1 /*
2  * Copyright (C) Nokia Corporation
3  *
4  * Written by Timo Kokkonen <timo.t.kokkonen at nokia.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19  */
20 
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/slab.h>
24 #include <linux/kernel.h>
25 #include <linux/watchdog.h>
26 #include <linux/platform_device.h>
27 #include <linux/i2c/twl.h>
28 
29 #define TWL4030_WATCHDOG_CFG_REG_OFFS	0x3
30 
31 static bool nowayout = WATCHDOG_NOWAYOUT;
32 module_param(nowayout, bool, 0);
33 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
34 	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
35 
36 static int twl4030_wdt_write(unsigned char val)
37 {
38 	return twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER, val,
39 					TWL4030_WATCHDOG_CFG_REG_OFFS);
40 }
41 
42 static int twl4030_wdt_start(struct watchdog_device *wdt)
43 {
44 	return twl4030_wdt_write(wdt->timeout + 1);
45 }
46 
47 static int twl4030_wdt_stop(struct watchdog_device *wdt)
48 {
49 	return twl4030_wdt_write(0);
50 }
51 
52 static int twl4030_wdt_set_timeout(struct watchdog_device *wdt,
53 				   unsigned int timeout)
54 {
55 	wdt->timeout = timeout;
56 	return 0;
57 }
58 
59 static const struct watchdog_info twl4030_wdt_info = {
60 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
61 	.identity = "TWL4030 Watchdog",
62 };
63 
64 static const struct watchdog_ops twl4030_wdt_ops = {
65 	.owner		= THIS_MODULE,
66 	.start		= twl4030_wdt_start,
67 	.stop		= twl4030_wdt_stop,
68 	.set_timeout	= twl4030_wdt_set_timeout,
69 };
70 
71 static int twl4030_wdt_probe(struct platform_device *pdev)
72 {
73 	int ret = 0;
74 	struct watchdog_device *wdt;
75 
76 	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
77 	if (!wdt)
78 		return -ENOMEM;
79 
80 	wdt->info		= &twl4030_wdt_info;
81 	wdt->ops		= &twl4030_wdt_ops;
82 	wdt->status		= 0;
83 	wdt->timeout		= 30;
84 	wdt->min_timeout	= 1;
85 	wdt->max_timeout	= 30;
86 	wdt->parent = &pdev->dev;
87 
88 	watchdog_set_nowayout(wdt, nowayout);
89 	platform_set_drvdata(pdev, wdt);
90 
91 	twl4030_wdt_stop(wdt);
92 
93 	ret = watchdog_register_device(wdt);
94 	if (ret)
95 		return ret;
96 
97 	return 0;
98 }
99 
100 static int twl4030_wdt_remove(struct platform_device *pdev)
101 {
102 	struct watchdog_device *wdt = platform_get_drvdata(pdev);
103 
104 	watchdog_unregister_device(wdt);
105 
106 	return 0;
107 }
108 
109 #ifdef CONFIG_PM
110 static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
111 {
112 	struct watchdog_device *wdt = platform_get_drvdata(pdev);
113 	if (watchdog_active(wdt))
114 		return twl4030_wdt_stop(wdt);
115 
116 	return 0;
117 }
118 
119 static int twl4030_wdt_resume(struct platform_device *pdev)
120 {
121 	struct watchdog_device *wdt = platform_get_drvdata(pdev);
122 	if (watchdog_active(wdt))
123 		return twl4030_wdt_start(wdt);
124 
125 	return 0;
126 }
127 #else
128 #define twl4030_wdt_suspend        NULL
129 #define twl4030_wdt_resume         NULL
130 #endif
131 
132 static const struct of_device_id twl_wdt_of_match[] = {
133 	{ .compatible = "ti,twl4030-wdt", },
134 	{ },
135 };
136 MODULE_DEVICE_TABLE(of, twl_wdt_of_match);
137 
138 static struct platform_driver twl4030_wdt_driver = {
139 	.probe		= twl4030_wdt_probe,
140 	.remove		= twl4030_wdt_remove,
141 	.suspend	= twl4030_wdt_suspend,
142 	.resume		= twl4030_wdt_resume,
143 	.driver		= {
144 		.name		= "twl4030_wdt",
145 		.of_match_table	= twl_wdt_of_match,
146 	},
147 };
148 
149 module_platform_driver(twl4030_wdt_driver);
150 
151 MODULE_AUTHOR("Nokia Corporation");
152 MODULE_LICENSE("GPL");
153 MODULE_ALIAS("platform:twl4030_wdt");
154 
155