aboutsummaryrefslogtreecommitdiff
path: root/drivers/watchdog/da9052_wdt.c
blob: d6d5006efa717df162a4746341467d96a677f412 (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
/*
 * 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;
	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 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 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)
		return ret;

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

static const 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,
};


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)
		return -ENOMEM;
	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);

	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);
		return ret;
	}

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

	return ret;
}

static struct platform_driver da9052_wdt_driver = {
	.probe = da9052_wdt_probe,
	.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");