys/class/pps/ppsX/name file reports the name of the
    + X-th source.
    +
    +What: /sys/class/pps/ppsX/path
    +Date: February 2008
    +Contact: Rodolfo Giometti
    +Description:
    + The /sys/class/pps/ppsX/path file reports the path name of
    + the device connected with the X-th source.
    +
    + If the source is not connected with any device the content
    + of this file is void.
    diff --git a/Documentation/ioctl-number.txt b/Documentation/ioctl-number.txt
    index c18363b..b4c7d26 100644
    --- a/Documentation/ioctl-number.txt
    +++ b/Documentation/ioctl-number.txt
    @@ -97,6 +97,8 @@ Code Seq# Include File Comments
    'M' all linux/soundcard.h
    'N' 00-1F drivers/usb/scanner.h
    'P' all linux/soundcard.h
    +'P' 00-04 linux/pps.h LinuxPPS
    +
    'Q' all linux/soundcard.h
    'R' 00-1F linux/random.h
    'S' all linux/cdrom.h conflict!
    diff --git a/Documentation/pps/pps.txt b/Documentation/pps/pps.txt
    new file mode 100644
    index 0000000..c608aa8
    --- /dev/null
    +++ b/Documentation/pps/pps.txt
    @@ -0,0 +1,170 @@
    +
    + PPS - Pulse Per Second
    + ----------------------
    +
    +(C) Copyright 2007 Rodolfo Giometti
    +
    +This program is free software; you can redistribute it and/or modify
    +it under the terms of the GNU General Public License as published by
    +the Free Software Foundation; either version 2 of the License, or
    +(at your option) any later version.
    +
    +This program is distributed in the hope that it will be useful,
    +but WITHOUT ANY WARRANTY; without even the implied warranty of
    +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    +GNU General Public License for more details.
    +
    +
    +
    +Overview
    +--------
    +
    +LinuxPPS provides a programming interface (API) to define into the
    +system several PPS sources.
    +
    +PPS means "pulse per second" and a PPS source is just a device which
    +provides a high precision signal each second so that an application
    +can use it to adjust system clock time.
    +
    +A PPS source can be connected to a serial port (usually to the Data
    +Carrier Detect pin) or to a parallel port (ACK-pin) or to a special
    +CPU's GPIOs (this is the common case in embedded systems) but in each
    +case when a new pulse comes the system must apply to it a timestamp
    +and record it for the userland.
    +
    +Common use is the combination of the NTPD as userland program with a
    +GPS receiver as PPS source to obtain a wallclock-time with
    +sub-millisecond synchronisation to UTC.
    +
    +
    +RFC considerations
    +------------------
    +
    +While implementing a PPS API as RFC 2783 defines and using an embedded
    +CPU GPIO-Pin as physical link to the signal, I encountered a deeper
    +problem:
    +
    + At startup it needs a file descriptor as argument for the function
    + time_pps_create().
    +
    +This implies that the source has a /dev/... entry. This assumption is
    +ok for the serial and parallel port, where you can do something
    +useful besides(!) the gathering of timestamps as it is the central
    +task for a PPS-API. But this assumption does not work for a single
    +purpose GPIO line. In this case even basic file-related functionality
    +(like read() and write()) makes no sense at all and should not be a
    +precondition for the use of a PPS-API.
    +
    +The problem can be simply solved if you consider that a PPS source is
    +not always connected with a GPS data source.
    +
    +So your programs should check if the GPS data source (the serial port
    +for instance) is a PPS source too, otherwise they should provide the
    +possibility to open another device as PPS source.
    +
    +In LinuxPPS the PPS sources are simply char devices usually mapped
    +into files /dev/pps0, /dev/pps1, etc..
    +
    +
    +Coding example
    +--------------
    +
    +To register a PPS source into the kernel you should define a struct
    +pps_source_info_s as follow:
    +
    + static struct pps_source_info pps_ktimer_info = {
    + .name = "ktimer",
    + .path = "",
    + .mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT | \
    + PPS_ECHOASSERT | \
    + PPS_CANWAIT | PPS_TSFMT_TSPEC,
    + .echo = pps_ktimer_echo,
    + .owner = THIS_MODULE,
    + };
    +
    +and then calling the function pps_register_source() in your
    +intialization routine as follow:
    +
    + source = pps_register_source(&pps_ktimer_info,
    + PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
    +
    +The pps_register_source() prototype is:
    +
    + int pps_register_source(struct pps_source_info_s *info, int default_params)
    +
    +where "info" is a pointer to a structure that describes a particular
    +PPS source, "default_params" tells the system what the initial default
    +parameters for the device should be (is obvious that these parameters
    +must be a subset of ones defined into the struct
    +pps_source_info_s which describe the capabilities of the driver).
    +
    +Once you have registered a new PPS source into the system you can
    +signal an assert event (for example in the interrupt handler routine)
    +just using:
    +
    + pps_event(source, PPS_CAPTUREASSERT, ptr);
    +
    +The same function may also run the defined echo function
    +(pps_ktimer_echo(), passing to it the "ptr" pointer) if the user
    +asked for that... etc..
    +
    +Please see the file drivers/pps/clients/ktimer.c for example code.
    +
    +
    +SYSFS support
    +-------------
    +
    +If the SYSFS filesystem is enabled in the kernel it provides a new class:
    +
    + $ ls /sys/class/pps/
    + pps0/ pps1/ pps2/
    +
    +Every directory is the ID of a PPS sources defined into the system and
    +inside you find several files:
    +
    + $ ls /sys/class/pps/pps0/
    + assert clear echo mode name path subsystem@ uevent
    +
    +Inside each "assert" and "clear" file you can find the timestamp and a
    +sequence number:
    +
    + $ cat /sys/class/pps/pps0/assert
    + 1170026870.983207967#8
    +
    +Where before the "#" is the timestamp in seconds and after it is the
    +sequence number. Other files are:
    +
    +* echo: reports if the PPS source has an echo function or not;
    +
    +* mode: reports available PPS functioning modes;
    +
    +* name: reports the PPS source's name;
    +
    +* path: reports the PPS source's device path, that is the device the
    + PPS source is connected to (if it exists).
    +
    +
    +Testing the PPS support
    +-----------------------
    +
    +In order to test the PPS support even without specific hardware you can use
    +the ktimer driver (see the client subsection in the PPS configuration menu)
    +and the userland tools provided into Documentaion/pps/ directory.
    +
    +Once you have enabled the compilation of ktimer just modprobe it (if
    +not statically compiled):
    +
    + # modprobe ktimer
    +
    +and the run ppstest as follow:
    +
    + $ ./ppstest /dev/pps0
    + trying PPS source "/dev/pps1"
    + found PPS source "/dev/pps1"
    + ok, found 1 source(s), now start fetching data...
    + source 0 - assert 1186592699.388832443, sequence: 364 - clear 0.000000000, sequence: 0
    + source 0 - assert 1186592700.388931295, sequence: 365 - clear 0.000000000, sequence: 0
    + source 0 - assert 1186592701.389032765, sequence: 366 - clear 0.000000000, sequence: 0
    +
    +Please, note that to compile userland programs you need the file timepps.h
    +(see Documentation/pps/).
    diff --git a/MAINTAINERS b/MAINTAINERS
    index fed09b5..40d51c2 100644
    --- a/MAINTAINERS
    +++ b/MAINTAINERS
    @@ -3156,6 +3156,13 @@ P: James Chapman
    M: jchapman@katalix.com
    S: Maintained

    +PPS SUPPORT
    +P: Rodolfo Giometti
    +M: giometti@enneenne.com
    +W: http://wiki.enneenne.com/index.php/LinuxPPS_support
    +L: linuxpps@ml.enneenne.com
    +S: Maintained
    +
    PREEMPTIBLE KERNEL
    P: Robert Love
    M: rml@tech9.net
    diff --git a/drivers/Kconfig b/drivers/Kconfig
    index 3a0e354..0c11e5c 100644
    --- a/drivers/Kconfig
    +++ b/drivers/Kconfig
    @@ -52,6 +52,8 @@ source "drivers/i2c/Kconfig"

    source "drivers/spi/Kconfig"

