[deliverable/linux.git] / drivers / watchdog / da9052_wdt.c

/*
 * System monitoring driver for DA9052 PMICs.
 *
 * Copyright(c) 2012 Dialog Semiconductor Ltd.
 *
 * Author: Anthony Olech <Anthony.Olech@diasemi.com>
 *
 * 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.
 *
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <linux/platform_device.h>
#include <linux/time.h>
#include <linux/watchdog.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>

#include <linux/mfd/da9052/reg.h>
#include <linux/mfd/da9052/da9052.h>

#define DA9052_DEF_TIMEOUT	4
#define DA9052_TWDMIN		256

struct da9052_wdt_data {
	struct watchdog_device wdt;
	struct da9052 *da9052;
	struct kref kref;
	unsigned long jpast;
};

static const struct {
	u8 reg_val;
	int time;  /* Seconds */
} da9052_wdt_maps[] = {
	{ 1, 2 },
	{ 2, 4 },
	{ 3, 8 },
	{ 4, 16 },
	{ 5, 32 },
	{ 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
	{ 6, 65 },
	{ 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
	{ 7, 131 },
};


static void da9052_wdt_release_resources(struct kref *r)
{
}

static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
				  unsigned int timeout)
{
	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
	struct da9052 *da9052 = driver_data->da9052;
	int ret, i;

	/*
	 * Disable the Watchdog timer before setting
	 * new time out.
	 */
	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
				DA9052_CONTROLD_TWDSCALE, 0);
	if (ret < 0) {
		dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
			ret);
		return ret;
	}
	if (timeout) {
		/*
		 * To change the timeout, da9052 needs to
		 * be disabled for at least 150 us.
		 */
		udelay(150);

		/* Set the desired timeout */
		for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
			if (da9052_wdt_maps[i].time == timeout)
				break;

		if (i == ARRAY_SIZE(da9052_wdt_maps))
			ret = -EINVAL;
		else
			ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
						DA9052_CONTROLD_TWDSCALE,
						da9052_wdt_maps[i].reg_val);
		if (ret < 0) {
			dev_err(da9052->dev,
				"Failed to update timescale bit, %d\n", ret);
			return ret;
		}

		wdt_dev->timeout = timeout;
		driver_data->jpast = jiffies;
	}

	return 0;
}

static void da9052_wdt_ref(struct watchdog_device *wdt_dev)
{
	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);

	kref_get(&driver_data->kref);
}

static void da9052_wdt_unref(struct watchdog_device *wdt_dev)
{
	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);

	kref_put(&driver_data->kref, da9052_wdt_release_resources);
}

static int da9052_wdt_start(struct watchdog_device *wdt_dev)
{
	return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
}

static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
{
	return da9052_wdt_set_timeout(wdt_dev, 0);
}

static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
{
	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
	struct da9052 *da9052 = driver_data->da9052;
	unsigned long msec, jnow = jiffies;
	int ret;

	/*
	 * We have a minimum time for watchdog window called TWDMIN. A write
	 * to the watchdog before this elapsed time should cause an error.
	 */
	msec = (jnow - driver_data->jpast) * 1000/HZ;
	if (msec < DA9052_TWDMIN)
		mdelay(msec);

	/* Reset the watchdog timer */
	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
				DA9052_CONTROLD_WATCHDOG, 1 << 7);
	if (ret < 0)
		goto err_strobe;

	/*
	 * FIXME: Reset the watchdog core, in general PMIC
	 * is supposed to do this
	 */
	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
				DA9052_CONTROLD_WATCHDOG, 0 << 7);
err_strobe:
	return ret;
}

static struct watchdog_info da9052_wdt_info = {
	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
	.identity	= "DA9052 Watchdog",
};

static const struct watchdog_ops da9052_wdt_ops = {
	.owner = THIS_MODULE,
	.start = da9052_wdt_start,
	.stop = da9052_wdt_stop,
	.ping = da9052_wdt_ping,
	.set_timeout = da9052_wdt_set_timeout,
	.ref = da9052_wdt_ref,
	.unref = da9052_wdt_unref,
};


static int da9052_wdt_probe(struct platform_device *pdev)
{
	struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent);
	struct da9052_wdt_data *driver_data;
	struct watchdog_device *da9052_wdt;
	int ret;

	driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
				   GFP_KERNEL);
	if (!driver_data) {
		ret = -ENOMEM;
		goto err;
	}
	driver_data->da9052 = da9052;

	da9052_wdt = &driver_data->wdt;

	da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
	da9052_wdt->info = &da9052_wdt_info;
	da9052_wdt->ops = &da9052_wdt_ops;
	da9052_wdt->parent = &pdev->dev;
	watchdog_set_drvdata(da9052_wdt, driver_data);

	kref_init(&driver_data->kref);

