linux/drivers/pps/kc.c
Thomas Gleixner 74ba9207e1 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 441 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520071858.739733335@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:36:45 +02:00

110 lines
3.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* PPS kernel consumer API
*
* Copyright (C) 2009-2010 Alexander Gordeev <lasaine@lvk.cs.msu.su>
*/
#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);
}