- 根目录:
- drivers
- pps
- kapi.c
/*
* kernel API
*
*
* Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it>
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/pps_kernel.h>
#include <linux/slab.h>
#include "kc.h"
/*
* 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;
}
static void pps_echo_client_default(struct pps_device *pps, int event,
void *data)
{
dev_info(pps->dev, "echo %s %s\n",
event & PPS_CAPTUREASSERT ? "assert" : "",
event & PPS_CAPTURECLEAR ? "clear" : "");
}
/*
* Exported functions
*/
/* 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 device. Otherwise NULL.
*/
struct pps_device *pps_register_source(struct pps_source_info *info,
int default_params)
{
struct pps_device *pps;
int err;
/* Sanity checks */
if ((info->mode & default_params) != default_params) {
pr_err("%s: unsupported default parameters\n",
info->name);
err = -EINVAL;
goto pps_register_source_exit;
}
if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
pr_err("%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;
}
/* These initializations must be done before calling idr_alloc()
* in order to avoid reces into pps_event().
*/
pps->params.api_version = PPS_API_VERS;
pps->params.mode = default_params;
pps->info = *info;
/* check for default echo function */
if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) &&
pps->info.echo == NULL)
pps->info.echo = pps_echo_client_default;
init_waitqueue_head(&pps->queue);
spin_lock_init(&pps->lock);
/* Create the char device */
err = pps_register_cdev(pps);
if (err < 0) {
pr_err("%s: unable to create char device\n",
info->name);
goto kfree_pps;
}
dev_info(pps->dev, "new PPS source %s\n", info->name);
return pps;
kfree_pps:
kfree(pps);
pps_register_source_exit:
pr_err("%s: unable to register source\n", info->name);
return NULL;
}
EXPORT_SYMBOL(pps_register_source);
/* pps_unregister_source - remove a PPS source from the system
* @pps: the PPS source
*
* This function is used to remove a previously registered PPS source from
* the system.
*/
void pps_unregister_source(struct pps_device *pps)
{
pps_kc_remove(pps);
pps_unregister_cdev(pps);
/* don't have to kfree(pps) here because it will be done on
* device destruction */
}
EXPORT_SYMBOL(pps_unregister_source);
/* pps_event - register a PPS event into the system
* @pps: the PPS device
* @ts: the event timestamp
* @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 device it will be called
* as:
* pps->info.echo(pps, event, data);
*/
void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
void *data)
{
unsigned long flags;
int captured = 0;
struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 };
/* check event type */
BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0);
dev_dbg(pps->dev, "PPS event at %ld.%09ld\n",
ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
timespec_to_pps_ktime(&ts_real, ts->ts_real);
spin_lock_irqsave(&pps->lock, flags);
/* Must call the echo function? */
if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
pps->info.echo(pps, event, data);
/* Check the event */
pps->current_mode = pps->params.mode;
if (event & pps->params.mode & PPS_CAPTUREASSERT) {
/* We have to add an offset? */
if (pps->params.mode & PPS_OFFSETASSERT)
pps_add_offset(&ts_real,
&pps->params.assert_off_tu);
/* Save the time stamp */
pps->assert_tu = ts_real;
pps->assert_sequence++;
dev_dbg(pps->dev, "capture assert seq #%u\n",
pps->assert_sequence);
captured = ~0;
}
if (event & pps->params.mode & PPS_CAPTURECLEAR) {
/* We have to add an offset? */
if (pps->params.mode & PPS_OFFSETCLEAR)
pps_add_offset(&ts_real,
&pps->params.clear_off_tu);
/* Save the time stamp */
pps->clear_tu = ts_real;
pps->clear_sequence++;
dev_dbg(pps->dev, "capture clear seq #%u\n",
pps->clear_sequence);
captured = ~0;
}
pps_kc_event(pps, ts, event);
/* Wake up if captured something */
if (captured) {
pps->last_ev++;
wake_up_interruptible_all(&pps->queue);
kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
}
spin_unlock_irqrestore(&pps->lock, flags);
}
EXPORT_SYMBOL(pps_event);