1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) Nokia Corporation
4  *
5  * Written by Timo Kokkonen <timo.t.kokkonen at nokia.com>
6  */
7 
8 #include <linux/module.h>
9 #include <linux/types.h>
10 #include <linux/slab.h>
11 #include <linux/kernel.h>
12 #include <linux/mod_devicetable.h>
13 #include <linux/watchdog.h>
14 #include <linux/platform_device.h>
15 #include <linux/mfd/twl.h>
16 
17 #define TWL4030_WATCHDOG_CFG_REG_OFFS	0x3
18 
19 static bool nowayout = WATCHDOG_NOWAYOUT;
20 module_param(nowayout, bool, 0);
21 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
22 	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
23 
24 static int twl4030_wdt_write(unsigned char val)
25 {
26 	return twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER, val,
27 					TWL4030_WATCHDOG_CFG_REG_OFFS);
28 }
29 
30 static int twl4030_wdt_start(struct watchdog_device *wdt)
31 {
32 	return twl4030_wdt_write(wdt->timeout + 1);
33 }
34 
35 static int twl4030_wdt_stop(struct watchdog_device *wdt)
36 {
37 	return twl4030_wdt_write(0);
38 }
39 
40 static int twl4030_wdt_set_timeout(struct watchdog_device *wdt,
41 				   unsigned int timeout)
42 {
43 	wdt->timeout = timeout;
44 	return 0;
45 }
46 
47 static const struct watchdog_info twl4030_wdt_info = {
48 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
49 	.identity = "TWL4030 Watchdog",
50 };
51 
52 static const struct watchdog_ops twl4030_wdt_ops = {
53 	.owner		= THIS_MODULE,
54 	.start		= twl4030_wdt_start,
55 	.stop		= twl4030_wdt_stop,
56 	.set_timeout	= twl4030_wdt_set_timeout,
57 };
58 
59 static int twl4030_wdt_probe(struct platform_device *pdev)
60 {
61 	struct device *dev = &pdev->dev;
62 	struct watchdog_device *wdt;
63 
64 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
65 	if (!wdt)
66 		return -ENOMEM;
67 
68 	wdt->info		= &twl4030_wdt_info;
69 	wdt->ops		= &twl4030_wdt_ops;
70 	wdt->status		= 0;
71 	wdt->timeout		= 30;
72 	wdt->min_timeout	= 1;
73 	wdt->max_timeout	= 30;
74 	wdt->parent = dev;
75 
76 	watchdog_set_nowayout(wdt, nowayout);
77 	platform_set_drvdata(pdev, wdt);
78 
79 	twl4030_wdt_stop(wdt);
80 
81 	return devm_watchdog_register_device(dev, wdt);
82 }
83 
84 #ifdef CONFIG_PM
85 static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
86 {
87 	struct watchdog_device *wdt = platform_get_drvdata(pdev);
88 	if (watchdog_active(wdt))
89 		return twl4030_wdt_stop(wdt);
90 
91 	return 0;
92 }
93 
94 static int twl4030_wdt_resume(struct platform_device *pdev)
95 {
96 	struct watchdog_device *wdt = platform_get_drvdata(pdev);
97 	if (watchdog_active(wdt))
98 		return twl4030_wdt_start(wdt);
99 
100 	return 0;
101 }
102 #else
103 #define twl4030_wdt_suspend        NULL
104 #define twl4030_wdt_resume         NULL
105 #endif
106 
107 static const struct of_device_id twl_wdt_of_match[] = {
108 	{ .compatible = "ti,twl4030-wdt", },
109 	{ },
110 };
111 MODULE_DEVICE_TABLE(of, twl_wdt_of_match);
112 
113 static struct platform_driver twl4030_wdt_driver = {
114 	.probe		= twl4030_wdt_probe,
115 	.suspend	= twl4030_wdt_suspend,
116 	.resume		= twl4030_wdt_resume,
117 	.driver		= {
118 		.name		= "twl4030_wdt",
119 		.of_match_table	= twl_wdt_of_match,
120 	},
121 };
122 
123 module_platform_driver(twl4030_wdt_driver);
124 
125 MODULE_AUTHOR("Nokia Corporation");
126 MODULE_LICENSE("GPL");
127 MODULE_ALIAS("platform:twl4030_wdt");
128 
129