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