mirror of https://gitee.com/openkylin/linux.git
290 lines
8.0 KiB
C
290 lines
8.0 KiB
C
/*
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* pps-gpio.c -- PPS client driver using GPIO
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*
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*
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* Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
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* Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#define PPS_GPIO_NAME "pps-gpio"
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#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/pps_kernel.h>
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#include <linux/pps-gpio.h>
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#include <linux/gpio/consumer.h>
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#include <linux/list.h>
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#include <linux/of_device.h>
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#include <linux/of_gpio.h>
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#include <linux/timer.h>
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#include <linux/jiffies.h>
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/* Info for each registered platform device */
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struct pps_gpio_device_data {
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int irq; /* IRQ used as PPS source */
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struct pps_device *pps; /* PPS source device */
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struct pps_source_info info; /* PPS source information */
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struct gpio_desc *gpio_pin; /* GPIO port descriptors */
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struct gpio_desc *echo_pin;
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struct timer_list echo_timer; /* timer to reset echo active state */
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bool assert_falling_edge;
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bool capture_clear;
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unsigned int echo_active_ms; /* PPS echo active duration */
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unsigned long echo_timeout; /* timer timeout value in jiffies */
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};
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/*
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* Report the PPS event
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*/
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static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
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{
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const struct pps_gpio_device_data *info;
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struct pps_event_time ts;
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int rising_edge;
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/* Get the time stamp first */
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pps_get_ts(&ts);
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info = data;
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rising_edge = gpiod_get_value(info->gpio_pin);
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if ((rising_edge && !info->assert_falling_edge) ||
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(!rising_edge && info->assert_falling_edge))
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pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data);
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else if (info->capture_clear &&
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((rising_edge && info->assert_falling_edge) ||
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(!rising_edge && !info->assert_falling_edge)))
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pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data);
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return IRQ_HANDLED;
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}
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/* This function will only be called when an ECHO GPIO is defined */
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static void pps_gpio_echo(struct pps_device *pps, int event, void *data)
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{
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/* add_timer() needs to write into info->echo_timer */
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struct pps_gpio_device_data *info = data;
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switch (event) {
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case PPS_CAPTUREASSERT:
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if (pps->params.mode & PPS_ECHOASSERT)
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gpiod_set_value(info->echo_pin, 1);
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break;
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case PPS_CAPTURECLEAR:
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if (pps->params.mode & PPS_ECHOCLEAR)
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gpiod_set_value(info->echo_pin, 1);
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break;
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}
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/* fire the timer */
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if (info->pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) {
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info->echo_timer.expires = jiffies + info->echo_timeout;
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add_timer(&info->echo_timer);
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}
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}
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/* Timer callback to reset the echo pin to the inactive state */
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static void pps_gpio_echo_timer_callback(struct timer_list *t)
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{
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const struct pps_gpio_device_data *info;
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info = from_timer(info, t, echo_timer);
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gpiod_set_value(info->echo_pin, 0);
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}
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static int pps_gpio_setup(struct platform_device *pdev)
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{
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struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
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struct device_node *np = pdev->dev.of_node;
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int ret;
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u32 value;
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data->gpio_pin = devm_gpiod_get(&pdev->dev,
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NULL, /* request "gpios" */
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GPIOD_IN);
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if (IS_ERR(data->gpio_pin)) {
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dev_err(&pdev->dev,
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"failed to request PPS GPIO\n");
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return PTR_ERR(data->gpio_pin);
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}
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data->echo_pin = devm_gpiod_get_optional(&pdev->dev,
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"echo",
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GPIOD_OUT_LOW);
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if (data->echo_pin) {
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if (IS_ERR(data->echo_pin)) {
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dev_err(&pdev->dev, "failed to request ECHO GPIO\n");
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return PTR_ERR(data->echo_pin);
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}
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ret = of_property_read_u32(np,
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"echo-active-ms",
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&value);
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if (ret) {
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dev_err(&pdev->dev,
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"failed to get echo-active-ms from OF\n");
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return ret;
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}
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data->echo_active_ms = value;
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/* sanity check on echo_active_ms */
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if (!data->echo_active_ms || data->echo_active_ms > 999) {
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dev_err(&pdev->dev,
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"echo-active-ms: %u - bad value from OF\n",
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data->echo_active_ms);
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return -EINVAL;
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}
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}
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if (of_property_read_bool(np, "assert-falling-edge"))
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data->assert_falling_edge = true;
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return 0;
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}
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static unsigned long
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get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
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{
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unsigned long flags = data->assert_falling_edge ?
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IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
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if (data->capture_clear) {
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flags |= ((flags & IRQF_TRIGGER_RISING) ?
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IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
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}
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return flags;
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}
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static int pps_gpio_probe(struct platform_device *pdev)
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{
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struct pps_gpio_device_data *data;
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int ret;
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int pps_default_params;
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const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
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/* allocate space for device info */
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data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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platform_set_drvdata(pdev, data);
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/* GPIO setup */
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if (pdata) {
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data->gpio_pin = pdata->gpio_pin;
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data->echo_pin = pdata->echo_pin;
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data->assert_falling_edge = pdata->assert_falling_edge;
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data->capture_clear = pdata->capture_clear;
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data->echo_active_ms = pdata->echo_active_ms;
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} else {
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ret = pps_gpio_setup(pdev);
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if (ret)
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return -EINVAL;
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}
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/* IRQ setup */
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ret = gpiod_to_irq(data->gpio_pin);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
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return -EINVAL;
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}
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data->irq = ret;
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/* initialize PPS specific parts of the bookkeeping data structure. */
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data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
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PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
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if (data->capture_clear)
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data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
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PPS_ECHOCLEAR;
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data->info.owner = THIS_MODULE;
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snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
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pdev->name, pdev->id);
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if (data->echo_pin) {
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data->info.echo = pps_gpio_echo;
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data->echo_timeout = msecs_to_jiffies(data->echo_active_ms);
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timer_setup(&data->echo_timer, pps_gpio_echo_timer_callback, 0);
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}
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/* register PPS source */
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pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
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if (data->capture_clear)
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pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
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data->pps = pps_register_source(&data->info, pps_default_params);
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if (IS_ERR(data->pps)) {
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dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
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data->irq);
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return PTR_ERR(data->pps);
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}
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/* register IRQ interrupt handler */
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ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
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get_irqf_trigger_flags(data), data->info.name, data);
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if (ret) {
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pps_unregister_source(data->pps);
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dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
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return -EINVAL;
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}
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dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
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data->irq);
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return 0;
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}
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static int pps_gpio_remove(struct platform_device *pdev)
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{
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struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
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pps_unregister_source(data->pps);
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if (data->echo_pin) {
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del_timer_sync(&data->echo_timer);
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/* reset echo pin in any case */
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gpiod_set_value(data->echo_pin, 0);
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}
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dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
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return 0;
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}
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static const struct of_device_id pps_gpio_dt_ids[] = {
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{ .compatible = "pps-gpio", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
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static struct platform_driver pps_gpio_driver = {
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.probe = pps_gpio_probe,
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.remove = pps_gpio_remove,
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.driver = {
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.name = PPS_GPIO_NAME,
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.of_match_table = pps_gpio_dt_ids,
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},
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};
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module_platform_driver(pps_gpio_driver);
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MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
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MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
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MODULE_DESCRIPTION("Use GPIO pin as PPS source");
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MODULE_LICENSE("GPL");
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MODULE_VERSION("1.2.0");
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