[deliverable/linux.git] / drivers / pps / clients / pps-gpio.c

/*
 * 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>
 *
 *   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.
 */

#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.h>
#include <linux/list.h>
#include <linux/of_device.h>
#include <linux/of_gpio.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 */
	bool assert_falling_edge;
	bool capture_clear;
	unsigned int gpio_pin;
};

/*
 * 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 = gpio_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, NULL);
	else if (info->capture_clear &&
			((rising_edge && info->assert_falling_edge) ||
			 (!rising_edge && !info->assert_falling_edge)))
		pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);

	return IRQ_HANDLED;
}

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;
	const char *gpio_label;
	int ret;
	int pps_default_params;
	const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
	struct device_node *np = pdev->dev.of_node;

	/* allocate space for device info */
	data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),
			GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	if (pdata) {
		data->gpio_pin = pdata->gpio_pin;
		gpio_label = pdata->gpio_label;

		data->assert_falling_edge = pdata->assert_falling_edge;
		data->capture_clear = pdata->capture_clear;
	} else {
		ret = of_get_gpio(np, 0);
		if (ret < 0) {
			dev_err(&pdev->dev, "failed to get GPIO from device tree\n");
			return ret;
		}
		data->gpio_pin = ret;
		gpio_label = PPS_GPIO_NAME;

		if (of_get_property(np, "assert-falling-edge", NULL))
			data->assert_falling_edge = true;
	}

	/* GPIO setup */
	ret = devm_gpio_request(&pdev->dev, data->gpio_pin, gpio_label);
	if (ret) {
		dev_err(&pdev->dev, "failed to request GPIO %u\n",
			data->gpio_pin);
		return ret;
	}

	ret = gpio_direction_input(data->gpio_pin);
	if (ret) {
		dev_err(&pdev->dev, "failed to set pin direction\n");
		return -EINVAL;
	}

	/* IRQ setup */
	ret = gpio_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);

	/* 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 (data->pps == NULL) {
		dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
			data->irq);
		return -EINVAL;
	}

