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