174ba9207SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 216152045SJames Nuss /* 316152045SJames Nuss * pps-gpio.c -- PPS client driver using GPIO 416152045SJames Nuss * 516152045SJames Nuss * Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt> 616152045SJames Nuss * Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca> 716152045SJames Nuss */ 816152045SJames Nuss 916152045SJames Nuss #define PPS_GPIO_NAME "pps-gpio" 1016152045SJames Nuss #define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt 1116152045SJames Nuss 1216152045SJames Nuss #include <linux/init.h> 1316152045SJames Nuss #include <linux/kernel.h> 1416152045SJames Nuss #include <linux/interrupt.h> 15*28d03251SAndy Shevchenko #include <linux/mod_devicetable.h> 1616152045SJames Nuss #include <linux/module.h> 1716152045SJames Nuss #include <linux/platform_device.h> 1816152045SJames Nuss #include <linux/slab.h> 1916152045SJames Nuss #include <linux/pps_kernel.h> 204461d651STom Burkart #include <linux/gpio/consumer.h> 2116152045SJames Nuss #include <linux/list.h> 22*28d03251SAndy Shevchenko #include <linux/property.h> 234c69add4STom Burkart #include <linux/timer.h> 244c69add4STom Burkart #include <linux/jiffies.h> 2516152045SJames Nuss 2616152045SJames Nuss /* Info for each registered platform device */ 2716152045SJames Nuss struct pps_gpio_device_data { 2816152045SJames Nuss int irq; /* IRQ used as PPS source */ 2916152045SJames Nuss struct pps_device *pps; /* PPS source device */ 3016152045SJames Nuss struct pps_source_info info; /* PPS source information */ 314461d651STom Burkart struct gpio_desc *gpio_pin; /* GPIO port descriptors */ 324c69add4STom Burkart struct gpio_desc *echo_pin; 334c69add4STom Burkart struct timer_list echo_timer; /* timer to reset echo active state */ 34c5dbcf8bSJan Luebbe bool assert_falling_edge; 35c5dbcf8bSJan Luebbe bool capture_clear; 364c69add4STom Burkart unsigned int echo_active_ms; /* PPS echo active duration */ 374c69add4STom Burkart unsigned long echo_timeout; /* timer timeout value in jiffies */ 3816152045SJames Nuss }; 3916152045SJames Nuss 4016152045SJames Nuss /* 4116152045SJames Nuss * Report the PPS event 4216152045SJames Nuss */ 4316152045SJames Nuss 4416152045SJames Nuss static irqreturn_t pps_gpio_irq_handler(int irq, void *data) 4516152045SJames Nuss { 4616152045SJames Nuss const struct pps_gpio_device_data *info; 4716152045SJames Nuss struct pps_event_time ts; 4816152045SJames Nuss int rising_edge; 4916152045SJames Nuss 5016152045SJames Nuss /* Get the time stamp first */ 5116152045SJames Nuss pps_get_ts(&ts); 5216152045SJames Nuss 5316152045SJames Nuss info = data; 5416152045SJames Nuss 554461d651STom Burkart rising_edge = gpiod_get_value(info->gpio_pin); 56c5dbcf8bSJan Luebbe if ((rising_edge && !info->assert_falling_edge) || 57c5dbcf8bSJan Luebbe (!rising_edge && info->assert_falling_edge)) 584c69add4STom Burkart pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data); 59c5dbcf8bSJan Luebbe else if (info->capture_clear && 60c5dbcf8bSJan Luebbe ((rising_edge && info->assert_falling_edge) || 61c5dbcf8bSJan Luebbe (!rising_edge && !info->assert_falling_edge))) 624c69add4STom Burkart pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data); 6316152045SJames Nuss 6416152045SJames Nuss return IRQ_HANDLED; 6516152045SJames Nuss } 6616152045SJames Nuss 674c69add4STom Burkart /* This function will only be called when an ECHO GPIO is defined */ 684c69add4STom Burkart static void pps_gpio_echo(struct pps_device *pps, int event, void *data) 694c69add4STom Burkart { 704c69add4STom Burkart /* add_timer() needs to write into info->echo_timer */ 714c69add4STom Burkart struct pps_gpio_device_data *info = data; 724c69add4STom Burkart 734c69add4STom Burkart switch (event) { 744c69add4STom Burkart case PPS_CAPTUREASSERT: 754c69add4STom Burkart if (pps->params.mode & PPS_ECHOASSERT) 764c69add4STom Burkart gpiod_set_value(info->echo_pin, 1); 774c69add4STom Burkart break; 784c69add4STom Burkart 794c69add4STom Burkart case PPS_CAPTURECLEAR: 804c69add4STom Burkart if (pps->params.mode & PPS_ECHOCLEAR) 814c69add4STom Burkart gpiod_set_value(info->echo_pin, 1); 824c69add4STom Burkart break; 834c69add4STom Burkart } 844c69add4STom Burkart 854c69add4STom Burkart /* fire the timer */ 864c69add4STom Burkart