summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/twl4030_wdt.c
blob: 0764c6239b98c8bb7793aca5c4b4486d79d7dac0 (plain) (blame)
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
252
253
254
255
256
257
258
259
260
261
262
263
264
265
/*
 * Copyright (C) Nokia Corporation
 *
 * Written by Timo Kokkonen <timo.t.kokkonen at nokia.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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
#include <linux/i2c/twl.h>

#define TWL4030_WATCHDOG_CFG_REG_OFFS	0x3

#define TWL4030_WDT_STATE_OPEN		0x1
#define TWL4030_WDT_STATE_ACTIVE	0x8

static struct platform_device *twl4030_wdt_dev;

struct twl4030_wdt {
	struct miscdevice	miscdev;
	int			timer_margin;
	unsigned long		state;
};

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

static int twl4030_wdt_write(unsigned char val)
{
	return twl_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, val,
					TWL4030_WATCHDOG_CFG_REG_OFFS);
}

static int twl4030_wdt_enable(struct twl4030_wdt *wdt)
{
	return twl4030_wdt_write(wdt->timer_margin + 1);
}

static int twl4030_wdt_disable(struct twl4030_wdt *wdt)
{
	return twl4030_wdt_write(0);
}

static int twl4030_wdt_set_timeout(struct twl4030_wdt *wdt, int timeout)
{
	if (timeout < 0 || timeout > 30) {
		dev_warn(wdt->miscdev.parent,
			"Timeout can only be in the range [0-30] seconds");
		return -EINVAL;
	}
	wdt->timer_margin = timeout;
	return twl4030_wdt_enable(wdt);
}

static ssize_t twl4030_wdt_write_fop(struct file *file,
		const char __user *data, size_t len, loff_t *ppos)
{
	struct twl4030_wdt *wdt = file->private_data;

	if (len)
		twl4030_wdt_enable(wdt);

	return len;
}

static long twl4030_wdt_ioctl(struct file *file,
		unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_margin;
	struct twl4030_wdt *wdt = file->private_data;

	static const struct watchdog_info twl4030_wd_ident = {
		.identity = "TWL4030 Watchdog",
		.options = WDIOF_SETTIMEOUT,
		.firmware_version = 0,
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &twl4030_wd_ident,
				sizeof(twl4030_wd_ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);

	case WDIOC_KEEPALIVE:
		twl4030_wdt_enable(wdt);
		break;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_margin, p))
			return -EFAULT;
		if (twl4030_wdt_set_timeout(wdt, new_margin))
			return -EINVAL;
		return put_user(wdt->timer_margin, p);

	case WDIOC_GETTIMEOUT:
		return put_user(wdt->timer_margin, p);

	default:
		return -ENOTTY;
	}

	return 0;
}

static int twl4030_wdt_open(struct inode *inode, struct file *file)
{
	struct twl4030_wdt *wdt = platform_get_drvdata(twl4030_wdt_dev);

	/* /dev/watchdog can only be opened once */
	if (test_and_set_bit(0, &wdt->state))
		return -EBUSY;

	wdt->state |= TWL4030_WDT_STATE_ACTIVE;
	file->private_data = (void *) wdt;

	twl4030_wdt_enable(wdt);
	return nonseekable_open(inode, file);
}

static int twl4030_wdt_release(struct inode *inode, struct file *file)
{
	struct twl4030_wdt *wdt = file->private_data;
	if (nowayout) {
		dev_alert(wdt->miscdev.parent,
		       "Unexpected close, watchdog still running!\n");
		twl4030_wdt_enable(wdt);
	} else {
		if (twl4030_wdt_disable(wdt))
			return -EFAULT;
		wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
	}

	clear_bit(0, &wdt->state);
	return 0;
}

static const struct file_operations twl4030_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.open		= twl4030_wdt_open,
	.release	= twl4030_wdt_release,
	.unlocked_ioctl	= twl4030_wdt_ioctl,
	.write		= twl4030_wdt_write_fop,
};

static int __devinit twl4030_wdt_probe(struct platform_device *pdev)
{
	int ret = 0;
	struct twl4030_wdt *wdt;

	wdt = kzalloc(sizeof(struct twl4030_wdt), GFP_KERNEL);
	if (!wdt)
		return -ENOMEM;

	wdt->state		= 0;
	wdt->timer_margin	= 30;
	wdt->miscdev.parent	= &pdev->dev;
	wdt->miscdev.fops	= &twl4030_wdt_fops;
	wdt->miscdev.minor	= WATCHDOG_MINOR;
	wdt->miscdev.name	= "watchdog";

	platform_set_drvdata(pdev, wdt);

	twl4030_wdt_dev = pdev;

	twl4030_wdt_disable(wdt);

	ret = misc_register(&wdt->miscdev);
	if (ret) {
		dev_err(wdt->miscdev.parent,
			"Failed to register misc device\n");
		platform_set_drvdata(pdev, NULL);
		kfree(wdt);
		twl4030_wdt_dev = NULL;
		return ret;
	}
	return 0;
}

static int __devexit twl4030_wdt_remove(struct platform_device *pdev)
{
	struct twl4030_wdt *wdt = platform_get_drvdata(pdev);

	if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
		if (twl4030_wdt_disable(wdt))
			return -EFAULT;

	wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
	misc_deregister(&wdt->miscdev);

	platform_set_drvdata(pdev, NULL);
	kfree(wdt);
	twl4030_wdt_dev = NULL;

	return 0;
}

#ifdef CONFIG_PM
static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
	if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
		return twl4030_wdt_disable(wdt);

	return 0;
}

static int twl4030_wdt_resume(struct platform_device *pdev)
{
	struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
	if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
		return twl4030_wdt_enable(wdt);

	return 0;
}
#else
#define twl4030_wdt_suspend        NULL
#define twl4030_wdt_resume         NULL
#endif

static struct platform_driver twl4030_wdt_driver = {
	.probe		= twl4030_wdt_probe,
	.remove		= __devexit_p(twl4030_wdt_remove),
	.suspend	= twl4030_wdt_suspend,
	.resume		= twl4030_wdt_resume,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= "twl4030_wdt",
	},
};

module_platform_driver(twl4030_wdt_driver);

MODULE_AUTHOR("Nokia Corporation");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:twl4030_wdt");