LinuxPPS (RESUBMIT 3): the PPS Linux implementation. - Kernel

This is a discussion on LinuxPPS (RESUBMIT 3): 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 3): the PPS Linux implementation.

  1. LinuxPPS (RESUBMIT 3): 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 | 330 +++++++++++++++++++++++++++++++++
    b/drivers/pps/pps.c | 335 ++++++++++++++++++++++++++++++++++
    b/drivers/pps/sysfs.c | 103 ++++++++++
    b/drivers/serial/8250.c | 2
    b/drivers/serial/serial_core.c | 131 ++++++++++---
    b/include/linux/Kbuild | 1
    b/include/linux/parport.h | 13 +
    b/include/linux/pps.h | 203 ++++++++++++++++++++
    b/include/linux/serial_core.h | 31 ++-
    drivers/pps/Kconfig | 2
    drivers/pps/Makefile | 1
    drivers/pps/clients/Kconfig | 20 ++
    30 files changed, 2083 insertions(+), 45 deletions(-)


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

    Adds support for the PPS sources connected with the CD (Carrier
    Detect) pin of a serial port.

    Signed-off-by: Rodolfo Giometti
    ---
    drivers/pps/clients/Kconfig | 10 +++
    drivers/serial/8250.c | 2 +
    drivers/serial/serial_core.c | 131 ++++++++++++++++++++++++++++++++----------
    include/linux/serial_core.h | 30 ++++++++--
    4 files changed, 136 insertions(+), 37 deletions(-)

    diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
    index 60b83be..517c338 100644
    --- a/drivers/pps/clients/Kconfig
    +++ b/drivers/pps/clients/Kconfig
    @@ -15,4 +15,14 @@ config PPS_CLIENT_KTIMER
    This driver can also be built as a module. If so, the module
    will be called ktimer.ko.

    +comment "UART serial support (forced off)"
    + depends on ! (SERIAL_CORE != n && !(PPS = m && SERIAL_CORE = y))
    +
    +config PPS_CLIENT_UART
    + bool "UART serial support"
    + depends on SERIAL_CORE != n && !(PPS = m && SERIAL_CORE = y)
    + help
    + If you say yes here you get support for a PPS source connected
    + with the CD (Carrier Detect) pin of your serial port.
    +
    endif
    diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
    index 77f7a7f..880cbeb 100644
    --- a/drivers/serial/8250.c
    +++ b/drivers/serial/8250.c
    @@ -2119,6 +2119,8 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
    up->ier |= UART_IER_MSI;
    if (up->capabilities & UART_CAP_UUE)
    up->ier |= UART_IER_UUE | UART_IER_RTOIE;
    + if (up->port.flags & UPF_HARDPPS_CD)
    + up->ier |= UART_IER_MSI; /* enable interrupts */

    serial_out(up, UART_IER, up->ier);

    diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
    index 0f5a179..5a97e63 100644
    --- a/drivers/serial/serial_core.c
    +++ b/drivers/serial/serial_core.c
    @@ -33,6 +33,7 @@
    #include /* for serial_state and serial_icounter_struct */
    #include
    #include
    +#include

    #include
    #include
    @@ -58,8 +59,7 @@ static struct lock_class_key port_lock_key;
    #define uart_console(port) (0)
    #endif

    -static void uart_change_speed(struct uart_state *state,
    - struct ktermios *old_termios);
    +static void uart_change_speed(struct uart_state *state, struct ktermios *old_termios);
    static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
    static void uart_change_pm(struct uart_state *state, int pm_state);

    @@ -130,8 +130,8 @@ uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
    spin_unlock_irqrestore(&port->lock, flags);
    }

    -#define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
    -#define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
    +#define uart_set_mctrl(port,set) uart_update_mctrl(port,set,0)
    +#define uart_clear_mctrl(port,clear) uart_update_mctrl(port,0,clear)