    +source "drivers/pps/Kconfig"
    +
    source "drivers/gpio/Kconfig"

    source "drivers/w1/Kconfig"
    diff --git a/drivers/Makefile b/drivers/Makefile
    index e5e394a..adc0924 100644
    --- a/drivers/Makefile
    +++ b/drivers/Makefile
    @@ -62,6 +62,7 @@ obj-$(CONFIG_INPUT) += input/
    obj-$(CONFIG_I2O) += message/
    obj-$(CONFIG_RTC_LIB) += rtc/
    obj-y += i2c/
    +obj-$(CONFIG_PPS) += pps/
    obj-$(CONFIG_W1) += w1/
    obj-$(CONFIG_POWER_SUPPLY) += power/
    obj-$(CONFIG_HWMON) += hwmon/
    diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig
    new file mode 100644
    index 0000000..cc2eb8e
    --- /dev/null
    +++ b/drivers/pps/Kconfig
    @@ -0,0 +1,33 @@
    +#
    +# PPS support configuration
    +#
    +
    +menu "PPS support"
    +
    +config PPS
    + tristate "PPS support"
    + depends on EXPERIMENTAL
    + ---help---
    + PPS (Pulse Per Second) is a special pulse provided by some GPS
    + antennae. Userland can use it to get a high-precision time
    + reference.
    +
    + Some antennae's PPS signals are connected with the CD (Carrier
    + Detect) pin of the serial line they use to communicate with the
    + host. In this case use the SERIAL_LINE client support.
    +
    + Some antennae's PPS signals are connected with some special host
    + inputs so you have to enable the corresponding client support.
    +
    + To compile this driver as a module, choose M here: the module
    + will be called pps_core.ko.
    +
    +config PPS_DEBUG
    + bool "PPS debugging messages"
    + depends on PPS
    + help
    + Say Y here if you want the PPS support to produce a bunch of debug
    + messages to the system log. Select this if you are having a
    + problem with PPS support and want to see more of what is going on.
    +
    +endmenu
    diff --git a/drivers/pps/Makefile b/drivers/pps/Makefile
    new file mode 100644
    index 0000000..19ea582
    --- /dev/null
    +++ b/drivers/pps/Makefile
    @@ -0,0 +1,8 @@
    +#
    +# Makefile for the PPS core.
    +#
    +
    +pps_core-y := pps.o kapi.o sysfs.o
    +obj-$(CONFIG_PPS) := pps_core.o
    +
    +ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG
    diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
    new file mode 100644
    index 0000000..c127e66
    --- /dev/null
    +++ b/drivers/pps/kapi.c
    @@ -0,0 +1,272 @@
    +/*
    + * kapi.c -- kernel API
    + *
    + *
    + * Copyright (C) 2005-2007 Rodolfo Giometti
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    + */
    +
    +
    +#include
    +#include
    +#include
    +#include
    +#include
    +#include
    +#include
    +#include
    +#include
    +
    +/*
    + * Global variables
    + */
    +
    +DEFINE_SPINLOCK(idr_lock);
    +DEFINE_IDR(pps_idr);
    +
    +/*
    + * Local functions
    + */
    +
    +static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
    +{
    + ts->nsec += offset->nsec;
    + while (ts->nsec >= NSEC_PER_SEC) {
    + ts->nsec -= NSEC_PER_SEC;
    + ts->sec++;
    + }
    + while (ts->nsec < 0) {
    + ts->nsec += NSEC_PER_SEC;
    + ts->sec--;
    + }
    + ts->sec += offset->sec;
    +}
    +
    +/*
    + * Exported functions
    + */
    +
    +int pps_register_source(struct pps_source_info *info, int default_params)
    +{
    + struct pps_device *pps;
    + int id;
    + int err;
    +
    + /* Sanity checks */
    + if ((info->mode & default_params) != default_params) {
    + printk(KERN_ERR "pps: %s: unsupported default parameters\n",
    + info->name);
    + err = -EINVAL;
    + goto pps_register_source_exit;
    + }
    + if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 &&
    + info->echo == NULL) {
    + printk(KERN_ERR "pps: %s: echo function is not defined\n",
    + info->name);
    + err = -EINVAL;
    + goto pps_register_source_exit;
    + }
    + if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
    + printk(KERN_ERR "pps: %s: unspecified time format\n",
    + info->name);
    + err = -EINVAL;
    + goto pps_register_source_exit;
    + }
    +
    + /* Allocate memory for the new PPS source struct */
    + pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL);
    + if (pps == NULL) {
    + err = -ENOMEM;
    + goto pps_register_source_exit;
    + }
    +
    + /* Get new ID for the new PPS source */
    + if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
    + err = -ENOMEM;
    + goto kfree_pps;
    + }
    +
    + spin_lock_irq(&idr_lock);
    + err = idr_get_new(&pps_idr, pps, &id);
    + spin_unlock_irq(&idr_lock);
    +
    + if (err < 0)
    + goto kfree_pps;
    +
    + id = id & MAX_ID_MASK;
    + if (id >= PPS_MAX_SOURCES) {
    + printk(KERN_ERR "pps: %s: too many PPS sources in the system\n",
    + info->name);
    + err = -EBUSY;
    + goto free_idr;
    + }
    +
    + pps->id = id;
    + pps->params.api_version = PPS_API_VERS;
    + pps->params.mode = default_params;
    + pps->info = *info;
    +
    + init_waitqueue_head(&pps->queue);
    + spin_lock_init(&pps->lock);
    + atomic_set(&pps->usage, 0);
    + init_waitqueue_head(&pps->usage_queue);
    +
    + /* Create the char device */
    + err = pps_register_cdev(pps);
    + if (err < 0) {
    + printk(KERN_ERR "pps: %s: unable to create char device\n",
    + info->name);
    + goto free_idr;
    + }
    +
    + /* Create the sysfs entry */
    + err = pps_sysfs_create_source_entry(pps);
    + if (err < 0) {
    + printk(KERN_ERR "pps: %s: unable to create sysfs entries\n",
    + info->name);
    + goto unregister_cdev;
    + }
    +
    + pr_info("new PPS source %s at ID %d\n", info->name, id);
    +
    + return id;
    +
    +unregister_cdev:
    + pps_unregister_cdev(pps);
    +
    +free_idr:
    + spin_lock_irq(&idr_lock);
    + idr_remove(&pps_idr, id);
    + spin_unlock_irq(&idr_lock);
    +
    +kfree_pps:
    + kfree(pps);
    +
    +pps_register_source_exit:
    + printk(KERN_ERR "pps: %s: unable to register source\n", info->name);
    +
    + return err;
    +}
    +EXPORT_SYMBOL(pps_register_source);
    +
    +void pps_unregister_source(int source)
    +{
    + struct pps_device *pps;
    +
    + spin_lock_irq(&idr_lock);
    + pps = idr_find(&pps_idr, source);
    +
    + if (!pps) {
    + spin_unlock_irq(&idr_lock);
    + return;
    + }
    +
    + /* This should be done first in order to deny IRQ handlers
    + * to access PPS structs
    + */
    +
    + idr_remove(&pps_idr, pps->id);
    + spin_unlock_irq(&idr_lock);
    +
    + wait_event(pps->usage_queue, atomic_read(&pps->usage) == 0);
    +
    + pps_sysfs_remove_source_entry(pps);
    + pps_unregister_cdev(pps);
    + kfree(pps);
    +}
    +EXPORT_SYMBOL(pps_unregister_source);
    +
    +void pps_event(int source, int event, void *data)
    +{
    + struct pps_device *pps;
    + struct timespec __ts;
    + struct pps_ktime ts;
    + unsigned long flags;
    +
    + /* First of all we get the time stamp... */
    + getnstimeofday(&__ts);
    +
    + /* ... and translate it to PPS time data struct */
    + ts.sec = __ts.tv_sec;
    + ts.nsec = __ts.tv_nsec;
    +
    + if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
    + printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
    + event, source);
    + return;
    + }
    +
    + spin_lock_irqsave(&idr_lock, flags);
    + pps = idr_find(&pps_idr, source);
    +
    + /* If we find a valid PPS source we lock it before leaving
    + * the lock!
    + */
    + if (pps)
    + atomic_inc(&pps->usage);
    + spin_unlock_irqrestore(&idr_lock, flags);
    +
    + if (!pps)
    + return;
    +
    + pr_debug("PPS event on source %d at %llu.%06u\n",
    + pps->id, ts.sec, ts.nsec);
    +
    + spin_lock_irqsave(&pps->lock, flags);
    +
    + /* Must call the echo function? */
    + if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
    + pps->info.echo(source, event, data);
    +
    + /* Check the event */
    + pps->current_mode = pps->params.mode;
    + if (event & PPS_CAPTUREASSERT) {
    + /* We have to add an offset? */
    + if (pps->params.mode & PPS_OFFSETASSERT)
    + pps_add_offset(&ts, &pps->params.assert_off_tu);
    +
    + /* Save the time stamp */
    + pps->assert_tu = ts;
    + pps->assert_sequence++;
    + pr_debug("capture assert seq #%u for source %d\n",
    + pps->assert_sequence, source);
    + }
    + if (event & PPS_CAPTURECLEAR) {
    + /* We have to add an offset? */
    + if (pps->params.mode & PPS_OFFSETCLEAR)
    + pps_add_offset(&ts, &pps->params.clear_off_tu);
    +
    + /* Save the time stamp */
    + pps->clear_tu = ts;
    + pps->clear_sequence++;
    + pr_debug("capture clear seq #%u for source %d\n",
    + pps->clear_sequence, source);
    + }
    +
    + pps->go = ~0;
    + wake_up_interruptible(&pps->queue);
    +
    + kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
    +
    + spin_unlock_irqrestore(&pps->lock, flags);
    +
    + /* Now we can release the PPS source for (possible) deregistration */
    + spin_lock_irqsave(&idr_lock, flags);
    + atomic_dec(&pps->usage);
    + wake_up_all(&pps->usage_queue);
