[mirror_ubuntu-jammy-kernel.git] / drivers / pps / clients / pps-gpio.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");
Commit	Line	Data
74ba9207	1	// SPDX-License-Identifier: GPL-2.0-or-later
16152045 JN	2	/*
	3	* pps-gpio.c -- PPS client driver using GPIO
	4	*
16152045 JN	5	* Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
16152045 JN	6	* Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
16152045 JN	7	*/
	8
	9	#define PPS_GPIO_NAME "pps-gpio"
	10	#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
	11
	12	#include <linux/init.h>
	13	#include <linux/kernel.h>
	14	#include <linux/interrupt.h>
	15	#include <linux/module.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/slab.h>
	18	#include <linux/pps_kernel.h>
	19	#include <linux/pps-gpio.h>
4461d651	20	#include <linux/gpio/consumer.h>
16152045	21	#include <linux/list.h>
c5dbcf8b JL	22	#include <linux/of_device.h>
c5dbcf8b JL	23	#include <linux/of_gpio.h>
4c69add4 TB	24	#include <linux/timer.h>
4c69add4 TB	25	#include <linux/jiffies.h>
16152045 JN	26
	27	/* Info for each registered platform device */
	28	struct pps_gpio_device_data {
	29	int irq; /* IRQ used as PPS source */
	30	struct pps_device pps; / PPS source device */
	31	struct pps_source_info info; /* PPS source information */
4461d651	32	struct gpio_desc gpio_pin; / GPIO port descriptors */
4c69add4 TB	33	struct gpio_desc *echo_pin;
4c69add4 TB	34	struct timer_list echo_timer; /* timer to reset echo active state */
c5dbcf8b JL	35	bool assert_falling_edge;
c5dbcf8b JL	36	bool capture_clear;
4c69add4 TB	37	unsigned int echo_active_ms; /* PPS echo active duration */
4c69add4 TB	38	unsigned long echo_timeout; /* timer timeout value in jiffies */
16152045 JN	39	};
	40
	41	/*
	42	* Report the PPS event
	43	*/
	44
	45	static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
	46	{
	47	const struct pps_gpio_device_data *info;
	48	struct pps_event_time ts;
	49	int rising_edge;
	50
	51	/* Get the time stamp first */
	52	pps_get_ts(&ts);
	53
	54	info = data;
	55
4461d651	56	rising_edge = gpiod_get_value(info->gpio_pin);
c5dbcf8b JL	57	if ((rising_edge && !info->assert_falling_edge) \|\|
c5dbcf8b JL	58	(!rising_edge && info->assert_falling_edge))
4c69add4	59	pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data);
c5dbcf8b JL	60	else if (info->capture_clear &&
c5dbcf8b JL	61	((rising_edge && info->assert_falling_edge) \|\|
4461d651	62	(!rising_edge && !info->assert_falling_edge)))
4c69add4	63	pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data);
16152045 JN	64
	65	return IRQ_HANDLED;
	66	}
	67
4c69add4 TB	68	/* This function will only be called when an ECHO GPIO is defined */
	69	static void pps_gpio_echo(struct pps_device pps, int event, void data)
	70	{
	71	/* add_timer() needs to write into info->echo_timer */
	72	struct pps_gpio_device_data *info = data;
	73
	74	switch (event) {
	75	case PPS_CAPTUREASSERT:
	76	if (pps->params.mode & PPS_ECHOASSERT)
	77	gpiod_set_value(info->echo_pin, 1);
	78	break;
	79
	80	case PPS_CAPTURECLEAR:
	81	if (pps->params.mode & PPS_ECHOCLEAR)
	82	gpiod_set_value(info->echo_pin, 1);
	83	break;
	84	}
	85
	86	/* fire the timer */
	87	if (info->pps->params.mode & (PPS_ECHOASSERT \| PPS_ECHOCLEAR)) {