    /*
    * Startup the port. This will be called once per open. All calls
    @@ -291,7 +291,7 @@ uart_update_timeout(struct uart_port *port, unsigned int cflag,
    break;
    default:
    bits = 10;
    - break; /* CS8 */
    + break; // CS8
    }

    if (cflag & CSTOPB)
    @@ -372,8 +372,7 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
    */
    termios->c_cflag &= ~CBAUD;
    if (old) {
    - baud = tty_termios_baud_rate(old);
    - tty_termios_encode_baud_rate(termios, baud, baud);
    + termios->c_cflag |= old->c_cflag & CBAUD;
    old = NULL;
    continue;
    }
    @@ -382,7 +381,7 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
    * As a last resort, if the quotient is zero,
    * default to 9600 bps
    */
    - tty_termios_encode_baud_rate(termios, 9600, 9600);
    + termios->c_cflag |= B9600;
    }

    return 0;
    @@ -635,6 +634,63 @@ static int uart_get_info(struct uart_state *state,
    return 0;
    }

    +#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);
    +
    + 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
    +
    +static inline int
    +uart_register_pps_port(struct uart_state *state, struct uart_port *port)
    +{
    + return 0;
    +}
    +
    +static inline void
    +uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
    +{
    + /* Nop */
    +}
    +
    +#endif /* CONFIG_PPS_CLIENT_UART */
    +
    static int uart_set_info(struct uart_state *state,
    struct serial_struct __user *newinfo)
    {
    @@ -789,8 +845,7 @@ static int uart_set_info(struct uart_state *state,
    * We failed anyway.
    */
    retval = -EBUSY;
    - /* Added to return the correct error -Ram Gupta */
    - goto exit;
    + goto exit; // Added to return the correct error -Ram Gupta
    }
    }

    @@ -810,11 +865,19 @@ 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,
    @@ -1139,8 +1202,7 @@ uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
    return ret;
    }

    -static void uart_set_termios(struct tty_struct *tty,
    - struct ktermios *old_termios)
    +static void uart_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
    {
    struct uart_state *state = tty->driver_data;
    unsigned long flags;
    @@ -1464,8 +1526,9 @@ uart_block_til_ready(struct file *filp, struct uart_state *state)
    */
    if ((filp->f_flags & O_NONBLOCK) ||
    (info->tty->termios->c_cflag & CLOCAL) ||
    - (info->tty->flags & (1 << TTY_IO_ERROR)))
    + (info->tty->flags & (1 << TTY_IO_ERROR))) {
    break;
    + }

    /*
    * Set DTR to allow modem to know we're waiting. Do
    @@ -1553,8 +1616,8 @@ static struct uart_state *uart_get(struct uart_driver *drv, int line)
    }

    /*
    - * calls to uart_open are serialised by the BKL in
    - * fs/char_dev.c:chrdev_open()
    + * In 2.4.5, calls to uart_open are serialised by the BKL in
    + * linux/fs/devices.c:chrdev_open()
    * Note that if this fails, then uart_close() _will_ be called.
    *
    * In time, we want to scrap the "opening nonpresent ports"
    @@ -1684,7 +1747,8 @@ static int uart_line_info(char *buf, struct uart_driver *drv, int i)
    return ret + 1;
    }

    - if (capable(CAP_SYS_ADMIN)) {
    + if(capable(CAP_SYS_ADMIN))
    + {
    mutex_lock(&state->mutex);
    pm_state = state->pm_state;
    if (pm_state)
    @@ -1711,11 +1775,11 @@ static int uart_line_info(char *buf, struct uart_driver *drv, int i)
    ret += sprintf(buf + ret, " oe:%d",
    port->icount.overrun);