if (info->pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) { 874c69add4STom Burkart info->echo_timer.expires = jiffies + info->echo_timeout; 884c69add4STom Burkart add_timer(&info->echo_timer); 894c69add4STom Burkart } 904c69add4STom Burkart } 914c69add4STom Burkart 924c69add4STom Burkart /* Timer callback to reset the echo pin to the inactive state */ 934c69add4STom Burkart static void pps_gpio_echo_timer_callback(struct timer_list *t) 944c69add4STom Burkart { 954c69add4STom Burkart const struct pps_gpio_device_data *info; 964c69add4STom Burkart 974c69add4STom Burkart info = from_timer(info, t, echo_timer); 984c69add4STom Burkart 994c69add4STom Burkart gpiod_set_value(info->echo_pin, 0); 1004c69add4STom Burkart } 1014c69add4STom Burkart 1024461d651STom Burkart static int pps_gpio_setup(struct platform_device *pdev) 1034461d651STom Burkart { 1044461d651STom Burkart struct pps_gpio_device_data *data = platform_get_drvdata(pdev); 1054c69add4STom Burkart int ret; 1064c69add4STom Burkart u32 value; 1074461d651STom Burkart 1084461d651STom Burkart data->gpio_pin = devm_gpiod_get(&pdev->dev, 1094461d651STom Burkart NULL, /* request "gpios" */ 1104461d651STom Burkart GPIOD_IN); 1111a8fc4f7SAndy Shevchenko if (IS_ERR(data->gpio_pin)) 1121a8fc4f7SAndy Shevchenko return dev_err_probe(&pdev->dev, PTR_ERR(data->gpio_pin), 1134461d651STom Burkart "failed to request PPS GPIO\n"); 1144461d651STom Burkart 1154c69add4STom Burkart data->echo_pin = devm_gpiod_get_optional(&pdev->dev, 1164c69add4STom Burkart "echo", 1174c69add4STom Burkart GPIOD_OUT_LOW); 1181a8fc4f7SAndy Shevchenko if (IS_ERR(data->echo_pin)) 1191a8fc4f7SAndy Shevchenko return dev_err_probe(&pdev->dev, PTR_ERR(data->echo_pin), 1201a8fc4f7SAndy Shevchenko "failed to request ECHO GPIO\n"); 1214c69add4STom Burkart 122a4780db3SAndy Shevchenko if (data->echo_pin) { 123*28d03251SAndy Shevchenko ret = device_property_read_u32(&pdev->dev, "echo-active-ms", &value); 1244c69add4STom Burkart if (ret) { 1254c69add4STom Burkart dev_err(&pdev->dev, 126*28d03251SAndy Shevchenko "failed to get echo-active-ms from FW\n"); 1274c69add4STom Burkart return ret; 1284c69add4STom Burkart } 1294c69add4STom Burkart data->echo_active_ms = value; 1304c69add4STom Burkart /* sanity check on echo_active_ms */ 1314c69add4STom Burkart if (!data->echo_active_ms || data->echo_active_ms > 999) { 1324c69add4STom Burkart dev_err(&pdev->dev, 133*28d03251SAndy Shevchenko "echo-active-ms: %u - bad value from FW\n", 1344c69add4STom Burkart data->echo_active_ms); 1354c69add4STom Burkart return -EINVAL; 1364c69add4STom Burkart } 1374c69add4STom Burkart } 1384c69add4STom Burkart 139*28d03251SAndy Shevchenko data->assert_falling_edge = 140*28d03251SAndy Shevchenko device_property_read_bool(&pdev->dev, "assert-falling-edge"); 1414461d651STom Burkart return 0; 1424461d651STom Burkart } 1434461d651STom Burkart 14416152045SJames Nuss static unsigned long 145c5dbcf8bSJan Luebbe get_irqf_trigger_flags(const struct pps_gpio_device_data *data) 14616152045SJames Nuss { 147c5dbcf8bSJan Luebbe unsigned long flags = data->assert_falling_edge ? 14816152045SJames Nuss IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 14916152045SJames Nuss 150c5dbcf8bSJan Luebbe if (data->capture_clear) { 15116152045SJames Nuss flags |= ((flags & IRQF_TRIGGER_RISING) ? 15216152045SJames Nuss IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING); 15316152045SJames Nuss } 15416152045SJames Nuss 15516152045SJames Nuss return flags; 15616152045SJames Nuss } 15716152045SJames Nuss 15816152045SJames Nuss static int pps_gpio_probe(struct platform_device *pdev) 15916152045SJames Nuss { 16016152045SJames Nuss struct pps_gpio_device_data *data; 16116152045SJames Nuss int ret; 16216152045SJames Nuss int pps_default_params; 16316152045SJames Nuss 16416152045SJames Nuss /* allocate space for device info */ 1654461d651STom Burkart data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 166c5dbcf8bSJan Luebbe if (!data) 1672a651822SJan Luebbe return -ENOMEM; 1684461d651STom Burkart platform_set_drvdata(pdev, data); 16916152045SJames Nuss 1704461d651STom Burkart /* GPIO setup */ 1714461d651STom Burkart ret = pps_gpio_setup(pdev); 1724461d651STom Burkart if (ret) 173c5dbcf8bSJan Luebbe return -EINVAL; 174c5dbcf8bSJan Luebbe 175c5dbcf8bSJan