linux/drivers/pps/clients/pps-gpio.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

276 lines
7.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* pps-gpio.c -- PPS client driver using GPIO
*
* Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
* Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
*/
#define PPS_GPIO_NAME "pps-gpio"
#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/pps_kernel.h>
#include <linux/pps-gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/list.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
/* Info for each registered platform device */
struct pps_gpio_device_data {
int irq; /* IRQ used as PPS source */
struct pps_device *pps; /* PPS source device */
struct pps_source_info info; /* PPS source information */
struct gpio_desc *gpio_pin; /* GPIO port descriptors */
struct gpio_desc *echo_pin;
struct timer_list echo_timer; /* timer to reset echo active state */
bool assert_falling_edge;
bool capture_clear;
unsigned int echo_active_ms; /* PPS echo active duration */
unsigned long echo_timeout; /* timer timeout value in jiffies */
};
/*
* Report the PPS event
*/
static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
{
const struct pps_gpio_device_data *info;
struct pps_event_time ts;
int rising_edge;
/* Get the time stamp first */
pps_get_ts(&ts);
info = data;
rising_edge = gpiod_get_value(info->gpio_pin);
if ((rising_edge && !info->assert_falling_edge) ||
(!rising_edge && info->assert_falling_edge))
pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data);
else if (info->capture_clear &&
((rising_edge && info->assert_falling_edge) ||
(!rising_edge && !info->assert_falling_edge)))
pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data);
return IRQ_HANDLED;
}
/* This function will only be called when an ECHO GPIO is defined */
static void pps_gpio_echo(struct pps_device *pps, int event, void *data)
{
/* add_timer() needs to write into info->echo_timer */
struct pps_gpio_device_data *info = data;
switch (event) {
case PPS_CAPTUREASSERT:
if (pps->params.mode & PPS_ECHOASSERT)
gpiod_set_value(info->echo_pin, 1);
break;
case PPS_CAPTURECLEAR:
if (pps->params.mode & PPS_ECHOCLEAR)
gpiod_set_value(info->echo_pin, 1);
break;
}
/* fire the timer */
if (info->pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) {
info->echo_timer.expires = jiffies + info->echo_timeout;
add_timer(&info->echo_timer);
}
}
/* Timer callback to reset the echo pin to the inactive state */
static void pps_gpio_echo_timer_callback(struct timer_list *t)
{
const struct pps_gpio_device_data *info;
info = from_timer(info, t, echo_timer);
gpiod_set_value(info->echo_pin, 0);
}
static int pps_gpio_setup(struct platform_device *pdev)
{
struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
struct device_node *np = pdev->dev.of_node;
int ret;
u32 value;
data->gpio_pin = devm_gpiod_get(&pdev->dev,
NULL, /* request "gpios" */
GPIOD_IN);
if (IS_ERR(data->gpio_pin)) {
dev_err(&pdev->dev,
"failed to request PPS GPIO\n");
return PTR_ERR(data->gpio_pin);
}
data->echo_pin = devm_gpiod_get_optional(&pdev->dev,
"echo",
GPIOD_OUT_LOW);
if (data->echo_pin) {
if (IS_ERR(data->echo_pin)) {
dev_err(&pdev->dev, "failed to request ECHO GPIO\n");
return PTR_ERR(data->echo_pin);
}
ret = of_property_read_u32(np,
"echo-active-ms",
&value);
if (ret) {
dev_err(&pdev->dev,
"failed to get echo-active-ms from OF\n");
return ret;
}
data->echo_active_ms = value;
/* sanity check on echo_active_ms */
if (!data->echo_active_ms || data->echo_active_ms > 999) {
dev_err(&pdev->dev,
"echo-active-ms: %u - bad value from OF\n",
data->echo_active_ms);
return -EINVAL;
}
}
if (of_property_read_bool(np, "assert-falling-edge"))
data->assert_falling_edge = true;
return 0;
}
static unsigned long
get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
{
unsigned long flags = data->assert_falling_edge ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
if (data->capture_clear) {
flags |= ((flags & IRQF_TRIGGER_RISING) ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
}
return flags;
}
static int pps_gpio_probe(struct platform_device *pdev)
{
struct pps_gpio_device_data *data;
int ret;
int pps_default_params;
const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
/* allocate space for device info */
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
platform_set_drvdata(pdev, data);
/* GPIO setup */
if (pdata) {
data->gpio_pin = pdata->gpio_pin;
data->echo_pin = pdata->echo_pin;
data->assert_falling_edge = pdata->assert_falling_edge;
data->capture_clear = pdata->capture_clear;
data->echo_active_ms = pdata->echo_active_ms;
} else {
ret = pps_gpio_setup(pdev);
if (ret)
return -EINVAL;
}
/* IRQ setup */
ret = gpiod_to_irq(data->gpio_pin);
if (ret < 0) {
dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
return -EINVAL;
}
data->irq = ret;
/* initialize PPS specific parts of the bookkeeping data structure. */
data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
if (data->capture_clear)
data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
PPS_ECHOCLEAR;
data->info.owner = THIS_MODULE;
snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
pdev->name, pdev->id);
if (data->echo_pin) {
data->info.echo = pps_gpio_echo;
data->echo_timeout = msecs_to_jiffies(data->echo_active_ms);
timer_setup(&data->echo_timer, pps_gpio_echo_timer_callback, 0);
}
/* register PPS source */
pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
if (data->capture_clear)
pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
data->pps = pps_register_source(&data->info, pps_default_params);
if (IS_ERR(data->pps)) {
dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
data->irq);
return PTR_ERR(data->pps);
}
/* register IRQ interrupt handler */
ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
get_irqf_trigger_flags(data), data->info.name, data);
if (ret) {
pps_unregister_source(data->pps);
dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
return -EINVAL;
}
dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
data->irq);
return 0;
}
static int pps_gpio_remove(struct platform_device *pdev)
{
struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
pps_unregister_source(data->pps);
if (data->echo_pin) {
del_timer_sync(&data->echo_timer);
/* reset echo pin in any case */
gpiod_set_value(data->echo_pin, 0);
}
dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
return 0;
}
static const struct of_device_id pps_gpio_dt_ids[] = {
{ .compatible = "pps-gpio", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
static struct platform_driver pps_gpio_driver = {
.probe = pps_gpio_probe,
.remove = pps_gpio_remove,
.driver = {
.name = PPS_GPIO_NAME,
.of_match_table = pps_gpio_dt_ids,
},
};
module_platform_driver(pps_gpio_driver);
MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
MODULE_DESCRIPTION("Use GPIO pin as PPS source");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.2.0");