    -#define INFOBIT(bit, str) \
    +#define INFOBIT(bit,str) \
    if (port->mctrl & (bit)) \
    strncat(stat_buf, (str), sizeof(stat_buf) - \
    strlen(stat_buf) - 2)
    -#define STATBIT(bit, str) \
    +#define STATBIT(bit,str) \
    if (status & (bit)) \
    strncat(stat_buf, (str), sizeof(stat_buf) - \
    strlen(stat_buf) - 2)
    @@ -1979,7 +2043,6 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)

    if (state->info && state->info->flags & UIF_INITIALIZED) {
    const struct uart_ops *ops = port->ops;
    - int tries;

    state->info->flags = (state->info->flags & ~UIF_INITIALIZED)
    | UIF_SUSPENDED;
    @@ -1993,14 +2056,9 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
    /*
    * Wait for the transmitter to empty.
    */
    - for (tries = 3; !ops->tx_empty(port) && tries; tries--)
    + while (!ops->tx_empty(port)) {
    msleep(10);
    - if (!tries)
    - printk(KERN_ERR "%s%s%s%d: Unable to drain "
    - "transmitter\n",
    - port->dev ? port->dev->bus_id : "",
    - port->dev ? ": " : "",
    - drv->dev_name, port->line);
    + }

    ops->shutdown(port);
    }
    @@ -2037,6 +2095,8 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
    }
    port->suspended = 0;

    + uart_change_pm(state, 0);
    +
    /*
    * Re-enable the console device after suspending.
    */
    @@ -2055,7 +2115,6 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
    if (state->info && state->info->tty && termios.c_cflag == 0)
    termios = *state->info->tty->termios;

    - uart_change_pm(state, 0);
    port->ops->set_termios(port, &termios, NULL);
    console_start(port->cons);
    }
    @@ -2064,7 +2123,6 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
    const struct uart_ops *ops = port->ops;
    int ret;

    - uart_change_pm(state, 0);
    ops->set_mctrl(port, 0);
    ret = ops->startup(port);
    if (ret == 0) {
    @@ -2148,6 +2206,12 @@ 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;

    @@ -2158,11 +2222,10 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,

    /*
    * Ensure that the modem control lines are de-activated.
    - * keep the DTR setting that is set in uart_set_options()
    * We probably don't need a spinlock around this, but
    */
    spin_lock_irqsave(&port->lock, flags);
    - port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
    + port->ops->set_mctrl(port, 0);
    spin_unlock_irqrestore(&port->lock, 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);
    diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
    index 289942f..0f8fbd4 100644
    --- a/include/linux/serial_core.h
    +++ b/include/linux/serial_core.h
    @@ -166,6 +166,7 @@
    #include
    #include
    #include
    +#include

    struct uart_port;
    struct uart_info;
    @@ -245,6 +246,9 @@ struct uart_port {
    unsigned char regshift; /* reg offset shift */
    unsigned char iotype; /* io access style */
    unsigned char unused1;
    +#ifdef CONFIG_PPS_CLIENT_UART
    + int pps_source; /* PPS source ID */
    +#endif

    #define UPIO_PORT (0)
    #define UPIO_HUB6 (1)
    @@ -289,7 +293,8 @@ struct uart_port {
    #define UPF_IOREMAP ((__force upf_t) (1 << 31))

    #define UPF_CHANGE_MASK ((__force upf_t) (0x17fff))
    -#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
    +#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY\
    + |UPF_HARDPPS_CD))

    unsigned int mctrl; /* current modem ctrl settings */
    unsigned int timeout; /* character-based timeout */
    @@ -322,6 +327,10 @@ struct uart_state {
    struct uart_info *info;
    struct uart_port *port;

    +#ifdef CONFIG_PPS_CLIENT_UART
    + struct pps_source_info pps_info;
    +#endif
    +
    struct mutex mutex;
    };

    @@ -486,13 +495,22 @@ uart_handle_dcd_change(struct uart_port *port, unsigned int status)
    {
    struct uart_info *info = port->info;

    - port->icount.dcd++;
    -
    -#ifdef CONFIG_HARD_PPS
    - if ((port->flags & UPF_HARDPPS_CD) && status)
    - hardpps();
    +#ifdef CONFIG_PPS_CLIENT_UART
    + if (port->flags & UPF_HARDPPS_CD) {
    + if (status) {
    + pps_event(port->pps_source, PPS_CAPTUREASSERT, port);
    + dev_dbg(port->dev, "PPS assert at %lu on source #%d\n",
    + jiffies, port->pps_source);
    + } else {
    + pps_event(port->pps_source, PPS_CAPTURECLEAR, port);
    + dev_dbg(port->dev, "PPS clear at %lu on source #%d\n",
    + jiffies, port->pps_source);
    + }
    + }
    #endif