    + spin_unlock_irqrestore(&idr_lock, flags);
    +}
    +EXPORT_SYMBOL(pps_event);
    diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
    new file mode 100644
    index 0000000..53cce94
    --- /dev/null
    +++ b/drivers/pps/pps.c
    @@ -0,0 +1,342 @@
    +/*
    + * pps.c -- Main PPS support file
    + *
    + *
    + * Copyright (C) 2005-2007 Rodolfo Giometti
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    + */
    +
    +
    +#include
    +#include
    +#include
    +#include
    +#include
    +#include
    +#include
    +#include
    +#include
    +
    +/*
    + * Local variables
    + */
    +
    +static dev_t pps_devt;
    +static struct class *pps_class;
    +
    +/*
    + * Char device methods
    + */
    +
    +static unsigned int pps_cdev_poll(struct file *file, poll_table *wait)
    +{
    + struct pps_device *pps = file->private_data;
    +
    + poll_wait(file, &pps->queue, wait);
    +
    + return POLLIN | POLLRDNORM;
    +}
    +
    +static int pps_cdev_fasync(int fd, struct file *file, int on)
    +{
    + struct pps_device *pps = file->private_data;
    + return fasync_helper(fd, file, on, &pps->async_queue);
    +}
    +
    +static int pps_cdev_ioctl(struct inode *inode, struct file *file,
    + unsigned int cmd, unsigned long arg)
    +{
    + struct pps_device *pps = file->private_data;
    + struct pps_kparams params;
    + struct pps_fdata fdata;
    + unsigned long ticks;
    + void __user *uarg = (void __user *) arg;
    + int __user *iuarg = (int __user *) arg;
    + int err;
    +
    + switch (cmd) {
    + case PPS_CHECK:
    +
    + /* This does nothing but signal we are a PPS source... */
    +
    + return 0;
    +
    + case PPS_GETPARAMS:
    + pr_debug("PPS_GETPARAMS: source %d\n", pps->id);
    +
    + /* Sanity checks */
    + if (!uarg)
    + return -EINVAL;
    +
    + /* Return current parameters */
    + err = copy_to_user(uarg, &pps->params,
    + sizeof(struct pps_kparams));
    + if (err)
    + return -EFAULT;
    +
    + break;
    +
    + case PPS_SETPARAMS:
    + pr_debug("PPS_SETPARAMS: source %d\n", pps->id);
    +
    + /* Check the capabilities */
    + if (!capable(CAP_SYS_TIME))
    + return -EPERM;
    +
    + /* Sanity checks */
    + if (!uarg)
    + return -EINVAL;
    + err = copy_from_user(&params, uarg, sizeof(struct pps_kparams));
    + if (err)
    + return -EFAULT;
    + if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {
    + pr_debug("capture mode unspecified (%x)\n",
    + params.mode);
    + return -EINVAL;
    + }
    +
    + /* Check for supported capabilities */
    + if ((params.mode & ~pps->info.mode) != 0) {
    + pr_debug("unsupported capabilities (%x)\n",
    + params.mode);
    + return -EINVAL;
    + }
    +
    + spin_lock_irq(&pps->lock);
    +
    + /* Save the new parameters */
    + pps->params = params;
    +
    + /* Restore the read only parameters */
    + if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
    + /* section 3.3 of RFC 2783 interpreted */
    + pr_debug("time format unspecified (%x)\n",
    + params.mode);
    + pps->params.mode |= PPS_TSFMT_TSPEC;
    + }
    + if (pps->info.mode & PPS_CANWAIT)
    + pps->params.mode |= PPS_CANWAIT;
    + pps->params.api_version = PPS_API_VERS;
    +
    + spin_unlock_irq(&pps->lock);
    +
    + break;
    +
    + case PPS_GETCAP:
    + pr_debug("PPS_GETCAP: source %d\n", pps->id);
    +
    + /* Sanity checks */
    + if (!uarg)
    + return -EINVAL;
    +
    + err = put_user(pps->info.mode, iuarg);
    + if (err)
    + return -EFAULT;
    +
    + break;
    +
    + case PPS_FETCH:
    + pr_debug("PPS_FETCH: source %d\n", pps->id);
    +
    + if (!uarg)
    + return -EINVAL;
    + err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
    + if (err)
    + return -EFAULT;
    +
    + pps->go = 0;
    +
    + /* Manage the timeout */
    + if (fdata.timeout.flags & PPS_TIME_INVALID)
    + err = wait_event_interruptible(pps->queue, pps->go);
    + else {
    + pr_debug("timeout %lld.%09d\n",
    + fdata.timeout.sec, fdata.timeout.nsec);
    + ticks = fdata.timeout.sec * HZ;
    + ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);
    +
    + if (ticks != 0) {
    + err = wait_event_interruptible_timeout(
    + pps->queue, pps->go, ticks);
    + if (err == 0)
    + return -ETIMEDOUT;
    + }
    + }
    +
    + /* Check for pending signals */
    + if (err == -ERESTARTSYS) {
    + pr_debug("pending signal caught\n");
    + return -EINTR;
    + }
    +
    + /* Return the fetched timestamp */
    + spin_lock_irq(&pps->lock);
    +
    + fdata.info.assert_sequence = pps->assert_sequence;
    + fdata.info.clear_sequence = pps->clear_sequence;
    + fdata.info.assert_tu = pps->assert_tu;
    + fdata.info.clear_tu = pps->clear_tu;
    + fdata.info.current_mode = pps->current_mode;
    +
    + spin_unlock_irq(&pps->lock);
    +
    + err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
    + if (err)
    + return -EFAULT;
    +
    + break;
    +
    + default:
    + return -ENOTTY;
    + break;
    + }
    +
    + return 0;
    +}
    +
    +static int pps_cdev_open(struct inode *inode, struct file *file)
    +{
    + struct pps_device *pps = container_of(inode->i_cdev,
    + struct pps_device, cdev);
    + int found;
    +
    + spin_lock_irq(&idr_lock);
    + found = idr_find(&pps_idr, pps->id) != NULL;
    +
    + /* Lock the PPS source against (possible) deregistration */
    + if (found)
    + atomic_inc(&pps->usage);
    +
    + spin_unlock_irq(&idr_lock);
    +
    + if (!found)
    + return -ENODEV;
    +
    + file->private_data = pps;
    +
    + return 0;
    +}
    +
    +static int pps_cdev_release(struct inode *inode, struct file *file)
    +{
    + struct pps_device *pps = file->private_data;
    +
    + /* Free the PPS source and wake up (possible) deregistration */
    + atomic_dec(&pps->usage);
    + wake_up_all(&pps->usage_queue);
    +
    + return 0;
    +}
    +
    +/*
    + * Char device stuff
    + */
    +
    +static const struct file_operations pps_cdev_fops = {
    + .owner = THIS_MODULE,
    + .llseek = no_llseek,
    + .poll = pps_cdev_poll,
    + .fasync = pps_cdev_fasync,
    + .ioctl = pps_cdev_ioctl,
    + .open = pps_cdev_open,
    + .release = pps_cdev_release,
    +};
    +
    +int pps_register_cdev(struct pps_device *pps)
    +{
    + int err;
    +
    + pps->devno = MKDEV(MAJOR(pps_devt), pps->id);
    + cdev_init(&pps->cdev, &pps_cdev_fops);
    + pps->cdev.owner = pps->info.owner;
    +
    + err = cdev_add(&pps->cdev, pps->devno, 1);
    + if (err) {
    + printk(KERN_ERR "pps: %s: failed to add char device %d:%d\n",
    + pps->info.name, MAJOR(pps_devt), pps->id);
    + return err;
    + }
    + pps->dev = device_create(pps_class, pps->info.dev, pps->devno,
    + "pps%d", pps->id);
    + if (err)
    + goto del_cdev;
    + dev_set_drvdata(pps->dev, pps);
    +
    + pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
    + MAJOR(pps_devt), pps->id);
    +
    + return 0;
    +
    +del_cdev:
    + cdev_del(&pps->cdev);
    +
    + return err;
    +}
    +
    +void pps_unregister_cdev(struct pps_device *pps)
    +{
    + device_destroy(pps_class, pps->devno);
    + cdev_del(&pps->cdev);
    +}
    +
    +/*
    + * Module stuff
    + */
    +
    +static void __exit pps_exit(void)
    +{
    + class_destroy(pps_class);
    +
    + if (pps_devt)
    + unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
    +
    + pr_info("LinuxPPS API ver. %d removed\n", PPS_API_VERS);
    +}
    +
    +static int __init pps_init(void)
    +{
    + int err;
    +
    + pps_class = class_create(THIS_MODULE, "pps");
    + if (!pps_class) {
    + printk(KERN_ERR "pps: failed to allocate class\n");
    + return -ENOMEM;
    + }
    +
    + err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
    + if (err < 0) {
    + printk(KERN_ERR "pps: failed to allocate char device region\n");
    + goto remove_class;
    + }
    +
    + pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
    + pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
    + "\n", PPS_VERSION);
    +
    + return 0;
    +
    +remove_class:
    + class_destroy(pps_class);
    +
    + return err;
    +}
    +
    +subsys_initcall(pps_init);
    +module_exit(pps_exit);
    +
    +MODULE_AUTHOR("Rodolfo Giometti ");
    +MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
    +MODULE_LICENSE("GPL");
    diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c
    new file mode 100644
    index 0000000..c25c91c
    --- /dev/null
    +++ b/drivers/pps/sysfs.c
    @@ -0,0 +1,130 @@
    +/*
    + * sysfs.c -- sysfs support
    + *
    + *
    + * Copyright (C) 2007 Rodolfo Giometti
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    + */
    +
    +
    +#include
    +#include
    +#include
    +#include
    +
    +/*
    + * Attribute functions
    + */
    +
    +static ssize_t pps_show_assert(struct device *dev,
    + struct device_attribute *attr, char *buf)
    +{
    + struct pps_device *pps = dev_get_drvdata(dev);
    +
    + if (!(pps->info.mode & PPS_CAPTUREASSERT))
