summaryrefslogtreecommitdiff
path: root/drivers/watchdog/da9052_wdt.c
blob: 3f75129eb0a9f06cd0a7d194a3c390f5ee9bfd3f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
/*
 * 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/delay.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)
{
	struct da9052_wdt_data *driver_data =
		container_of(r, struct da9052_wdt_data, kref);

	kfree(driver_data);
}

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 __devinit 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) {
		dev_err(da9052->dev, "Unable to alloacate watchdog device\n");
		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;
	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;
	}

	dev_set_drvdata(&pdev->dev, driver_data);
err:
	return ret;
}

static int __devexit da9052_wdt_remove(struct platform_device *pdev)
{
	struct da9052_wdt_data *driver_data = dev_get_drvdata(&pdev->dev);

	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 = __devexit_p(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");