Luebbe /* IRQ setup */ 1764461d651STom Burkart ret = gpiod_to_irq(data->gpio_pin); 177c5dbcf8bSJan Luebbe if (ret < 0) { 178c5dbcf8bSJan Luebbe dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret); 179c5dbcf8bSJan Luebbe return -EINVAL; 180c5dbcf8bSJan Luebbe } 181c5dbcf8bSJan Luebbe data->irq = ret; 182c5dbcf8bSJan Luebbe 18316152045SJames Nuss /* initialize PPS specific parts of the bookkeeping data structure. */ 18416152045SJames Nuss data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT | 18516152045SJames Nuss PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC; 186c5dbcf8bSJan Luebbe if (data->capture_clear) 18716152045SJames Nuss data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR | 18816152045SJames Nuss PPS_ECHOCLEAR; 18916152045SJames Nuss data->info.owner = THIS_MODULE; 19016152045SJames Nuss snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d", 19116152045SJames Nuss pdev->name, pdev->id); 1924c69add4STom Burkart if (data->echo_pin) { 1934c69add4STom Burkart data->info.echo = pps_gpio_echo; 1944c69add4STom Burkart data->echo_timeout = msecs_to_jiffies(data->echo_active_ms); 1954c69add4STom Burkart timer_setup(&data->echo_timer, pps_gpio_echo_timer_callback, 0); 1964c69add4STom Burkart } 19716152045SJames Nuss 19816152045SJames Nuss /* register PPS source */ 19916152045SJames Nuss pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT; 200c5dbcf8bSJan Luebbe if (data->capture_clear) 20116152045SJames Nuss pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR; 20216152045SJames Nuss data->pps = pps_register_source(&data->info, pps_default_params); 2033b1ad360SYueHaibing if (IS_ERR(data->pps)) { 204c5dbcf8bSJan Luebbe dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n", 205c5dbcf8bSJan Luebbe data->irq); 2063b1ad360SYueHaibing return PTR_ERR(data->pps); 20716152045SJames Nuss } 20816152045SJames Nuss 20916152045SJames Nuss /* register IRQ interrupt handler */ 210c5dbcf8bSJan Luebbe ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler, 211c5dbcf8bSJan Luebbe get_irqf_trigger_flags(data), data->info.name, data); 21216152045SJames Nuss if (ret) { 21316152045SJames Nuss pps_unregister_source(data->pps); 214c5dbcf8bSJan Luebbe dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq); 2152a651822SJan Luebbe return -EINVAL; 21616152045SJames Nuss } 21716152045SJames Nuss 218c5dbcf8bSJan Luebbe dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n", 219c5dbcf8bSJan Luebbe data->irq); 22016152045SJames Nuss 22116152045SJames Nuss return 0; 22216152045SJames Nuss } 22316152045SJames Nuss 22416152045SJames Nuss static int pps_gpio_remove(struct platform_device *pdev) 22516152045SJames Nuss { 22616152045SJames Nuss struct pps_gpio_device_data *data = platform_get_drvdata(pdev); 22716152045SJames Nuss 22816152045SJames Nuss pps_unregister_source(data->pps); 2294c69add4STom Burkart del_timer_sync(&data->echo_timer); 2304c69add4STom Burkart /* reset echo pin in any case */ 2314c69add4STom Burkart gpiod_set_value(data->echo_pin, 0); 232c5dbcf8bSJan Luebbe dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq); 23316152045SJames Nuss return 0; 23416152045SJames Nuss } 23516152045SJames Nuss 236c5dbcf8bSJan Luebbe static const struct of_device_id pps_gpio_dt_ids[] = { 237c5dbcf8bSJan Luebbe { .compatible = "pps-gpio", }, 238c5dbcf8bSJan Luebbe { /* sentinel */ } 239c5dbcf8bSJan Luebbe }; 240c5dbcf8bSJan Luebbe MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids); 241c5dbcf8bSJan Luebbe 24216152045SJames Nuss static struct platform_driver pps_gpio_driver = { 24316152045SJames Nuss .probe = pps_gpio_probe, 2440fe763c5SGreg Kroah-Hartman .remove = pps_gpio_remove, 24516152045SJames Nuss .driver = { 24616152045SJames Nuss .name = PPS_GPIO_NAME, 2471a10bd94SSachin Kamat .of_match_table = pps_gpio_dt_ids, 24816152045SJames Nuss }, 24916152045SJames Nuss }; 25016152045SJames Nuss 25105212be3SJan Luebbe module_platform_driver(pps_gpio_driver); 25216152045SJames Nuss MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>"); 25316152045SJames Nuss MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>"); 25416152045SJames Nuss MODULE_DESCRIPTION("Use GPIO pin as PPS source"); 25516152045SJames Nuss MODULE_LICENSE("GPL"); 2564c69add4STom Burkart MODULE_VERSION("1.2.0"); 257