	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
				DA9052_CONTROLD_TWDSCALE, 0);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n",
			ret);
		goto err;
	}

	ret = watchdog_register_device(&driver_data->wdt);
	if (ret != 0) {
		dev_err(da9052->dev, "watchdog_register_device() failed: %d\n",
			ret);
		goto err;
	}

	platform_set_drvdata(pdev, driver_data);
err:
	return ret;
}

static int da9052_wdt_remove(struct platform_device *pdev)
{
	struct da9052_wdt_data *driver_data = platform_get_drvdata(pdev);

	watchdog_unregister_device(&driver_data->wdt);
	kref_put(&driver_data->kref, da9052_wdt_release_resources);

	return 0;
}

static struct platform_driver da9052_wdt_driver = {
	.probe = da9052_wdt_probe,
	.remove = da9052_wdt_remove,
	.driver = {
		.name	= "da9052-watchdog",
	},
};

module_platform_driver(da9052_wdt_driver);

MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
MODULE_DESCRIPTION("DA9052 SM Device Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da9052-watchdog");
Commit	Line	Data
664a0d78 AJ	1	/*
	2	* System monitoring driver for DA9052 PMICs.
	3	*
	4	* Copyright(c) 2012 Dialog Semiconductor Ltd.
	5	*
	6	* Author: Anthony Olech <Anthony.Olech@diasemi.com>
	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	*/
	14
	15	#include <linux/module.h>
	16	#include <linux/delay.h>
	17	#include <linux/uaccess.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/time.h>
	20	#include <linux/watchdog.h>
	21	#include <linux/types.h>
	22	#include <linux/kernel.h>
	23	#include <linux/jiffies.h>
664a0d78 AJ	24
	25	#include <linux/mfd/da9052/reg.h>
	26	#include <linux/mfd/da9052/da9052.h>
	27
	28	#define DA9052_DEF_TIMEOUT 4
	29	#define DA9052_TWDMIN 256
	30
	31	struct da9052_wdt_data {
	32	struct watchdog_device wdt;
	33	struct da9052 *da9052;
	34	struct kref kref;
	35	unsigned long jpast;
	36	};
	37
	38	static const struct {
	39	u8 reg_val;
	40	int time; /* Seconds */
	41	} da9052_wdt_maps[] = {
	42	{ 1, 2 },
	43	{ 2, 4 },
	44	{ 3, 8 },
	45	{ 4, 16 },
	46	{ 5, 32 },
	47	{ 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */
	48	{ 6, 65 },
	49	{ 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */
	50	{ 7, 131 },
	51	};
	52
	53
	54	static void da9052_wdt_release_resources(struct kref *r)
	55	{
664a0d78 AJ	56	}
	57
	58	static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
	59	unsigned int timeout)
	60	{
	61	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
	62	struct da9052 *da9052 = driver_data->da9052;
	63	int ret, i;
	64
	65	/*
	66	* Disable the Watchdog timer before setting
	67	* new time out.
	68	*/
	69	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
	70	DA9052_CONTROLD_TWDSCALE, 0);
	71	if (ret < 0) {
	72	dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
	73	ret);
	74	return ret;
	75	}
	76	if (timeout) {
	77	/*
	78	* To change the timeout, da9052 needs to
	79	* be disabled for at least 150 us.
	80	*/
	81	udelay(150);
	82
	83	/* Set the desired timeout */
	84	for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
	85	if (da9052_wdt_maps[i].time == timeout)
	86	break;
	87
	88	if (i == ARRAY_SIZE(da9052_wdt_maps))
	89	ret = -EINVAL;
	90	else
	91	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
	92	DA9052_CONTROLD_TWDSCALE,
	93	da9052_wdt_maps[i].reg_val);
	94	if (ret < 0) {
	95	dev_err(da9052->dev,
	96	"Failed to update timescale bit, %d\n", ret);
	97	return ret;
	98	}
	99
	100	wdt_dev->timeout = timeout;
	101	driver_data->jpast = jiffies;
	102	}
	103
	104	return 0;
	105	}
	106
	107	static void da9052_wdt_ref(struct watchdog_device *wdt_dev)
	108	{
	109	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
	110
	111	kref_get(&driver_data->kref);
	112	}
	113
	114	static void da9052_wdt_unref(struct watchdog_device *wdt_dev)
	115	{
	116	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