    + return 0;
    +
    + return sprintf(buf, "%lld.%09d#%d\n",
    + pps->assert_tu.sec, pps->assert_tu.nsec,
    + pps->assert_sequence);
    +}
    +DEVICE_ATTR(assert, S_IRUGO, pps_show_assert, NULL);
    +
    +static ssize_t pps_show_clear(struct device *dev,
    + struct device_attribute *attr, char *buf)
    +{
    + struct pps_device *pps = dev_get_drvdata(dev);
    +
    + if (!(pps->info.mode & PPS_CAPTURECLEAR))
    + return 0;
    +
    + return sprintf(buf, "%lld.%09d#%d\n",
    + pps->clear_tu.sec, pps->clear_tu.nsec,
    + pps->clear_sequence);
    +}
    +DEVICE_ATTR(clear, S_IRUGO, pps_show_clear, NULL);
    +
    +static ssize_t pps_show_mode(struct device *dev,
    + struct device_attribute *attr, char *buf)
    +{
    + struct pps_device *pps = dev_get_drvdata(dev);
    +
    + return sprintf(buf, "%4x\n", pps->info.mode);
    +}
    +DEVICE_ATTR(mode, S_IRUGO, pps_show_mode, NULL);
    +
    +static ssize_t pps_show_echo(struct device *dev,
    + struct device_attribute *attr, char *buf)
    +{
    + struct pps_device *pps = dev_get_drvdata(dev);
    +
    + return sprintf(buf, "%d\n", !!pps->info.echo);
    +}
    +DEVICE_ATTR(echo, S_IRUGO, pps_show_echo, NULL);
    +
    +static ssize_t pps_show_name(struct device *dev,
    + struct device_attribute *attr, char *buf)
    +{
    + struct pps_device *pps = dev_get_drvdata(dev);
    +
    + return sprintf(buf, "%s\n", pps->info.name);
    +}
    +DEVICE_ATTR(name, S_IRUGO, pps_show_name, NULL);
    +
    +static ssize_t pps_show_path(struct device *dev,
    + struct device_attribute *attr, char *buf)
    +{
    + struct pps_device *pps = dev_get_drvdata(dev);
    +
    + return sprintf(buf, "%s\n", pps->info.path);
    +}
    +DEVICE_ATTR(path, S_IRUGO, pps_show_path, NULL);
    +
    +static struct attribute *pps_attrs[] = {
    + &dev_attr_mode.attr,
    + &dev_attr_echo.attr,
    + &dev_attr_name.attr,
    + &dev_attr_path.attr,
    + &dev_attr_assert.attr,
    + &dev_attr_clear.attr,
    + NULL
    +};
    +
    +static struct attribute_group pps_group = {
    + .attrs = pps_attrs,
    +};
    +
    +/*
    + * Public functions
    + */
    +
    +void pps_sysfs_remove_source_entry(struct pps_device *pps)
    +{
    + /* Delete info files */
    + sysfs_remove_group(&pps->dev->kobj, &pps_group);
    +}
    +
    +int pps_sysfs_create_source_entry(struct pps_device *pps)
    +{
    + int ret;
    +
    + /* Create info files */
    + ret = sysfs_create_group(&pps->dev->kobj, &pps_group);
    + if (ret)
    + dev_err(pps->dev, "unable to create default sysfs entries");
    +
    + return 0;
    +}
    diff --git a/include/linux/Kbuild b/include/linux/Kbuild
    index aada32f..c4cbd8d 100644
    --- a/include/linux/Kbuild
    +++ b/include/linux/Kbuild
    @@ -297,6 +297,7 @@ unifdef-y += pmu.h
    unifdef-y += poll.h
    unifdef-y += ppp_defs.h
    unifdef-y += ppp-comp.h
    +unifdef-y += pps.h
    unifdef-y += ptrace.h
    unifdef-y += qnx4_fs.h
    unifdef-y += quota.h
    diff --git a/include/linux/pps.h b/include/linux/pps.h
    new file mode 100644
    index 0000000..c455443
    --- /dev/null
    +++ b/include/linux/pps.h
    @@ -0,0 +1,204 @@
    +/*
    + * pps.h -- PPS API kernel header.
    + *
    + *
    + * Copyright (C) 2005-2007 Rodolfo Giometti
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    + */
    +
    +
    +#ifndef _PPS_H_
    +#define _PPS_H_
    +
    +/* Implementation note: the logical states ``assert'' and ``clear''
    + * are implemented in terms of the chip register, i.e. ``assert''
    + * means the bit is set. */
    +
    +/*
    + * 3.2 New data structures
    + */
    +
    +#ifndef __KERNEL__
    +#include
    +#include
    +#include
    +#else
    +#include
    +#endif
    +
    +#define PPS_API_VERS_1 1
    +#define PPS_API_VERS PPS_API_VERS_1 /* we use API version 1 */
    +#define PPS_MAX_NAME_LEN 32
    +
    +/* 32-bit vs. 64-bit compatibility.
    + *
    + * 0n i386, the alignment of a uint64_t is only 4 bytes, while on most other
    + * architectures it's 8 bytes. On i386, there will be no padding between the
    + * two consecutive 'struct pps_ktime' members of struct pps_kinfo and struct
    + * pps_kparams. But on most platforms there will be padding to ensure correct
    + * alignment.
    + *
    + * The simple fix is probably to add an explicit padding.
    + * [David Woodhouse]
    + */
    +struct pps_ktime {
    + __s64 sec;
    + __s32 nsec;
    + __u32 flags;
    +};
    +#define PPS_TIME_INVALID (1<<0) /* used to specify timeout==NULL */
    +
    +struct pps_kinfo {
    + __u32 assert_sequence; /* seq. num. of assert event */
    + __u32 clear_sequence; /* seq. num. of clear event */
    + struct pps_ktime assert_tu; /* time of assert event */
    + struct pps_ktime clear_tu; /* time of clear event */
    + int current_mode; /* current mode bits */
    +};
    +
    +struct pps_kparams {
    + int api_version; /* API version # */
    + int mode; /* mode bits */
    + struct pps_ktime assert_off_tu; /* offset compensation for assert */
    + struct pps_ktime clear_off_tu; /* offset compensation for clear */
    +};
    +
    +/*
    + * 3.3 Mode bit definitions
    + */
    +
    +/* Device/implementation parameters */
    +#define PPS_CAPTUREASSERT 0x01 /* capture assert events */
    +#define PPS_CAPTURECLEAR 0x02 /* capture clear events */
    +#define PPS_CAPTUREBOTH 0x03 /* capture assert and clear events */
    +
    +#define PPS_OFFSETASSERT 0x10 /* apply compensation for assert ev. */
    +#define PPS_OFFSETCLEAR 0x20 /* apply compensation for clear ev. */
    +
    +#define PPS_CANWAIT 0x100 /* can we wait for an event? */
    +#define PPS_CANPOLL 0x200 /* bit reserved for future use */
    +
    +/* Kernel actions */
    +#define PPS_ECHOASSERT 0x40 /* feed back assert event to output */
    +#define PPS_ECHOCLEAR 0x80 /* feed back clear event to output */
    +
    +/* Timestamp formats */
    +#define PPS_TSFMT_TSPEC 0x1000 /* select timespec format */
    +#define PPS_TSFMT_NTPFP 0x2000 /* select NTP format */
    +
    +/*
    + * 3.4.4 New functions: disciplining the kernel timebase
    + */
    +
    +/* Kernel consumers */
    +#define PPS_KC_HARDPPS 0 /* hardpps() (or equivalent) */
    +#define PPS_KC_HARDPPS_PLL 1 /* hardpps() constrained to
    + use a phase-locked loop */
    +#define PPS_KC_HARDPPS_FLL 2 /* hardpps() constrained to
    + use a frequency-locked loop */
    +/*
    + * Here begins the implementation-specific part!
    + */
    +
    +struct pps_fdata {
    + struct pps_kinfo info;
    + struct pps_ktime timeout;
    +};
    +
    +#include
    +
    +#define PPS_CHECK _IO('P', 0)
    +#define PPS_GETPARAMS _IOR('P', 1, struct pps_kparams *)
    +#define PPS_SETPARAMS _IOW('P', 2, struct pps_kparams *)
    +#define PPS_GETCAP _IOR('P', 3, int *)
    +#define PPS_FETCH _IOWR('P', 4, struct pps_fdata *)
    +
    +#ifdef __KERNEL__
    +
    +#include
    +#include
    +
    +#define PPS_VERSION "5.0.0"
    +#define PPS_MAX_SOURCES 16 /* should be enough... */
    +
    +/*
    + * Global defines
    + */
    +
    +/* The specific PPS source info */
    +struct pps_source_info {
    + char name[PPS_MAX_NAME_LEN]; /* simbolic name */
    + char path[PPS_MAX_NAME_LEN]; /* path of connected device */
    + int mode; /* PPS's allowed mode */
    +
    + void (*echo)(int source, int event, void *data); /* PPS echo function */
    +
    + struct module *owner;
    + struct device *dev;
    +};
    +
    +/* The main struct */
    +struct pps_device {
    + struct pps_source_info info; /* PSS source info */
    +
    + struct pps_kparams params; /* PPS's current params */
    +
    + __u32 assert_sequence; /* PPS' assert event seq # */
    + __u32 clear_sequence; /* PPS' clear event seq # */
    + struct pps_ktime assert_tu;
    + struct pps_ktime clear_tu;
    + int current_mode; /* PPS mode at event time */
    +
    + int go; /* PPS event is arrived? */
    + wait_queue_head_t queue; /* PPS event queue */
    +
    + unsigned int id; /* PPS source unique ID */
    + struct cdev cdev;
    + struct device *dev;
    + int devno;
    + struct fasync_struct *async_queue; /* fasync method */
    + spinlock_t lock;
    +
    + atomic_t usage; /* usage count */
    + wait_queue_head_t usage_queue;
    +
    + struct class class_dev;
    +};
    +
    +/*
    + * Global variables
    + */
    +
    +extern spinlock_t idr_lock;
    +extern struct idr pps_idr;
    +
    +/*
    + * Exported functions
    + */
    +
    +extern int pps_register_source(struct pps_source_info *info,
    + int default_params);
    +extern void pps_unregister_source(int source);
    +extern int pps_register_cdev(struct pps_device *pps);
    +extern void pps_unregister_cdev(struct pps_device *pps);
    +extern void pps_event(int source, int event, void *data);
    +
    +extern int pps_sysfs_create_source_entry(struct pps_device *pps);
    +extern void pps_sysfs_remove_source_entry(struct pps_device *pps);
    +
    +#endif /* __KERNEL__ */
    +
    +#endif /* _PPS_H_ */
    --
    1.5.2.5

