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/*
* 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 */
static DEFINE_SPINLOCK(pps_kc_hardpps_lock);
/* PPS API (RFC 2783): current source and mode for kernel consumer */
static struct pps_device *pps_kc_hardpps_dev; /* unique pointer to device */
static 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);
}
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