	88	info->echo_timer.expires = jiffies + info->echo_timeout;
	89	add_timer(&info->echo_timer);
	90	}
	91	}
	92
	93	/* Timer callback to reset the echo pin to the inactive state */
	94	static void pps_gpio_echo_timer_callback(struct timer_list *t)
	95	{
	96	const struct pps_gpio_device_data *info;
	97
	98	info = from_timer(info, t, echo_timer);
	99
	100	gpiod_set_value(info->echo_pin, 0);
	101	}
	102
4461d651 TB	103	static int pps_gpio_setup(struct platform_device *pdev)
	104	{
	105	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
	106	struct device_node *np = pdev->dev.of_node;
4c69add4 TB	107	int ret;
4c69add4 TB	108	u32 value;
4461d651 TB	109
	110	data->gpio_pin = devm_gpiod_get(&pdev->dev,
	111	NULL, /* request "gpios" */
	112	GPIOD_IN);
	113	if (IS_ERR(data->gpio_pin)) {
	114	dev_err(&pdev->dev,
	115	"failed to request PPS GPIO\n");
	116	return PTR_ERR(data->gpio_pin);
	117	}
	118
4c69add4 TB	119	data->echo_pin = devm_gpiod_get_optional(&pdev->dev,
	120	"echo",
	121	GPIOD_OUT_LOW);
	122	if (data->echo_pin) {
	123	if (IS_ERR(data->echo_pin)) {
	124	dev_err(&pdev->dev, "failed to request ECHO GPIO\n");
	125	return PTR_ERR(data->echo_pin);
	126	}
	127
	128	ret = of_property_read_u32(np,
	129	"echo-active-ms",
	130	&value);
	131	if (ret) {
	132	dev_err(&pdev->dev,
	133	"failed to get echo-active-ms from OF\n");
	134	return ret;
	135	}
	136	data->echo_active_ms = value;
	137	/* sanity check on echo_active_ms */
	138	if (!data->echo_active_ms \|\| data->echo_active_ms > 999) {
	139	dev_err(&pdev->dev,
	140	"echo-active-ms: %u - bad value from OF\n",
	141	data->echo_active_ms);
	142	return -EINVAL;
	143	}
	144	}
	145
4461d651 TB	146	if (of_property_read_bool(np, "assert-falling-edge"))
	147	data->assert_falling_edge = true;
	148	return 0;
	149	}
	150
16152045	151	static unsigned long
c5dbcf8b	152	get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
16152045	153	{
c5dbcf8b	154	unsigned long flags = data->assert_falling_edge ?
16152045 JN	155	IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
16152045 JN	156
c5dbcf8b	157	if (data->capture_clear) {
16152045 JN	158	flags \|= ((flags & IRQF_TRIGGER_RISING) ?
	159	IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
	160	}
	161
	162	return flags;
	163	}
	164
	165	static int pps_gpio_probe(struct platform_device *pdev)
	166	{
	167	struct pps_gpio_device_data *data;
16152045	168	int ret;
16152045 JN	169	int pps_default_params;
16152045 JN	170	const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
c5dbcf8b JL	171
c5dbcf8b JL	172	/* allocate space for device info */
4461d651	173	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
c5dbcf8b JL	174	if (!data)
c5dbcf8b JL	175	return -ENOMEM;
4461d651	176	platform_set_drvdata(pdev, data);
16152045	177
4461d651	178	/* GPIO setup */
c5dbcf8b JL	179	if (pdata) {
c5dbcf8b JL	180	data->gpio_pin = pdata->gpio_pin;
4c69add4	181	data->echo_pin = pdata->echo_pin;
c5dbcf8b JL	182
	183	data->assert_falling_edge = pdata->assert_falling_edge;
	184	data->capture_clear = pdata->capture_clear;
4c69add4	185	data->echo_active_ms = pdata->echo_active_ms;
c5dbcf8b	186	} else {
4461d651 TB	187	ret = pps_gpio_setup(pdev);
	188	if (ret)
	189	return -EINVAL;
c5dbcf8b	190	}
16152045 JN	191
16152045 JN	192	/* IRQ setup */
