aboutsummaryrefslogtreecommitdiff
path: root/drivers/watchdog/da9055_wdt.c
blob: 575f37a965a471ba93a77a4bdda5840f0dc7b8e0 (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
/*
 * System monitoring driver for DA9055 PMICs.
 *
 * Copyright(c) 2012 Dialog Semiconductor Ltd.
 *
 * Author: David Dajun Chen <dchen@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/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/delay.h>

#include <linux/mfd/da9055/core.h>
#include <linux/mfd/da9055/reg.h>

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
		 "Watchdog cannot be stopped once started (default="
		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

#define DA9055_DEF_TIMEOUT	4
#define DA9055_TWDMIN		256

struct da9055_wdt_data {
	struct watchdog_device wdt;
	struct da9055 *da9055;
	struct kref kref;
};

static const struct {
	u8 reg_val;
	int user_time;  /* In seconds */
} da9055_wdt_maps[] = {
	{ 0, 0 },
	{ 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 da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
				  unsigned int timeout)
{
	struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
	struct da9055 *da9055 = driver_data->da9055;
	int ret, i;

	for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
		if (da9055_wdt_maps[i].user_time == timeout)
			break;

	if (i == ARRAY_SIZE(da9055_wdt_maps))
		ret = -EINVAL;
	else
		ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
					DA9055_TWDSCALE_MASK,
					da9055_wdt_maps[i].reg_val <<
					DA9055_TWDSCALE_SHIFT);
	if (ret < 0) {
		dev_err(da9055->dev,
			"Failed to update timescale bit, %d\n", ret);
		return ret;
	}

	wdt_dev->timeout = timeout;

	return 0;
}

static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
{
	struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
	struct da9055 *da9055 = driver_data->da9055;

	/*
	 * We have a minimum time for watchdog window called TWDMIN. A write
	 * to the watchdog before this elapsed time will cause an error.
	 */
	mdelay(DA9055_TWDMIN);

	/* Reset the watchdog timer */
	return da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
				 DA9055_WATCHDOG_MASK, 1);
}

static void da9055_wdt_release_resources(struct kref *r)
{
}

static void da9055_wdt_ref(struct watchdog_device *wdt_dev)
{
	struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);

	kref_get(&driver_data->kref);
}

static void da9055_wdt_unref(struct watchdog_device *wdt_dev)
{
	struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);

	kref_put(&driver_data->kref, da9055_wdt_release_resources);
}

static int da9055_wdt_start(struct watchdog_device *wdt_dev)
{
	return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
}

static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
{
	return da9055_wdt_set_timeout(wdt_dev, 0);
}

static struct watchdog_info da9055_wdt_info = {
	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
	.identity	= "DA9055 Watchdog",
};

static const struct watchdog_ops da9055_wdt_ops = {
	.owner = THIS_MODULE,
	.start = da9055_wdt_start,
	.stop = da9055_wdt_stop,
	.ping = da9055_wdt_ping,
	.set_timeout = da9055_wdt_set_timeout,
	.ref = da9055_wdt_ref,
	.unref = da9055_wdt_unref,
};

static int da9055_wdt_probe(struct platform_device *pdev)
{
	struct da9055 *da9055 = dev_get_drvdata(pdev->dev.parent);
	struct da9055_wdt_data *driver_data;
	struct watchdog_device *da9055_wdt;
	int ret;

	driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
				   GFP_KERNEL);
	if (!driver_data) {
		dev_err(da9055->dev, "Failed to allocate watchdog device\n");
		return -ENOMEM;
	}

	driver_data->da9055 = da9055;

	da9055_wdt = &driver_data->wdt;

	da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
	da9055_wdt->info = &da9055_wdt_info;
	da9055_wdt->ops = &da9055_wdt_ops;
	watchdog_set_nowayout(da9055_wdt, nowayout);
	watchdog_set_drvdata(da9055_wdt, driver_data);

	kref_init(&driver_data->kref);

	ret = da9055_wdt_stop(da9055_wdt);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret);
		goto err;
	}

	platform_set_drvdata(pdev, driver_data);

	ret = watchdog_register_device(&driver_data->wdt);
	if (ret != 0)
		dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
			ret);

err:
	return ret;
}

static int da9055_wdt_remove(struct platform_device *pdev)
{
	struct da9055_wdt_data *driver_data = platform_get_drvdata(pdev);

	watchdog_unregister_device(&driver_data->wdt);
	kref_put(&driver_data->kref, da9055_wdt_release_resources);

	return 0;
}

static struct platform_driver da9055_wdt_driver = {
	.probe = da9055_wdt_probe,
	.remove = da9055_wdt_remove,
	.driver = {
		.name	= "da9055-watchdog",
	},
};

module_platform_driver(da9055_wdt_driver);

MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
MODULE_DESCRIPTION("DA9055 watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da9055-watchdog");