    + port->icount.dcd++;
    +
    if (info->flags & UIF_CHECK_CD) {
    if (status)
    wake_up_interruptible(&info->open_wait);
    --
    1.5.4.3

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  3. [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 | 330 ++++++++++++++++++++++++++++++++++
    drivers/pps/pps.c | 335 +++++++++++++++++++++++++++++++++++
    drivers/pps/sysfs.c | 103 +++++++++++
    include/linux/Kbuild | 1 +
    include/linux/pps.h | 202 +++++++++++++++++++++
    13 files changed, 1267 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..8cba1d9
    --- /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..2b25a48
    --- /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 90dcbbc..a67d624 100644
    --- a/MAINTAINERS
    +++ b/MAINTAINERS
    @@ -3171,6 +3171,13 @@ 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..6c72e2e
    --- /dev/null
    +++ b/drivers/pps/kapi.c
    @@ -0,0 +1,330 @@
    +/*
    + * 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(pps_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
    + */
    +
    +/* pps_get_source - find a PPS source
    + *
    + * source: the PPS source ID.
    + *
    + * This function is used to find an already registered PPS source into the
    + * system.
    + *
    + * The function returns NULL if found nothing, otherwise it returns a pointer
    + * to the PPS source data struct (the refcounter is incremented by 1).
    + */
    +
    +struct pps_device *pps_get_source(int source)
    +{
    + struct pps_device *pps;
    + unsigned long flags;
    +
    + spin_lock_irqsave(&pps_idr_lock, flags);
    +
    + pps = idr_find(&pps_idr, source);
    + if (pps != NULL)
    + atomic_inc(&pps->usage);
    +
    + spin_unlock_irqrestore(&pps_idr_lock, flags);
    +
    + return pps;
    +}
    +
    +/* pps_put_source - free the PPS source data
    + *
    + * pps: a pointer to the PPS source.
    + *
    + * This function is used to free a PPS data struct if its refcount is 0.
    + */
    +
    +void pps_put_source(struct pps_device *pps)
    +{
    + unsigned long flags;
    +
    + spin_lock_irqsave(&pps_idr_lock, flags);
    + BUG_ON(atomic_read(&pps->usage) == 0);
    +
    + if (!atomic_dec_and_test(&pps->usage)) {
    + pps = NULL;
    + goto exit;
    + }
    +
    + /* No more reference to the PPS source. We can safely remove the
    + * PPS data struct.
    + */
    + idr_remove(&pps_idr, pps->id);
    +
    +exit:
    + spin_unlock_irqrestore(&pps_idr_lock, flags);
    + kfree(pps);
    +}
    +
    +/* pps_register_source - add a PPS source in the system
    + *
    + * info: the PPS info struct
    + * default_params: the default PPS parameters of the new source
    + *
    + * This function is used to add a new PPS source in the system. The new
    + * source is described by info's fields and it will have, as default PPS
    + * parameters, the ones specified into default_params.
    + *
    + * The function returns, in case of success, the PPS source ID.
    + */
    +
    +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(&pps_idr_lock);
    + err = idr_get_new(&pps_idr, pps, &id);
    + spin_unlock_irq(&pps_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, 1);
    +
    + /* 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;
    + }
    +
    + pr_info("new PPS source %s at ID %d\n", info->name, id);
    +
    + return id;
    +
    +free_idr:
    + spin_lock_irq(&pps_idr_lock);
    + idr_remove(&pps_idr, id);
    + spin_unlock_irq(&pps_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);
    +
    +/* pps_unregister_source - remove a PPS source from the system
    + *
    + * source: the PPS source ID
    + *
    + * This function is used to remove a previously registered PPS source from