4461d651	193	ret = gpiod_to_irq(data->gpio_pin);
c5dbcf8b JL	194	if (ret < 0) {
c5dbcf8b JL	195	dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
2a651822	196	return -EINVAL;
16152045	197	}
c5dbcf8b	198	data->irq = ret;
16152045 JN	199
	200	/* initialize PPS specific parts of the bookkeeping data structure. */
	201	data->info.mode = PPS_CAPTUREASSERT \| PPS_OFFSETASSERT \|
	202	PPS_ECHOASSERT \| PPS_CANWAIT \| PPS_TSFMT_TSPEC;
c5dbcf8b	203	if (data->capture_clear)
16152045 JN	204	data->info.mode \|= PPS_CAPTURECLEAR \| PPS_OFFSETCLEAR \|
	205	PPS_ECHOCLEAR;
	206	data->info.owner = THIS_MODULE;
	207	snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
	208	pdev->name, pdev->id);
4c69add4 TB	209	if (data->echo_pin) {
	210	data->info.echo = pps_gpio_echo;
	211	data->echo_timeout = msecs_to_jiffies(data->echo_active_ms);
	212	timer_setup(&data->echo_timer, pps_gpio_echo_timer_callback, 0);
	213	}
16152045 JN	214
	215	/* register PPS source */
	216	pps_default_params = PPS_CAPTUREASSERT \| PPS_OFFSETASSERT;
c5dbcf8b	217	if (data->capture_clear)
16152045 JN	218	pps_default_params \|= PPS_CAPTURECLEAR \| PPS_OFFSETCLEAR;
16152045 JN	219	data->pps = pps_register_source(&data->info, pps_default_params);
3b1ad360	220	if (IS_ERR(data->pps)) {
c5dbcf8b JL	221	dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
c5dbcf8b JL	222	data->irq);
3b1ad360	223	return PTR_ERR(data->pps);
16152045 JN	224	}
16152045 JN	225
16152045	226	/* register IRQ interrupt handler */
c5dbcf8b JL	227	ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
c5dbcf8b JL	228	get_irqf_trigger_flags(data), data->info.name, data);
16152045 JN	229	if (ret) {
16152045 JN	230	pps_unregister_source(data->pps);
c5dbcf8b	231	dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
2a651822	232	return -EINVAL;
16152045 JN	233	}
16152045 JN	234
c5dbcf8b JL	235	dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
c5dbcf8b JL	236	data->irq);
16152045 JN	237
16152045 JN	238	return 0;
16152045 JN	239	}
	240
	241	static int pps_gpio_remove(struct platform_device *pdev)
	242	{
	243	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
16152045	244
16152045	245	pps_unregister_source(data->pps);
4c69add4 TB	246	if (data->echo_pin) {
	247	del_timer_sync(&data->echo_timer);
	248	/* reset echo pin in any case */
	249	gpiod_set_value(data->echo_pin, 0);
	250	}
c5dbcf8b	251	dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
16152045 JN	252	return 0;
	253	}
	254
c5dbcf8b JL	255	static const struct of_device_id pps_gpio_dt_ids[] = {
	256	{ .compatible = "pps-gpio", },
	257	{ /* sentinel */ }
	258	};
	259	MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
	260
16152045 JN	261	static struct platform_driver pps_gpio_driver = {
16152045 JN	262	.probe = pps_gpio_probe,
0fe763c5	263	.remove = pps_gpio_remove,
16152045 JN	264	.driver = {
16152045 JN	265	.name = PPS_GPIO_NAME,
1a10bd94	266	.of_match_table = pps_gpio_dt_ids,
16152045 JN	267	},
	268	};
	269
05212be3	270	module_platform_driver(pps_gpio_driver);
16152045 JN	271	MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
	272	MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
	273	MODULE_DESCRIPTION("Use GPIO pin as PPS source");
	274	MODULE_LICENSE("GPL");
4c69add4	275	MODULE_VERSION("1.2.0");