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#include <linux/delay.h>
 25
 26#include <linux/mfd/da9052/reg.h>
 27#include <linux/mfd/da9052/da9052.h>
 28
 29#define DA9052_DEF_TIMEOUT	4
 30#define DA9052_TWDMIN		256
 31
 32struct da9052_wdt_data {
 33	struct watchdog_device wdt;
 34	struct da9052 *da9052;
 35	struct kref kref;
 36	unsigned long jpast;
 37};
 38
 39static const struct {
 40	u8 reg_val;
 41	int time;  /* Seconds */
 42} da9052_wdt_maps[] = {
 43	{ 1, 2 },
 44	{ 2, 4 },
 45	{ 3, 8 },
 46	{ 4, 16 },
 47	{ 5, 32 },
 48	{ 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
 49	{ 6, 65 },
 50	{ 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
 51	{ 7, 131 },
 52};
 53
 54
 55static void da9052_wdt_release_resources(struct kref *r)
 56{
 57	struct da9052_wdt_data *driver_data =
 58		container_of(r, struct da9052_wdt_data, kref);
 59
 60	kfree(driver_data);
 61}
 62
 63static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
 64				  unsigned int timeout)
 65{
 66	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 67	struct da9052 *da9052 = driver_data->da9052;
 68	int ret, i;
 69
 70	/*
 71	 * Disable the Watchdog timer before setting
 72	 * new time out.
 73	 */
 74	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 75				DA9052_CONTROLD_TWDSCALE, 0);
 76	if (ret < 0) {
 77		dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
 78			ret);
 79		return ret;
 80	}
 81	if (timeout) {
 82		/*
 83		 * To change the timeout, da9052 needs to
 84		 * be disabled for at least 150 us.
 85		 */
 86		udelay(150);
 87
 88		/* Set the desired timeout */
 89		for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
 90			if (da9052_wdt_maps[i].time == timeout)
 91				break;
 92
 93		if (i == ARRAY_SIZE(da9052_wdt_maps))
 94			ret = -EINVAL;
 95		else
 96			ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 97						DA9052_CONTROLD_TWDSCALE,
 98						da9052_wdt_maps[i].reg_val);
 99		if (ret < 0) {
100			dev_err(da9052->dev,
101				"Failed to update timescale bit, %d\n", ret);
102			return ret;
103		}
104
105		wdt_dev->timeout = timeout;
106		driver_data->jpast = jiffies;
107	}
108
109	return 0;
110}
111
112static void da9052_wdt_ref(struct watchdog_device *wdt_dev)
113{
114	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
115
116	kref_get(&driver_data->kref);
117}
118
119static void da9052_wdt_unref(struct watchdog_device *wdt_dev)
120{
121	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
122
123	kref_put(&driver_data->kref, da9052_wdt_release_resources);
124}
125
126static int da9052_wdt_start(struct watchdog_device *wdt_dev)
127{
128	return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
129}
130
131static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
132{
133	return da9052_wdt_set_timeout(wdt_dev, 0);
134}
135
136static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
137{
138	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
139	struct da9052 *da9052 = driver_data->da9052;
140	unsigned long msec, jnow = jiffies;
141	int ret;
142
143	/*
144	 * We have a minimum time for watchdog window called TWDMIN. A write
145	 * to the watchdog before this elapsed time should cause an error.
146	 */
147	msec = (jnow - driver_data->jpast) * 1000/HZ;
148	if (msec < DA9052_TWDMIN)
149		mdelay(msec);
150
151	/* Reset the watchdog timer */
152	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
153				DA9052_CONTROLD_WATCHDOG, 1 << 7);
154	if (ret < 0)
155		goto err_strobe;
156
157	/*
158	 * FIXME: Reset the watchdog core, in general PMIC
159	 * is supposed to do this
160	 */
161	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
162				DA9052_CONTROLD_WATCHDOG, 0 << 7);
163err_strobe:
164	return ret;
165}
166
167static struct watchdog_info da9052_wdt_info = {
168	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
169	.identity	= "DA9052 Watchdog",
170};
171
172static const struct watchdog_ops da9052_wdt_ops = {
173	.owner = THIS_MODULE,
174	.start = da9052_wdt_start,
175	.stop = da9052_wdt_stop,
176	.ping = da9052_wdt_ping,
177	.set_timeout = da9052_wdt_set_timeout,
178	.ref = da9052_wdt_ref,
179	.unref = da9052_wdt_unref,
180};
181
182
183static int __devinit da9052_wdt_probe(struct platform_device *pdev)
184{
185	struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent);
186	struct da9052_wdt_data *driver_data;
187	struct watchdog_device *da9052_wdt;
188	int ret;
189
190	driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
191				   GFP_KERNEL);
192	if (!driver_data) {
193		dev_err(da9052->dev, "Unable to alloacate watchdog device\n");
194		ret = -ENOMEM;
195		goto err;
196	}
197	driver_data->da9052 = da9052;
198
199	da9052_wdt = &driver_data->wdt;
200
201	da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
202	da9052_wdt->info = &da9052_wdt_info;
203	da9052_wdt->ops = &da9052_wdt_ops;
204	watchdog_set_drvdata(da9052_wdt, driver_data);
205
206	kref_init(&driver_data->kref);
207
208	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
209				DA9052_CONTROLD_TWDSCALE, 0);
210	if (ret < 0) {
211		dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n",
212			ret);
213		goto err;
214	}
215
216	ret = watchdog_register_device(&driver_data->wdt);
217	if (ret != 0) {
218		dev_err(da9052->dev, "watchdog_register_device() failed: %d\n",
219			ret);
220		goto err;
221	}
222
223	dev_set_drvdata(&pdev->dev, driver_data);
224err:
225	return ret;
226}
227
228static int __devexit da9052_wdt_remove(struct platform_device *pdev)
229{
230	struct da9052_wdt_data *driver_data = dev_get_drvdata(&pdev->dev);
231
232	watchdog_unregister_device(&driver_data->wdt);
233	kref_put(&driver_data->kref, da9052_wdt_release_resources);
234
235	return 0;
236}
237
238static struct platform_driver da9052_wdt_driver = {
239	.probe = da9052_wdt_probe,
240	.remove = __devexit_p(da9052_wdt_remove),
241	.driver = {
242		.name	= "da9052-watchdog",
243	},
244};
245
246module_platform_driver(da9052_wdt_driver);
247
248MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
249MODULE_DESCRIPTION("DA9052 SM Device Driver");
250MODULE_LICENSE("GPL");
251MODULE_ALIAS("platform:da9052-watchdog");