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  5. Re: LinuxPPS (RESUBMIT 2): the PPS Linux implementation.

    On Thu, Mar 6, 2008 at 5:08 AM, Rodolfo Giometti wrote:
    > This patch set adds the PPS support into Linux.
    >
    > PPS means "pulse per second" and its API is specified by RFC 2783
    > (Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0).
    >
    > The code has been tested with the NTPD program
    > (http://www.eecis.udel.edu/~mills/ntp/html/index.html) and several GPS
    > antennae.


    Hey Andrew,
    Are there any remaining objections that are keeping you from picking
    this patchset up?

    thanks
    -john
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  6. Re: LinuxPPS (RESUBMIT 2): the PPS Linux implementation.

    On Wed, 19 Mar 2008 10:29:34 -0700
    "john stultz" wrote:

    > On Thu, Mar 6, 2008 at 5:08 AM, Rodolfo Giometti wrote:
    > > This patch set adds the PPS support into Linux.
    > >
    > > PPS means "pulse per second" and its API is specified by RFC 2783
    > > (Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0).
    > >
    > > The code has been tested with the NTPD program
    > > (http://www.eecis.udel.edu/~mills/ntp/html/index.html) and several GPS
    > > antennae.

    >
    > Hey Andrew,
    > Are there any remaining objections that are keeping you from picking
    > this patchset up?


    Not as far as I know. They're in my queue-to-review. Assistance there is
    always useful

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  7. Re: LinuxPPS (RESUBMIT 2): the PPS Linux implementation.

    On Wed, Mar 19, 2008 at 02:21:13PM -0700, Andrew Morton wrote:
    > On Wed, 19 Mar 2008 10:29:34 -0700
    > "john stultz" wrote:
    >
    > > On Thu, Mar 6, 2008 at 5:08 AM, Rodolfo Giometti wrote:
    > > > This patch set adds the PPS support into Linux.
    > > >
    > > > PPS means "pulse per second" and its API is specified by RFC 2783
    > > > (Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0).
    > > >
    > > > The code has been tested with the NTPD program
    > > > (http://www.eecis.udel.edu/~mills/ntp/html/index.html) and several GPS
    > > > antennae.

    > >
    > > Hey Andrew,
    > > Are there any remaining objections that are keeping you from picking
    > > this patchset up?

    >
    > Not as far as I know. They're in my queue-to-review. Assistance there is
    > always useful


    I looked it over a few times now, and didn't find anything objectionable.
    But then, your standards are always somewhat higher than mine

    Dave

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  8. Re: [PATCH 5/7] PPS: serial clients support.

    On Thu, 6 Mar 2008 13:09:04 +0100
    Rodolfo Giometti wrote:

    > Adds support for the PPS sources connected with the CD (Carrier
    > Detect) pin of a serial port.
    >
    > ...
    >
    > +#ifdef CONFIG_PPS_CLIENT_UART
    > +
    > +static int
    > +uart_register_pps_port(struct uart_state *state, struct uart_port *port)
    > +{
    > + struct tty_driver *drv = port->info->tty->driver;
    > + int ret;
    > +
    > + state->pps_info.owner = THIS_MODULE;
    > + state->pps_info.dev = port->dev;
    > + snprintf(state->pps_info.name, PPS_MAX_NAME_LEN, "%s%d",
    > + drv->driver_name, port->line);
    > + snprintf(state->pps_info.path, PPS_MAX_NAME_LEN, "/dev/%s%d",
    > + drv->name, port->line);


    umm, why are we hard-wiring "/dev" into the kernel source? Is it just for
    user-friendly printks?

    > + state->pps_info.mode = PPS_CAPTUREBOTH | \
    > + PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
    > + PPS_CANWAIT | PPS_TSFMT_TSPEC;
    > +
    > + ret = pps_register_source(&state->pps_info, PPS_CAPTUREBOTH | \
    > + PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
    > + if (ret < 0) {
    > + dev_err(port->dev, "cannot register PPS source \"%s\"\n",
    > + state->pps_info.path);
    > + return ret;
    > + }
    > + port->pps_source = ret;
    > + dev_dbg(port->dev, "PPS source #%d \"%s\" added\n",
    > + port->pps_source, state->pps_info.path);
    > +
    > + return 0;
    > +}
    > +
    > +static void
    > +uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
    > +{
    > + pps_unregister_source(port->pps_source);
    > + dev_dbg(port->dev, "PPS source #%d \"%s\" removed\n",
    > + port->pps_source, state->pps_info.path);
    > +}
    > +
    > +#else
    > +
    > +#define uart_register_pps_port(state, port) do { } while (0)
    > +#define uart_unregister_pps_port(state, port) do { } while (0)


    Please never implement in cpp that which can be implemented in C. These
    should have been static inlines. That's nicer, matches the
    CONFIG_PPS_CLIENT_UART=y code and provides type checking.

    > +#endif /* CONFIG_PPS_CLIENT_UART */
    > +
    > static int uart_set_info(struct uart_state *state,
    > struct serial_struct __user *newinfo)
    > {
    > @@ -810,11 +859,19 @@ static int uart_set_info(struct uart_state *state,
    > (port->flags & UPF_LOW_LATENCY) ? 1 : 0;
    >
    > check_and_exit:
    > + /* PPS support enabled/disabled? */
    > + if ((old_flags & UPF_HARDPPS_CD) != (new_flags & UPF_HARDPPS_CD)) {
    > + if (new_flags & UPF_HARDPPS_CD)
    > + uart_register_pps_port(state, port);
    > + else
    > + uart_unregister_pps_port(state, port);
    > + }
    > +
    > retval = 0;
    > if (port->type == PORT_UNKNOWN)
    > goto exit;
    > if (state->info->flags & UIF_INITIALIZED) {
    > - if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||
    > + if (((old_flags ^ port->flags) & (UPF_SPD_MASK|UPF_HARDPPS_CD)) ||
    > old_custom_divisor != port->custom_divisor) {
    > /*
    > * If they're setting up a custom divisor or speed,
    > @@ -2148,6 +2205,12 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
    > port->ops->config_port(port, flags);
    > }
    >
    > + /*
    > + * Add the PPS support for the current port.
    > + */
    > + if (port->flags & UPF_HARDPPS_CD)
    > + uart_register_pps_port(state, port);
    > +
    > if (port->type != PORT_UNKNOWN) {
    > unsigned long flags;
    >
    > @@ -2405,6 +2468,12 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
    > mutex_unlock(&state->mutex);
    >
    > /*
    > + * Remove PPS support from the current port.
    > + */
    > + if (port->flags & UPF_HARDPPS_CD)
    > + uart_unregister_pps_port(state, port);
    > +
    > + /*
    > * Remove the devices from the tty layer
    > */
    > tty_unregister_device(drv->tty_driver, port->line);


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  9. Re: [PATCH 1/7] LinuxPPS core support.

