Orange Pi5 kernel

// 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");