    + * the system.
    + */
    +
    +void pps_unregister_source(int source)
    +{
    + struct pps_device *pps;
    +
    + spin_lock_irq(&pps_idr_lock);
    + pps = idr_find(&pps_idr, source);
    +
    + if (!pps) {
    + BUG();
    + spin_unlock_irq(&pps_idr_lock);
    + return;
    + }
    + spin_unlock_irq(&pps_idr_lock);
    +
    + pps_unregister_cdev(pps);
    + pps_put_source(pps);
    +}
    +EXPORT_SYMBOL(pps_unregister_source);
    +
    +/* pps_event - register a PPS event into the system
    + *
    + * source: the PPS source ID
    + * event: the event type
    + * data: userdef pointer
    + *
    + * This function is used by each PPS client in order to register a new
    + * PPS event into the system (it's usually called inside an IRQ handler).
    + *
    + * If an echo function is associated with the PPS source it will be called
    + * as:
    + * pps->info.echo(source, event, data);
    + */
    +
    +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;
    + }
    +
    + pps = pps_get_source(source);
    + if (!pps)
    + return;
    +
    + pr_debug("PPS event on source %d at %llu.%06u\n",
    + pps->id, (unsigned long long) 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 */
    + pps_put_source(pps);
    +}
    +EXPORT_SYMBOL(pps_event);
    diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
    new file mode 100644
    index 0000000..a46f8f4
    --- /dev/null
    +++ b/drivers/pps/pps.c
    @@ -0,0 +1,335 @@
    +/*
    + * 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",
    + (long long) 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;
    +
    + found = pps_get_source(pps->id) != 0;
    + 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 */
    + pps_put_source(pps);
    +
    + 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;
    + }
    + pps_class->dev_attrs = pps_attrs;
    +
    + 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..0520f62
    --- /dev/null
    +++ b/drivers/pps/sysfs.c
    @@ -0,0 +1,103 @@
    +/*
    + * 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",
    + (long long) 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",
    + (long long) 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);
    +
    +struct device_attribute pps_attrs[] = {
    + __ATTR(assert, S_IRUGO, pps_show_assert, NULL),
    + __ATTR(clear, S_IRUGO, pps_show_clear, NULL),
    + __ATTR(mode, S_IRUGO, pps_show_mode, NULL),
    + __ATTR(echo, S_IRUGO, pps_show_echo, NULL),
    + __ATTR(name, S_IRUGO, pps_show_name, NULL),
    + __ATTR(path, S_IRUGO, pps_show_path, NULL),
    +};
    diff --git a/include/linux/Kbuild b/include/linux/Kbuild
    index 9cdd12a..0dd702c 100644
    --- a/include/linux/Kbuild
    +++ b/include/linux/Kbuild
    @@ -294,6 +294,7 @@ 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..83a23d2
    --- /dev/null
    +++ b/include/linux/pps.h
    @@ -0,0 +1,202 @@
    +/*
    + * 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_
    +
    +#define PPS_VERSION "5.1.0"
    +#define PPS_MAX_SOURCES 16 /* should be enough... */
    +
    +/* 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
    +
    +/*
    + * 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 */
    +};
    +
    +/*
    + * Global variables
    + */
    +
    +extern spinlock_t pps_idr_lock;
    +extern struct idr pps_idr;
    +
    +extern struct device_attribute pps_attrs[];
    +
    +/*
    + * Exported functions
    + */
    +
    +struct pps_device *pps_get_source(int source);
    +extern void pps_put_source(struct pps_device *pps);
    +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);
    +
    +#endif /* __KERNEL__ */
    +
    +#endif /* _PPS_H_ */
    --
    1.5.4.3

