Adds support for the PPS sources connected with the interrupt pin of a
parallel port.

Signed-off-by: Rodolfo Giometti
---
drivers/char/lp.c | 61 +++++++++++++++++++++++++++++++++++++++++++
drivers/pps/clients/Kconfig | 10 +++++++
include/linux/parport.h | 12 ++++++++
3 files changed, 83 insertions(+), 0 deletions(-)

diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index 60ac642..b201fed 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -746,6 +746,27 @@ static struct console lpcons = {

#endif /* console on line printer */

+/* Support for PPS signal on the line printer */
+
+#ifdef CONFIG_PPS_CLIENT_LP
+
+static void lp_pps_echo(int source, int event, void *data)
+{
+ struct parport *port = data;
+ unsigned char status = parport_read_status(port);
+
+ /* echo event via SEL bit */
+ parport_write_control(port,
+ parport_read_control(port) | PARPORT_CONTROL_SELECT);
+
+ /* signal no event */
+ if ((status & PARPORT_STATUS_ACK) != 0)
+ parport_write_control(port,
+ parport_read_control(port) & ~PARPORT_CONTROL_SELECT);
+}
+
+#endif
+
/* --- initialisation code ------------------------------------- */

static int parport_nr[LP_NO] = { [0 ... LP_NO-1] = LP_PARPORT_UNSPEC };
@@ -816,6 +837,38 @@ static int lp_register(int nr, struct parport *port)
}
#endif

+#ifdef CONFIG_PPS_CLIENT_LP
+ port->pps_info.owner = THIS_MODULE;
+ port->pps_info.dev = port->dev;
+ snprintf(port->pps_info.path, PPS_MAX_NAME_LEN, "/dev/lp%d", nr);
+
+ /* No PPS support if lp port has no IRQ line */
+ if (port->irq != PARPORT_IRQ_NONE) {
+ strncpy(port->pps_info.name, port->name, PPS_MAX_NAME_LEN);
+
+ port->pps_info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT | \
+ PPS_ECHOASSERT | \
+ PPS_CANWAIT | PPS_TSFMT_TSPEC;
+
+ port->pps_info.echo = lp_pps_echo;
+
+ port->pps_source = pps_register_source(&(port->pps_info),
+ PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
+ if (port->pps_source < 0)
+ dev_err(port->dev,
+ "cannot register PPS source \"%s\"\n",
+ port->pps_info.path);
+ else
+ dev_info(port->dev, "PPS source #%d \"%s\" added\n",
+ port->pps_source, port->pps_info.path);
+ } else {
+ port->pps_source = -1;
+ dev_err(port->dev, "PPS support disabled because port \"%s\" "
+ "is in polling mode\n",
+ port->pps_info.path);
+ }
+#endif
+
return 0;
}

@@ -858,6 +911,14 @@ static void lp_detach (struct parport *port)
console_registered = NULL;
}
#endif /* CONFIG_LP_CONSOLE */
+
+#ifdef CONFIG_PPS_CLIENT_LP
+ if (port->pps_source >= 0) {
+ pps_unregister_source(port->pps_source);
+ dev_dbg(port->dev, "PPS source #%d \"%s\" removed\n",
+ port->pps_source, port->pps_info.path);
+ }
+#endif
}

static struct parport_driver lp_driver = {
diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
index 517c338..09ba5c3 100644
--- a/drivers/pps/clients/Kconfig
+++ b/drivers/pps/clients/Kconfig
@@ -25,4 +25,14 @@ config PPS_CLIENT_UART
If you say yes here you get support for a PPS source connected
with the CD (Carrier Detect) pin of your serial port.

+comment "Parallel printer support (forced off)"
+ depends on !( PRINTER != n && !(PPS = m && PRINTER = y))
+
+config PPS_CLIENT_LP
+ bool "Parallel printer support"
+ depends on PRINTER != n && !(PPS = m && PRINTER = y)
+ help
+ If you say yes here you get support for a PPS source connected
+ with the interrupt pin of your parallel port.
+
endif
diff --git a/include/linux/parport.h b/include/linux/parport.h
index d1ad546..501a9dc 100644
--- a/include/linux/parport.h
+++ b/include/linux/parport.h
@@ -100,6 +100,7 @@ typedef enum {
#include
#include
#include
+#include
#include
#include
#include
@@ -328,6 +329,11 @@ struct parport {

struct list_head full_list;
struct parport *slaves[3];
+
+#ifdef CONFIG_PPS_CLIENT_LP
+ struct pps_source_info pps_info;
+ int pps_source; /* PPS source ID */
+#endif
};

#define DEFAULT_SPIN_TIME 500 /* us */
@@ -516,6 +522,12 @@ extern int parport_daisy_select (struct parport *port, int daisy, int mode);
/* Lowlevel drivers _can_ call this support function to handle irqs. */
static inline void parport_generic_irq(struct parport *port)
{
+#ifdef CONFIG_PPS_CLIENT_LP
+ pps_event(port->pps_source, PPS_CAPTUREASSERT, port);
+ dev_dbg(port->dev, "PPS assert at %lu on source #%d\n",
+ jiffies, port->pps_source);
+#endif
+
parport_ieee1284_interrupt (port);
read_lock(&port->cad_lock);
if (port->cad && port->cad->irq_func)
--
1.5.4.3

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