    On Thu, 6 Mar 2008 13:09:00 +0100
    Rodolfo Giometti wrote:

    > +pps_core-y := pps.o kapi.o sysfs.o


    Does it compile OK with CONFIG_SYSFS=n?

    > +#include
    > +#include
    > +#include
    > +#include
    > +#include
    > +#include
    > +#include
    > +#include
    > +#include
    > +
    > +/*
    > + * Global variables
    > + */
    > +
    > +DEFINE_SPINLOCK(idr_lock);


    This name is insufficiently specific. Not only does it risk linkage
    errors, it makes it ahrd for poeple to work out where the symbol came from.

    I renamed it to pps_idr_lock.

    > +DEFINE_IDR(pps_idr);
    >
    > ...
    >
    > +void pps_unregister_source(int source)
    > +{
    > + struct pps_device *pps;
    > +
    > + spin_lock_irq(&idr_lock);
    > + pps = idr_find(&pps_idr, source);
    > +
    > + if (!pps) {
    > + spin_unlock_irq(&idr_lock);
    > + return;
    > + }
    > +
    > + /* This should be done first in order to deny IRQ handlers
    > + * to access PPS structs
    > + */
    > +
    > + idr_remove(&pps_idr, pps->id);
    > + spin_unlock_irq(&idr_lock);
    > +
    > + wait_event(pps->usage_queue, atomic_read(&pps->usage) == 0);
    > +
    > + pps_sysfs_remove_source_entry(pps);
    > + pps_unregister_cdev(pps);
    > + kfree(pps);
    > +}
    > +EXPORT_SYMBOL(pps_unregister_source);


    The wait_event() stuff really shouldn't be here: it should be integral to
    the refcounting:

    void pps_dev_put(struct pps_device *pps)
    {
    spin_lock_irq(&pps_lock);
    if (atomic_dec_and_test(&pps->usage))
    idr_remove(&pps_idr, pps->id);
    else
    pps = NULL;
    spin_unlock_irq(&pps_lock);
    if (pps) {
    /*
    * Might need to do the below via schedule_work() if
    * pps_dev_put() is to be callable from atomic context
    */
    pps_sysfs_remove_source_entry(pps);
    pps_unregister_cdev(pps);
    kfree(pps);
    }
    }

    As it stands, there might be deadlocks such as when a process which itself
    holds a ref on the pps_device (with an open fd?) calls
    pps_unregister_source.

    Also, we need to take care that all processes which were waiting in
    pps_unregister_source() get to finish their cleanup before we permit rmmod
    to proceed. Is that handled somewhere?

    > +void pps_event(int source, int event, void *data)


    Please document the API in the kernel source. I realise there's a teeny
    bit of documentation in pps.txt, but people don't think to look there and
    it tends to go out of date.

    It doesn't have to be fancy formal kerneldoc - it's better to add *good*
    comments which tell people what they need to know. For some reason people
    seem to add useless obvious stuff when they do their comments in kerneldoc
    form.

    > +{
    > + struct pps_device *pps;
    > + struct timespec __ts;
    > + struct pps_ktime ts;
    > + unsigned long flags;
    > +
    > + /* First of all we get the time stamp... */
    > + getnstimeofday(&__ts);
    > +
    > + /* ... and translate it to PPS time data struct */
    > + ts.sec = __ts.tv_sec;
    > + ts.nsec = __ts.tv_nsec;
    > +
    > + if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
    > + printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
    > + event, source);
    > + return;
    > + }
    > +
    > + spin_lock_irqsave(&idr_lock, flags);
    > + pps = idr_find(&pps_idr, source);
    > +
    > + /* If we find a valid PPS source we lock it before leaving
    > + * the lock!
    > + */
    > + if (pps)
    > + atomic_inc(&pps->usage);
    > + spin_unlock_irqrestore(&idr_lock, flags);


    The above pattern is repeated rather a lot and could perhaps be extracted
    into a nice pps_dev_get() helper.

    > + if (!pps)
    > + return;
    > +
    > + pr_debug("PPS event on source %d at %llu.%06u\n",
    > + pps->id, ts.sec, ts.nsec);
    > +
    > + spin_lock_irqsave(&pps->lock, flags);
    > +
    > + /* Must call the echo function? */
    > + if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
    > + pps->info.echo(source, event, data);
    > +
    > + /* Check the event */
    > + pps->current_mode = pps->params.mode;
    > + if (event & PPS_CAPTUREASSERT) {
    > + /* We have to add an offset? */
    > + if (pps->params.mode & PPS_OFFSETASSERT)
    > + pps_add_offset(&ts, &pps->params.assert_off_tu);
    > +
    > + /* Save the time stamp */
    > + pps->assert_tu = ts;
    > + pps->assert_sequence++;
    > + pr_debug("capture assert seq #%u for source %d\n",
    > + pps->assert_sequence, source);
    > + }
    > + if (event & PPS_CAPTURECLEAR) {
    > + /* We have to add an offset? */
    > + if (pps->params.mode & PPS_OFFSETCLEAR)
    > + pps_add_offset(&ts, &pps->params.clear_off_tu);
    > +
    > + /* Save the time stamp */
    > + pps->clear_tu = ts;
    > + pps->clear_sequence++;
    > + pr_debug("capture clear seq #%u for source %d\n",
    > + pps->clear_sequence, source);
    > + }
    > +
    > + pps->go = ~0;
    > + wake_up_interruptible(&pps->queue);
    > +
    > + kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
    > +
    > + spin_unlock_irqrestore(&pps->lock, flags);
    > +
    > + /* Now we can release the PPS source for (possible) deregistration */
    > + spin_lock_irqsave(&idr_lock, flags);
    > + atomic_dec(&pps->usage);
    > + wake_up_all(&pps->usage_queue);
    > + spin_unlock_irqrestore(&idr_lock, flags);
    > +}
    > +EXPORT_SYMBOL(pps_event);
    >
    > ...
    >
    > +static int pps_cdev_open(struct inode *inode, struct file *file)
    > +{
    > + struct pps_device *pps = container_of(inode->i_cdev,
    > + struct pps_device, cdev);
    > + int found;
    > +
    > + spin_lock_irq(&idr_lock);
    > + found = idr_find(&pps_idr, pps->id) != NULL;
    > +
    > + /* Lock the PPS source against (possible) deregistration */
    > + if (found)
    > + atomic_inc(&pps->usage);
    > +
    > + spin_unlock_irq(&idr_lock);


    That looks a bit odd. How can the pps_device not be registered in the IDR
    tree at this stage?


    > + if (!found)
    > + return -ENODEV;
    > +
    > + file->private_data = pps;
    > +
    > + return 0;
    > +}
    >
    > ...
    >
    > +/* Kernel consumers */
    > +#define PPS_KC_HARDPPS 0 /* hardpps() (or equivalent) */
    > +#define PPS_KC_HARDPPS_PLL 1 /* hardpps() constrained to
    > + use a phase-locked loop */
    > +#define PPS_KC_HARDPPS_FLL 2 /* hardpps() constrained to
    > + use a frequency-locked loop */
    > +/*
    > + * Here begins the implementation-specific part!
    > + */
    > +
    > +struct pps_fdata {
    > + struct pps_kinfo info;
    > + struct pps_ktime timeout;
    > +};
    > +
    > +#include
    > +
    > +#define PPS_CHECK _IO('P', 0)
    > +#define PPS_GETPARAMS _IOR('P', 1, struct pps_kparams *)
    > +#define PPS_SETPARAMS _IOW('P', 2, struct pps_kparams *)
    > +#define PPS_GETCAP _IOR('P', 3, int *)
    > +#define PPS_FETCH _IOWR('P', 4, struct pps_fdata *)
    > +
    > +#ifdef __KERNEL__
    > +
    > +#include
    > +#include
    > +
    > +#define PPS_VERSION "5.0.0"
    > +#define PPS_MAX_SOURCES 16 /* should be enough... */


    It's nice to avoid sprinkling #includes throughout the file, please.
    People expect to be able to see what's being included in the first
    screenful of the file.

    > +/*
    > + * Global defines
    > + */
    > +
    > +/* The specific PPS source info */
    > +struct pps_source_info {
    > + char name[PPS_MAX_NAME_LEN]; /* simbolic name */
    > + char path[PPS_MAX_NAME_LEN]; /* path of connected device */
    > + int mode; /* PPS's allowed mode */
    > +
    > + void (*echo)(int source, int event, void *data); /* PPS echo function */
    > +
    > + struct module *owner;
    > + struct device *dev;
    > +};
    > +


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  10. Re: [PATCH 1/7] LinuxPPS core support.