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  4. Re: LinuxPPS (RESUBMIT 3): the PPS Linux implementation.

    On Thu, Apr 10, 2008 at 05:15:53PM +0200, 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.


    Thank you for keeping at this. Great work.

    --
    Len Sorensen
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  5. Re: [PATCH 5/7] PPS: serial clients support.

    On Thu, Apr 10, 2008 at 04:28:12PM +0100, Alan Cox wrote:
    > On Thu, 10 Apr 2008 17:15:58 +0200
    > Rodolfo Giometti wrote:
    >
    > > Adds support for the PPS sources connected with the CD (Carrier
    > > Detect) pin of a serial port.

    >
    > Ok why does this need to hack the driver layer ?
    >
    > > -static void uart_change_speed(struct uart_state *state,
    > > - struct ktermios *old_termios);
    > > +static void uart_change_speed(struct uart_state *state, struct ktermios *old_termios);

    >
    > NAK. Please remove random formatting changes


    Sorry, this patch is wrong! I'll re-submit the right code. '-_-

    Thanks,

    Rodolfo

    --

    GNU/Linux Solutions e-mail: giometti@enneenne.com
    Linux Device Driver giometti@linux.it
    Embedded Systems phone: +39 349 2432127
    UNIX programming skype: rodolfo.giometti
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  6. Re: [PATCH 5/7] PPS: serial clients support.

    On Thu, 10 Apr 2008 17:15:58 +0200
    Rodolfo Giometti wrote:

    > Adds support for the PPS sources connected with the CD (Carrier
    > Detect) pin of a serial port.


    Ok why does this need to hack the driver layer ?

    > -static void uart_change_speed(struct uart_state *state,
    > - struct ktermios *old_termios);
    > +static void uart_change_speed(struct uart_state *state, struct ktermios *old_termios);


    NAK. Please remove random formatting changes

    > -#define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
    > -#define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
    > +#define uart_set_mctrl(port,set) uart_update_mctrl(port,set,0)
    > +#define uart_clear_mctrl(port,clear) uart_update_mctrl(port,0,clear)


    Ditto

    >
    > /*
    > * Startup the port. This will be called once per open. All calls
    > @@ -291,7 +291,7 @@ uart_update_timeout(struct uart_port *port, unsigned int cflag,
    > break;
    > default:
    > bits = 10;
    > - break; /* CS8 */
    > + break; // CS8


    Ditto

    > - baud = tty_termios_baud_rate(old);
    > - tty_termios_encode_baud_rate(termios, baud, baud);
    > + termios->c_cflag |= old->c_cflag & CBAUD;


    NAK. Breaks the tty layer code

    > old = NULL;
    > continue;
    > }
    > @@ -382,7 +381,7 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
    > * As a last resort, if the quotient is zero,
    > * default to 9600 bps
    > */
    > - tty_termios_encode_baud_rate(termios, 9600, 9600);
    > + termios->c_cflag |= B9600;


    NAK breaks the tty layer code

    > +#ifdef CONFIG_PPS_CLIENT_UART


    wrong layer - this means only some ports will work.


    > @@ -789,8 +845,7 @@ static int uart_set_info(struct uart_state *state,
    > * We failed anyway.
    > */
    > retval = -EBUSY;
    > - /* Added to return the correct error -Ram Gupta */
    > - goto exit;
    > + goto exit; // Added to return the correct error -Ram Gupta


    More format mangling

    > + /* PPS support enabled/disabled? */
    > + if ((old_flags & UPF_HARDPPS_CD) != (new_flags & UPF_HARDPPS_CD)) {


    How is this flag set ?


    > -static void uart_set_termios(struct tty_struct *tty,
    > - struct ktermios *old_termios)
    > +static void uart_set_termios(struct tty_struct *tty, struct ktermios *old_termios)


    NAK - more format mangling

    > {
    > struct uart_state *state = tty->driver_data;
    > unsigned long flags;
    > @@ -1464,8 +1526,9 @@ uart_block_til_ready(struct file *filp, struct uart_state *state)
    > */
    > if ((filp->f_flags & O_NONBLOCK) ||
    > (info->tty->termios->c_cflag & CLOCAL) ||
    > - (info->tty->flags & (1 << TTY_IO_ERROR)))
    > + (info->tty->flags & (1 << TTY_IO_ERROR))) {


    And more - and so it goes on. Please clean up the mess and submit a
    proposal which is just the relevant changes so it can be read. Then we
    can talk about putting it in the right place.

    My guess is that PPS like FIR should be a line discipline and they both
    and a couple of other cases want the tty layer to grow

    tty->ops->report_event();

    and
    tty->ops->set_event_mask();

    for nicer ways to monitor modem bits in the ldisc.

    Alan
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