mirror of
https://github.com/torvalds/linux.git
synced 2024-11-18 10:01:43 +00:00
717c033669
Add an optional feature of PPSAPI, kernel consumer support, which uses the added hardpps() function. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
123 lines
3.8 KiB
C
123 lines
3.8 KiB
C
/*
|
|
* PPS kernel consumer API
|
|
*
|
|
* Copyright (C) 2009-2010 Alexander Gordeev <lasaine@lvk.cs.msu.su>
|
|
*
|
|
* 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/device.h>
|
|
#include <linux/init.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/pps_kernel.h>
|
|
|
|
#include "kc.h"
|
|
|
|
/*
|
|
* Global variables
|
|
*/
|
|
|
|
/* state variables to bind kernel consumer */
|
|
DEFINE_SPINLOCK(pps_kc_hardpps_lock);
|
|
/* PPS API (RFC 2783): current source and mode for kernel consumer */
|
|
struct pps_device *pps_kc_hardpps_dev; /* unique pointer to device */
|
|
int pps_kc_hardpps_mode; /* mode bits for kernel consumer */
|
|
|
|
/* pps_kc_bind - control PPS kernel consumer binding
|
|
* @pps: the PPS source
|
|
* @bind_args: kernel consumer bind parameters
|
|
*
|
|
* This function is used to bind or unbind PPS kernel consumer according to
|
|
* supplied parameters. Should not be called in interrupt context.
|
|
*/
|
|
int pps_kc_bind(struct pps_device *pps, struct pps_bind_args *bind_args)
|
|
{
|
|
/* Check if another consumer is already bound */
|
|
spin_lock_irq(&pps_kc_hardpps_lock);
|
|
|
|
if (bind_args->edge == 0)
|
|
if (pps_kc_hardpps_dev == pps) {
|
|
pps_kc_hardpps_mode = 0;
|
|
pps_kc_hardpps_dev = NULL;
|
|
spin_unlock_irq(&pps_kc_hardpps_lock);
|
|
dev_info(pps->dev, "unbound kernel"
|
|
" consumer\n");
|
|
} else {
|
|
spin_unlock_irq(&pps_kc_hardpps_lock);
|
|
dev_err(pps->dev, "selected kernel consumer"
|
|
" is not bound\n");
|
|
return -EINVAL;
|
|
}
|
|
else
|
|
if (pps_kc_hardpps_dev == NULL ||
|
|
pps_kc_hardpps_dev == pps) {
|
|
pps_kc_hardpps_mode = bind_args->edge;
|
|
pps_kc_hardpps_dev = pps;
|
|
spin_unlock_irq(&pps_kc_hardpps_lock);
|
|
dev_info(pps->dev, "bound kernel consumer: "
|
|
"edge=0x%x\n", bind_args->edge);
|
|
} else {
|
|
spin_unlock_irq(&pps_kc_hardpps_lock);
|
|
dev_err(pps->dev, "another kernel consumer"
|
|
" is already bound\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* pps_kc_remove - unbind kernel consumer on PPS source removal
|
|
* @pps: the PPS source
|
|
*
|
|
* This function is used to disable kernel consumer on PPS source removal
|
|
* if this source was bound to PPS kernel consumer. Can be called on any
|
|
* source safely. Should not be called in interrupt context.
|
|
*/
|
|
void pps_kc_remove(struct pps_device *pps)
|
|
{
|
|
spin_lock_irq(&pps_kc_hardpps_lock);
|
|
if (pps == pps_kc_hardpps_dev) {
|
|
pps_kc_hardpps_mode = 0;
|
|
pps_kc_hardpps_dev = NULL;
|
|
spin_unlock_irq(&pps_kc_hardpps_lock);
|
|
dev_info(pps->dev, "unbound kernel consumer"
|
|
" on device removal\n");
|
|
} else
|
|
spin_unlock_irq(&pps_kc_hardpps_lock);
|
|
}
|
|
|
|
/* pps_kc_event - call hardpps() on PPS event
|
|
* @pps: the PPS source
|
|
* @ts: PPS event timestamp
|
|
* @event: PPS event edge
|
|
*
|
|
* This function calls hardpps() when an event from bound PPS source occurs.
|
|
*/
|
|
void pps_kc_event(struct pps_device *pps, struct pps_event_time *ts,
|
|
int event)
|
|
{
|
|
unsigned long flags;
|
|
|
|
/* Pass some events to kernel consumer if activated */
|
|
spin_lock_irqsave(&pps_kc_hardpps_lock, flags);
|
|
if (pps == pps_kc_hardpps_dev && event & pps_kc_hardpps_mode)
|
|
hardpps(&ts->ts_real, &ts->ts_raw);
|
|
spin_unlock_irqrestore(&pps_kc_hardpps_lock, flags);
|
|
}
|