    On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti wrote:
    > This patch adds the kernel side of the PPS support currently named
    > "LinuxPPS".


    > diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c
    > new file mode 100644
    > index 0000000..c25c91c
    > --- /dev/null
    > +++ b/drivers/pps/sysfs.c
    > @@ -0,0 +1,130 @@


    > +void pps_sysfs_remove_source_entry(struct pps_device *pps)
    > +{
    > + /* Delete info files */
    > + sysfs_remove_group(&pps->dev->kobj, &pps_group);
    > +}
    > +
    > +int pps_sysfs_create_source_entry(struct pps_device *pps)
    > +{
    > + int ret;
    > +
    > + /* Create info files */
    > + ret = sysfs_create_group(&pps->dev->kobj, &pps_group);


    Any specific reason you are creating the group by hand, and not assign
    it to the default group in your class? It would will let the core
    handle it for you. The device add uevent to userspace will happen
    before you added the attributes, which is usually not nice.

    Kay
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  11. Re: [PATCH 1/7] LinuxPPS core support.

    On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti wrote:
    > This patch adds the kernel side of the PPS support currently named
    > "LinuxPPS".


    > diff --git a/include/linux/pps.h b/include/linux/pps.h
    > new file mode 100644
    > index 0000000..c455443
    > --- /dev/null
    > +++ b/include/linux/pps.h
    > @@ -0,0 +1,204 @@


    > +/* The main struct */
    > +struct pps_device {
    > + struct pps_source_info info; /* PSS source info */
    > +
    > + struct pps_kparams params; /* PPS's current params */
    > +
    > + __u32 assert_sequence; /* PPS' assert event seq # */
    > + __u32 clear_sequence; /* PPS' clear event seq # */
    > + struct pps_ktime assert_tu;
    > + struct pps_ktime clear_tu;
    > + int current_mode; /* PPS mode at event time */
    > +
    > + int go; /* PPS event is arrived? */
    > + wait_queue_head_t queue; /* PPS event queue */
    > +
    > + unsigned int id; /* PPS source unique ID */
    > + struct cdev cdev;
    > + struct device *dev;
    > + int devno;
    > + struct fasync_struct *async_queue; /* fasync method */
    > + spinlock_t lock;
    > +
    > + atomic_t usage; /* usage count */
    > + wait_queue_head_t usage_queue;
    > +
    > + struct class class_dev;


    Why is an entire class embedded into every device?

    Kay
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  12. Re: [PATCH 1/7] LinuxPPS core support.

    On Fri, Mar 21, 2008 at 04:50:51AM +0100, Kay Sievers wrote:
    > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti wrote:
    > > This patch adds the kernel side of the PPS support currently named
    > > "LinuxPPS".

    >
    > > diff --git a/include/linux/pps.h b/include/linux/pps.h
    > > new file mode 100644
    > > index 0000000..c455443
    > > --- /dev/null
    > > +++ b/include/linux/pps.h
    > > @@ -0,0 +1,204 @@

    >
    > > +/* The main struct */
    > > +struct pps_device {
    > > + struct pps_source_info info; /* PSS source info */
    > > +
    > > + struct pps_kparams params; /* PPS's current params */
    > > +
    > > + __u32 assert_sequence; /* PPS' assert event seq # */
    > > + __u32 clear_sequence; /* PPS' clear event seq # */
    > > + struct pps_ktime assert_tu;
    > > + struct pps_ktime clear_tu;
    > > + int current_mode; /* PPS mode at event time */
    > > +
    > > + int go; /* PPS event is arrived? */
    > > + wait_queue_head_t queue; /* PPS event queue */
    > > +
    > > + unsigned int id; /* PPS source unique ID */
    > > + struct cdev cdev;
    > > + struct device *dev;
    > > + int devno;
    > > + struct fasync_struct *async_queue; /* fasync method */
    > > + spinlock_t lock;
    > > +
    > > + atomic_t usage; /* usage count */
    > > + wait_queue_head_t usage_queue;
    > > +
    > > + struct class class_dev;

    >
    > Why is an entire class embedded into every device?


    Uh! =:-o

    Is that not right? What do you suggest to do?

    Thanks,

    Rodolfo

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  13. Re: [PATCH 1/7] LinuxPPS core support.

    On Fri, Mar 21, 2008 at 04:36:44AM +0100, Kay Sievers wrote:
    > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti wrote:
    > > This patch adds the kernel side of the PPS support currently named
    > > "LinuxPPS".

    >
    > > diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c
    > > new file mode 100644
    > > index 0000000..c25c91c
    > > --- /dev/null
    > > +++ b/drivers/pps/sysfs.c
    > > @@ -0,0 +1,130 @@

    >
    > > +void pps_sysfs_remove_source_entry(struct pps_device *pps)
    > > +{
    > > + /* Delete info files */
    > > + sysfs_remove_group(&pps->dev->kobj, &pps_group);
    > > +}
    > > +
    > > +int pps_sysfs_create_source_entry(struct pps_device *pps)
    > > +{
    > > + int ret;
    > > +
    > > + /* Create info files */
    > > + ret = sysfs_create_group(&pps->dev->kobj, &pps_group);

    >
    > Any specific reason you are creating the group by hand, and not assign
    > it to the default group in your class? It would will let the core
    > handle it for you. The device add uevent to userspace will happen
    > before you added the attributes, which is usually not nice.


    No any specific reason... I just supposed it was the-right-think(TM)!


    Can you please suggest me an URL where I can see how to rework the
    code?

    Ciao,

    Rodolfo

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  14. Re: [PATCH 5/7] PPS: serial clients support.

    On Thu, Mar 20, 2008 at 01:04:00PM -0700, Andrew Morton wrote:
    > On Thu, 6 Mar 2008 13:09:04 +0100
    > Rodolfo Giometti wrote:
    >
    > > Adds support for the PPS sources connected with the CD (Carrier
    > > Detect) pin of a serial port.
    > >
    > > ...
    > >
    > > +#ifdef CONFIG_PPS_CLIENT_UART
    > > +
    > > +static int
    > > +uart_register_pps_port(struct uart_state *state, struct uart_port *port)
    > > +{
    > > + struct tty_driver *drv = port->info->tty->driver;
    > > + int ret;
    > > +
    > > + state->pps_info.owner = THIS_MODULE;
    > > + state->pps_info.dev = port->dev;
    > > + snprintf(state->pps_info.name, PPS_MAX_NAME_LEN, "%s%d",
    > > + drv->driver_name, port->line);
    > > + snprintf(state->pps_info.path, PPS_MAX_NAME_LEN, "/dev/%s%d",
    > > + drv->name, port->line);

    >
    > umm, why are we hard-wiring "/dev" into the kernel source? Is it just for
    > user-friendly printks?


    Yes...

    > > + state->pps_info.mode = PPS_CAPTUREBOTH | \
    > > + PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
    > > + PPS_CANWAIT | PPS_TSFMT_TSPEC;
    > > +
    > > + ret = pps_register_source(&state->pps_info, PPS_CAPTUREBOTH | \
    > > + PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
    > > + if (ret < 0) {
    > > + dev_err(port->dev, "cannot register PPS source \"%s\"\n",
    > > + state->pps_info.path);
    > > + return ret;
    > > + }
    > > + port->pps_source = ret;
    > > + dev_dbg(port->dev, "PPS source #%d \"%s\" added\n",
    > > + port->pps_source, state->pps_info.path);
    > > +
    > > + return 0;
    > > +}
    > > +
    > > +static void
    > > +uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
    > > +{
    > > + pps_unregister_source(port->pps_source);
    > > + dev_dbg(port->dev, "PPS source #%d \"%s\" removed\n",
    > > + port->pps_source, state->pps_info.path);
    > > +}
    > > +
    > > +#else
    > > +
    > > +#define uart_register_pps_port(state, port) do { } while (0)
    > > +#define uart_unregister_pps_port(state, port) do { } while (0)

    >
    > Please never implement in cpp that which can be implemented in C. These
    > should have been static inlines. That's nicer, matches the
    > CONFIG_PPS_CLIENT_UART=y code and provides type checking.


    Are you saying that I should do:

    static inline int
    uart_register_pps_port(struct uart_state *state, struct uart_port *port)
    {
    /* Nop */
    }

    static inline void
    uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
    {
    /* Nop */
    }

    ?

    Ciao,

    Rodolfo

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  15. Re: [PATCH 1/7] LinuxPPS core support.

    On Fri, 2008-03-21 at 11:57 +0100, Rodolfo Giometti wrote:
    > On Fri, Mar 21, 2008 at 04:50:51AM +0100, Kay Sievers wrote:
    > > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti wrote:
    > > > This patch adds the kernel side of the PPS support currently named
    > > > "LinuxPPS".