	117
	118	kref_put(&driver_data->kref, da9052_wdt_release_resources);
	119	}
120
121	static int da9052_wdt_start(struct watchdog_device *wdt_dev)
122	{
123	return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
124	}
125
126	static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
127	{
128	return da9052_wdt_set_timeout(wdt_dev, 0);
129	}
130
131	static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
132	{
133	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
134	struct da9052 *da9052 = driver_data->da9052;
135	unsigned long msec, jnow = jiffies;
136	int ret;
137
138	/*
139	* We have a minimum time for watchdog window called TWDMIN. A write
140	* to the watchdog before this elapsed time should cause an error.
141	*/
142	msec = (jnow - driver_data->jpast) * 1000/HZ;
143	if (msec < DA9052_TWDMIN)
144	mdelay(msec);
145
146	/* Reset the watchdog timer */
147	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
148	DA9052_CONTROLD_WATCHDOG, 1 << 7);
149	if (ret < 0)
150	goto err_strobe;
151
152	/*
153	* FIXME: Reset the watchdog core, in general PMIC
154	* is supposed to do this
155	*/
156	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
157	DA9052_CONTROLD_WATCHDOG, 0 << 7);
158	err_strobe:
159	return ret;
160	}
161
162	static struct watchdog_info da9052_wdt_info = {
163	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
164	.identity = "DA9052 Watchdog",
165	};
166
167	static const struct watchdog_ops da9052_wdt_ops = {
168	.owner = THIS_MODULE,
169	.start = da9052_wdt_start,
170	.stop = da9052_wdt_stop,
171	.ping = da9052_wdt_ping,
172	.set_timeout = da9052_wdt_set_timeout,
173	.ref = da9052_wdt_ref,
174	.unref = da9052_wdt_unref,
175	};
176
177
2d991a16	178	static int da9052_wdt_probe(struct platform_device *pdev)
664a0d78 AJ	179	{
	180	struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent);
	181	struct da9052_wdt_data *driver_data;
	182	struct watchdog_device *da9052_wdt;
	183	int ret;
	184
	185	driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
	186	GFP_KERNEL);
	187	if (!driver_data) {
664a0d78 AJ	188	ret = -ENOMEM;
	189	goto err;
	190	}
	191	driver_data->da9052 = da9052;
	192
	193	da9052_wdt = &driver_data->wdt;
	194
	195	da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
	196	da9052_wdt->info = &da9052_wdt_info;
	197	da9052_wdt->ops = &da9052_wdt_ops;
6551881c	198	da9052_wdt->parent = &pdev->dev;
664a0d78 AJ	199	watchdog_set_drvdata(da9052_wdt, driver_data);
	200
	201	kref_init(&driver_data->kref);
	202
	203	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
	204	DA9052_CONTROLD_TWDSCALE, 0);
	205	if (ret < 0) {
	206	dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n",
	207	ret);
	208	goto err;
	209	}
	210
	211	ret = watchdog_register_device(&driver_data->wdt);
	212	if (ret != 0) {
	213	dev_err(da9052->dev, "watchdog_register_device() failed: %d\n",
	214	ret);
	215	goto err;
	216	}
	217
552a9641	218	platform_set_drvdata(pdev, driver_data);
664a0d78 AJ	219	err:
	220	return ret;
	221	}
	222
4b12b896	223	static int da9052_wdt_remove(struct platform_device *pdev)
664a0d78	224	{
552a9641	225	struct da9052_wdt_data *driver_data = platform_get_drvdata(pdev);
664a0d78 AJ	226
	227	watchdog_unregister_device(&driver_data->wdt);
	228	kref_put(&driver_data->kref, da9052_wdt_release_resources);
	229
	230	return 0;
	231	}
	232
	233	static struct platform_driver da9052_wdt_driver = {
	234	.probe = da9052_wdt_probe,
82268714	235	.remove = da9052_wdt_remove,
664a0d78 AJ	236	.driver = {
	237	.name = "da9052-watchdog",
	238	},
	239	};
	240
	241	module_platform_driver(da9052_wdt_driver);
	242
	243	MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
	244	MODULE_DESCRIPTION("DA9052 SM Device Driver");
	245	MODULE_LICENSE("GPL");
	246	MODULE_ALIAS("platform:da9052-watchdog");