summaryrefslogtreecommitdiff
path: root/drivers/watchdog/rn5t618_wdt.c
blob: 21fcb36f9074a4966b44ac13d2e82d5d0c556ff8 (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
/*
 * Watchdog driver for Ricoh RN5T618 PMIC
 *
 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/device.h>
#include <linux/mfd/rn5t618.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>

#define DRIVER_NAME "rn5t618-wdt"

static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int timeout;

module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds");

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

struct rn5t618_wdt {
	struct watchdog_device wdt_dev;
	struct rn5t618 *rn5t618;
};

/*
 * This array encodes the values of WDOGTIM field for the supported
 * watchdog expiration times. If the watchdog is not accessed before
 * the timer expiration, the PMU generates an interrupt and if the CPU
 * doesn't clear it within one second the system is restarted.
 */
static const struct {
	u8 reg_val;
	unsigned int time;
} rn5t618_wdt_map[] = {
	{ 0, 1 },
	{ 1, 8 },
	{ 2, 32 },
	{ 3, 128 },
};

static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
				   unsigned int t)
{
	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
	int ret, i;

	for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
		if (rn5t618_wdt_map[i].time + 1 >= t)
			break;
	}

	if (i == ARRAY_SIZE(rn5t618_wdt_map))
		return -EINVAL;

	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
				 RN5T618_WATCHDOG_WDOGTIM_M,
				 rn5t618_wdt_map[i].reg_val);
	if (!ret)
		wdt_dev->timeout = rn5t618_wdt_map[i].time;

	return ret;
}

static int rn5t618_wdt_start(struct watchdog_device *wdt_dev)
{
	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
	int ret;

	ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
	if (ret)
		return ret;

	/* enable repower-on */
	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT,
				 RN5T618_REPCNT_REPWRON,
				 RN5T618_REPCNT_REPWRON);
	if (ret)
		return ret;

	/* enable watchdog */
	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
				 RN5T618_WATCHDOG_WDOGEN,
				 RN5T618_WATCHDOG_WDOGEN);
	if (ret)
		return ret;

	/* enable watchdog interrupt */
	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN,
				  RN5T618_PWRIRQ_IR_WDOG,
				  RN5T618_PWRIRQ_IR_WDOG);
}

static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev)
{
	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);

	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
				  RN5T618_WATCHDOG_WDOGEN, 0);
}

static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev)
{
	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
	unsigned int val;
	int ret;

	/* The counter is restarted after a R/W access to watchdog register */
	ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val);
	if (ret)
		return ret;

	ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val);
	if (ret)
		return ret;

	/* Clear pending watchdog interrupt */
	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ,
				  RN5T618_PWRIRQ_IR_WDOG, 0);
}

static const struct watchdog_info rn5t618_wdt_info = {
	.options	= WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
			  WDIOF_KEEPALIVEPING,
	.identity	= DRIVER_NAME,
};

static const struct watchdog_ops rn5t618_wdt_ops = {
	.owner          = THIS_MODULE,
	.start          = rn5t618_wdt_start,
	.stop           = rn5t618_wdt_stop,
	.ping           = rn5t618_wdt_ping,
	.set_timeout    = rn5t618_wdt_set_timeout,
};

static int rn5t618_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct rn5t618 *rn5t618 = dev_get_drvdata(dev->parent);
	struct rn5t618_wdt *wdt;
	int min_timeout, max_timeout;

	wdt = devm_kzalloc(dev, sizeof(struct rn5t618_wdt), GFP_KERNEL);
	if (!wdt)
		return -ENOMEM;

	min_timeout = rn5t618_wdt_map[0].time;
	max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time;

	wdt->rn5t618 = rn5t618;
	wdt->wdt_dev.info = &rn5t618_wdt_info;
	wdt->wdt_dev.ops = &rn5t618_wdt_ops;
	wdt->wdt_dev.min_timeout = min_timeout;
	wdt->wdt_dev.max_timeout = max_timeout;
	wdt->wdt_dev.timeout = max_timeout;
	wdt->wdt_dev.parent = dev;

	watchdog_set_drvdata(&wdt->wdt_dev, wdt);
	watchdog_init_timeout(&wdt->wdt_dev, timeout, dev);
	watchdog_set_nowayout(&wdt->wdt_dev, nowayout);

	platform_set_drvdata(pdev, wdt);

	return watchdog_register_device(&wdt->wdt_dev);
}

static int rn5t618_wdt_remove(struct platform_device *pdev)
{
	struct rn5t618_wdt *wdt = platform_get_drvdata(pdev);

	watchdog_unregister_device(&wdt->wdt_dev);

	return 0;
}

static struct platform_driver rn5t618_wdt_driver = {
	.probe = rn5t618_wdt_probe,
	.remove = rn5t618_wdt_remove,
	.driver = {
		.name	= DRIVER_NAME,
	},
};

module_platform_driver(rn5t618_wdt_driver);

MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
MODULE_DESCRIPTION("RN5T618 watchdog driver");
MODULE_LICENSE("GPL v2");