    > >
    > > > diff --git a/include/linux/pps.h b/include/linux/pps.h
    > > > new file mode 100644
    > > > index 0000000..c455443
    > > > --- /dev/null
    > > > +++ b/include/linux/pps.h
    > > > @@ -0,0 +1,204 @@

    > >
    > > > +/* The main struct */
    > > > +struct pps_device {
    > > > + struct pps_source_info info; /* PSS source info */
    > > > +
    > > > + struct pps_kparams params; /* PPS's current params */
    > > > +
    > > > + __u32 assert_sequence; /* PPS' assert event seq # */
    > > > + __u32 clear_sequence; /* PPS' clear event seq # */
    > > > + struct pps_ktime assert_tu;
    > > > + struct pps_ktime clear_tu;
    > > > + int current_mode; /* PPS mode at event time */
    > > > +
    > > > + int go; /* PPS event is arrived? */
    > > > + wait_queue_head_t queue; /* PPS event queue */
    > > > +
    > > > + unsigned int id; /* PPS source unique ID */
    > > > + struct cdev cdev;
    > > > + struct device *dev;
    > > > + int devno;
    > > > + struct fasync_struct *async_queue; /* fasync method */
    > > > + spinlock_t lock;
    > > > +
    > > > + atomic_t usage; /* usage count */
    > > > + wait_queue_head_t usage_queue;
    > > > +
    > > > + struct class class_dev;

    > >
    > > Why is an entire class embedded into every device?

    >
    > Uh! =:-o
    >
    > Is that not right? What do you suggest to do?


    It looks wrong. Do you use it for anything? I guess, you can just remove
    it.

    Kay

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  16. Re: [PATCH 1/7] LinuxPPS core support.

    On Fri, 2008-03-21 at 11:56 +0100, Rodolfo Giometti wrote:
    > On Fri, Mar 21, 2008 at 04:36:44AM +0100, Kay Sievers wrote:
    > > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti wrote:
    > > > This patch adds the kernel side of the PPS support currently named
    > > > "LinuxPPS".

    > >
    > > > diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c
    > > > new file mode 100644
    > > > index 0000000..c25c91c
    > > > --- /dev/null
    > > > +++ b/drivers/pps/sysfs.c
    > > > @@ -0,0 +1,130 @@

    > >
    > > > +void pps_sysfs_remove_source_entry(struct pps_device *pps)
    > > > +{
    > > > + /* Delete info files */
    > > > + sysfs_remove_group(&pps->dev->kobj, &pps_group);
    > > > +}
    > > > +
    > > > +int pps_sysfs_create_source_entry(struct pps_device *pps)
    > > > +{
    > > > + int ret;
    > > > +
    > > > + /* Create info files */
    > > > + ret = sysfs_create_group(&pps->dev->kobj, &pps_group);

    > >
    > > Any specific reason you are creating the group by hand, and not assign
    > > it to the default group in your class? It would will let the core
    > > handle it for you. The device add uevent to userspace will happen
    > > before you added the attributes, which is usually not nice.

    >
    > No any specific reason... I just supposed it was the-right-think(TM)!
    >
    >
    > Can you please suggest me an URL where I can see how to rework the
    > code?


    You can assign class->dev_attrs the array of attributes, and the driver
    core will create these attributes for all devices that get registered
    with that class. See: drivers/base/core.c :: device_add_attrs().

    Kay

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  17. Re: [PATCH 5/7] PPS: serial clients support.

    On Fri, 21 Mar 2008 12:17:36 +0100 Rodolfo Giometti wrote:

    > > > +#else
    > > > +
    > > > +#define uart_register_pps_port(state, port) do { } while (0)
    > > > +#define uart_unregister_pps_port(state, port) do { } while (0)

    > >
    > > Please never implement in cpp that which can be implemented in C. These
    > > should have been static inlines. That's nicer, matches the
    > > CONFIG_PPS_CLIENT_UART=y code and provides type checking.

    >
    > Are you saying that I should do:
    >
    > static inline int
    > uart_register_pps_port(struct uart_state *state, struct uart_port *port)
    > {
    > /* Nop */
    > }
    >
    > static inline void
    > uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
    > {
    > /* Nop */
    > }
    >
    > ?


    Yes please.
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  18. Re: [PATCH 5/7] PPS: serial clients support.

    On Fri, Mar 21, 2008 at 10:41:25AM -0700, Andrew Morton wrote:
    > On Fri, 21 Mar 2008 12:17:36 +0100 Rodolfo Giometti wrote:
    >
    > > > > +#else
    > > > > +
    > > > > +#define uart_register_pps_port(state, port) do { } while (0)
    > > > > +#define uart_unregister_pps_port(state, port) do { } while (0)
    > > >
    > > > Please never implement in cpp that which can be implemented in C. These
    > > > should have been static inlines. That's nicer, matches the
    > > > CONFIG_PPS_CLIENT_UART=y code and provides type checking.

    > >
    > > Are you saying that I should do:
    > >
    > > static inline int
    > > uart_register_pps_port(struct uart_state *state, struct uart_port *port)
    > > {
    > > /* Nop */
    > > }
    > >
    > > static inline void
    > > uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
    > > {
    > > /* Nop */
    > > }
    > >
    > > ?

    >
    > Yes please.


    Fixed. I'll send a new patch ASAP.

    Rodolfo

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  19. Re: [PATCH 1/7] LinuxPPS core support.

    On Fri, Mar 21, 2008 at 06:00:05PM +0100, Kay Sievers wrote:
    > On Fri, 2008-03-21 at 11:56 +0100, Rodolfo Giometti wrote:
    > > On Fri, Mar 21, 2008 at 04:36:44AM +0100, Kay Sievers wrote:
    > > > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti wrote:
    > > > > This patch adds the kernel side of the PPS support currently named
    > > > > "LinuxPPS".
    > > >
    > > > > diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c
    > > > > new file mode 100644
    > > > > index 0000000..c25c91c
    > > > > --- /dev/null
    > > > > +++ b/drivers/pps/sysfs.c
    > > > > @@ -0,0 +1,130 @@
    > > >
    > > > > +void pps_sysfs_remove_source_entry(struct pps_device *pps)
    > > > > +{
    > > > > + /* Delete info files */
    > > > > + sysfs_remove_group(&pps->dev->kobj, &pps_group);
    > > > > +}
    > > > > +
    > > > > +int pps_sysfs_create_source_entry(struct pps_device *pps)
    > > > > +{
    > > > > + int ret;
    > > > > +
    > > > > + /* Create info files */
    > > > > + ret = sysfs_create_group(&pps->dev->kobj, &pps_group);
    > > >
    > > > Any specific reason you are creating the group by hand, and not assign
    > > > it to the default group in your class? It would will let the core
    > > > handle it for you. The device add uevent to userspace will happen
    > > > before you added the attributes, which is usually not nice.

    > >
    > > No any specific reason... I just supposed it was the-right-think(TM)!
    > >
    > >
    > > Can you please suggest me an URL where I can see how to rework the
    > > code?

    >
    > You can assign class->dev_attrs the array of attributes, and the driver
    > core will create these attributes for all devices that get registered
    > with that class. See: drivers/base/core.c :: device_add_attrs().


    Fixed, I'll provide a new patch ASAP.

    Thanks,

    Rodolfo

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  20. Re: [PATCH 1/7] LinuxPPS core support.

    On Fri, Mar 21, 2008 at 04:50:51AM +0100, Kay Sievers wrote:
    > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti wrote:
    > > This patch adds the kernel side of the PPS support currently named
    > > "LinuxPPS".

    >
    > > diff --git a/include/linux/pps.h b/include/linux/pps.h
    > > new file mode 100644
    > > index 0000000..c455443
    > > --- /dev/null
    > > +++ b/include/linux/pps.h
    > > @@ -0,0 +1,204 @@

    >
    > > +/* The main struct */
    > > +struct pps_device {
    > > + struct pps_source_info info; /* PSS source info */
    > > +
    > > + struct pps_kparams params; /* PPS's current params */
    > > +
    > > + __u32 assert_sequence; /* PPS' assert event seq # */
    > > + __u32 clear_sequence; /* PPS' clear event seq # */
    > > + struct pps_ktime assert_tu;
    > > + struct pps_ktime clear_tu;
    > > + int current_mode; /* PPS mode at event time */
    > > +
    > > + int go; /* PPS event is arrived? */
    > > + wait_queue_head_t queue; /* PPS event queue */
    > > +
    > > + unsigned int id; /* PPS source unique ID */
    > > + struct cdev cdev;
    > > + struct device *dev;
    > > + int devno;
    > > + struct fasync_struct *async_queue; /* fasync method */
    > > + spinlock_t lock;
    > > +
    > > + atomic_t usage; /* usage count */
    > > + wait_queue_head_t usage_queue;
    > > +
    > > + struct class class_dev;

    >
    > Why is an entire class embedded into every device?


    Fixed, I'll provide a new patch ASAP.

    Thanks,

    Rodolfo

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    Linux Device Driver giometti@gnudd.com
    Embedded Systems giometti@linux.it
    UNIX programming phone: +39 349 2432127
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