	/* 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;
	}

	platform_set_drvdata(pdev, data);
	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);
	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("1.0.0");
Commit	Line	Data
16152045 JN	1	/*
	2	* pps-gpio.c -- PPS client driver using GPIO
	3	*
	4	*
	5	* Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
	6	* Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to the Free Software
	20	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	21	*/
	22
	23	#define PPS_GPIO_NAME "pps-gpio"
	24	#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
	25
	26	#include <linux/init.h>
	27	#include <linux/kernel.h>
	28	#include <linux/interrupt.h>
	29	#include <linux/module.h>
	30	#include <linux/platform_device.h>
	31	#include <linux/slab.h>
	32	#include <linux/pps_kernel.h>
	33	#include <linux/pps-gpio.h>
	34	#include <linux/gpio.h>
	35	#include <linux/list.h>
c5dbcf8b JL	36	#include <linux/of_device.h>
c5dbcf8b JL	37	#include <linux/of_gpio.h>
16152045 JN	38
	39	/* Info for each registered platform device */
	40	struct pps_gpio_device_data {
	41	int irq; /* IRQ used as PPS source */
	42	struct pps_device pps; / PPS source device */
	43	struct pps_source_info info; /* PPS source information */
c5dbcf8b JL	44	bool assert_falling_edge;
	45	bool capture_clear;
	46	unsigned int gpio_pin;
16152045 JN	47	};
	48
	49	/*
	50	* Report the PPS event
	51	*/
	52
	53	static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
	54	{
	55	const struct pps_gpio_device_data *info;
	56	struct pps_event_time ts;
	57	int rising_edge;
	58
	59	/* Get the time stamp first */
	60	pps_get_ts(&ts);
	61
	62	info = data;
	63
c5dbcf8b JL	64	rising_edge = gpio_get_value(info->gpio_pin);
	65	if ((rising_edge && !info->assert_falling_edge) \|\|
	66	(!rising_edge && info->assert_falling_edge))
16152045	67	pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
c5dbcf8b JL	68	else if (info->capture_clear &&
	69	((rising_edge && info->assert_falling_edge) \|\|
	70	(!rising_edge && !info->assert_falling_edge)))
16152045 JN	71	pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
	72
	73	return IRQ_HANDLED;
	74	}
	75
16152045	76	static unsigned long
c5dbcf8b	77	get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
16152045	78	{
c5dbcf8b	79	unsigned long flags = data->assert_falling_edge ?
16152045 JN	80	IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
16152045 JN	81
c5dbcf8b	82	if (data->capture_clear) {
16152045 JN	83	flags \|= ((flags & IRQF_TRIGGER_RISING) ?
	84	IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
	85	}
	86
	87	return flags;
	88	}
	89
	90	static int pps_gpio_probe(struct platform_device *pdev)
	91	{
	92	struct pps_gpio_device_data *data;
c5dbcf8b	93	const char *gpio_label;
16152045	94	int ret;
16152045 JN	95	int pps_default_params;
16152045 JN	96	const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
c5dbcf8b JL	97	struct device_node *np = pdev->dev.of_node;
	98
	99	/* allocate space for device info */
	100	data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),
	101	GFP_KERNEL);
	102	if (!data)
	103	return -ENOMEM;
16152045	104
c5dbcf8b JL	105	if (pdata) {
	106	data->gpio_pin = pdata->gpio_pin;
	107	gpio_label = pdata->gpio_label;
	108
	109	data->assert_falling_edge = pdata->assert_falling_edge;
	110	data->capture_clear = pdata->capture_clear;
	111	} else {
	112	ret = of_get_gpio(np, 0);
	113	if (ret < 0) {
	114	dev_err(&pdev->dev, "failed to get GPIO from device tree\n");
	115	return ret;
	116	}
	117	data->gpio_pin = ret;
	118	gpio_label = PPS_GPIO_NAME;
	119
	120	if (of_get_property(np, "assert-falling-edge", NULL))
	121	data->assert_falling_edge = true;
	122	}
16152045 JN	123
16152045 JN	124	/* GPIO setup */
c5dbcf8b JL	125	ret = devm_gpio_request(&pdev->dev, data->gpio_pin, gpio_label);
	126	if (ret) {
	127	dev_err(&pdev->dev, "failed to request GPIO %u\n",
	128	data->gpio_pin);
	129	return ret;
	130	}
	131
	132	ret = gpio_direction_input(data->gpio_pin);
	133	if (ret) {
	134	dev_err(&pdev->dev, "failed to set pin direction\n");
16152045	135	return -EINVAL;
c5dbcf8b	136	}
16152045 JN	137
16152045 JN	138	/* IRQ setup */
c5dbcf8b JL	139	ret = gpio_to_irq(data->gpio_pin);
	140	if (ret < 0) {
	141	dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
2a651822	142	return -EINVAL;
16152045	143	}
c5dbcf8b	144	data->irq = ret;
16152045 JN	145
	146	/* initialize PPS specific parts of the bookkeeping data structure. */
	147	data->info.mode = PPS_CAPTUREASSERT \| PPS_OFFSETASSERT \|
	148	PPS_ECHOASSERT \| PPS_CANWAIT \| PPS_TSFMT_TSPEC;
c5dbcf8b	149	if (data->capture_clear)
16152045 JN	150	data->info.mode \|= PPS_CAPTURECLEAR \| PPS_OFFSETCLEAR \|
	151	PPS_ECHOCLEAR;
	152	data->info.owner = THIS_MODULE;
	153	snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
	154	pdev->name, pdev->id);
	155
	156	/* register PPS source */
	157	pps_default_params = PPS_CAPTUREASSERT \| PPS_OFFSETASSERT;
c5dbcf8b	158	if (data->capture_clear)
16152045 JN	159	pps_default_params \|= PPS_CAPTURECLEAR \| PPS_OFFSETCLEAR;
	160	data->pps = pps_register_source(&data->info, pps_default_params);
	161	if (data->pps == NULL) {
c5dbcf8b JL	162	dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
c5dbcf8b JL	163	data->irq);
2a651822	164	return -EINVAL;
16152045 JN	165	}
16152045 JN	166
16152045	167	/* register IRQ interrupt handler */
c5dbcf8b JL	168	ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
c5dbcf8b JL	169	get_irqf_trigger_flags(data), data->info.name, data);
16152045 JN	170	if (ret) {
16152045 JN	171	pps_unregister_source(data->pps);
c5dbcf8b	172	dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
2a651822	173	return -EINVAL;
16152045 JN	174	}
	175
	176	platform_set_drvdata(pdev, data);
c5dbcf8b JL	177	dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
c5dbcf8b JL	178	data->irq);
16152045 JN	179
16152045 JN	180	return 0;
16152045 JN	181	}
	182
	183	static int pps_gpio_remove(struct platform_device *pdev)
	184	{
	185	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
16152045	186
16152045	187	pps_unregister_source(data->pps);
c5dbcf8b	188	dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
16152045 JN	189	return 0;
	190	}
	191
c5dbcf8b JL	192	static const struct of_device_id pps_gpio_dt_ids[] = {
	193	{ .compatible = "pps-gpio", },
	194	{ /* sentinel */ }
	195	};
	196	MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
	197
16152045 JN	198	static struct platform_driver pps_gpio_driver = {
16152045 JN	199	.probe = pps_gpio_probe,
0fe763c5	200	.remove = pps_gpio_remove,
16152045 JN	201	.driver = {
16152045 JN	202	.name = PPS_GPIO_NAME,
1a10bd94	203	.of_match_table = pps_gpio_dt_ids,
16152045 JN	204	},
	205	};
	206
05212be3	207	module_platform_driver(pps_gpio_driver);
16152045 JN	208	MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
	209	MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
	210	MODULE_DESCRIPTION("Use GPIO pin as PPS source");
	211	MODULE_LICENSE("GPL");
	212	MODULE_VERSION("1.0.0");