xref: /openbmc/linux/drivers/watchdog/da9063_wdt.c (revision c819e2cf)
1 /*
2  * Watchdog driver for DA9063 PMICs.
3  *
4  * Copyright(c) 2012 Dialog Semiconductor Ltd.
5  *
6  * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
7  *
8  * This program is free software; you can redistribute  it and/or modify it
9  * under  the terms of  the GNU General  Public License as published by the
10  * Free Software Foundation;  either version 2 of the  License, or (at your
11  * option) any later version.
12  */
13 
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/watchdog.h>
17 #include <linux/platform_device.h>
18 #include <linux/uaccess.h>
19 #include <linux/slab.h>
20 #include <linux/delay.h>
21 #include <linux/mfd/da9063/registers.h>
22 #include <linux/mfd/da9063/core.h>
23 #include <linux/regmap.h>
24 
25 /*
26  * Watchdog selector to timeout in seconds.
27  *   0: WDT disabled;
28  *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
29  */
30 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
31 #define DA9063_TWDSCALE_DISABLE		0
32 #define DA9063_TWDSCALE_MIN		1
33 #define DA9063_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
34 #define DA9063_WDT_MIN_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MIN]
35 #define DA9063_WDT_MAX_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MAX]
36 #define DA9063_WDG_TIMEOUT		wdt_timeout[3]
37 
38 struct da9063_watchdog {
39 	struct da9063 *da9063;
40 	struct watchdog_device wdtdev;
41 };
42 
43 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
44 {
45 	unsigned int i;
46 
47 	for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
48 		if (wdt_timeout[i] >= secs)
49 			return i;
50 	}
51 
52 	return DA9063_TWDSCALE_MAX;
53 }
54 
55 static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
56 {
57 	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
58 				  DA9063_TWDSCALE_MASK, regval);
59 }
60 
61 static int da9063_wdt_start(struct watchdog_device *wdd)
62 {
63 	struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
64 	unsigned int selector;
65 	int ret;
66 
67 	selector = da9063_wdt_timeout_to_sel(wdt->wdtdev.timeout);
68 	ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
69 	if (ret)
70 		dev_err(wdt->da9063->dev, "Watchdog failed to start (err = %d)\n",
71 			ret);
72 
73 	return ret;
74 }
75 
76 static int da9063_wdt_stop(struct watchdog_device *wdd)
77 {
78 	struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
79 	int ret;
80 
81 	ret = regmap_update_bits(wdt->da9063->regmap, DA9063_REG_CONTROL_D,
82 				 DA9063_TWDSCALE_MASK, DA9063_TWDSCALE_DISABLE);
83 	if (ret)
84 		dev_alert(wdt->da9063->dev, "Watchdog failed to stop (err = %d)\n",
85 			  ret);
86 
87 	return ret;
88 }
89 
90 static int da9063_wdt_ping(struct watchdog_device *wdd)
91 {
92 	struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
93 	int ret;
94 
95 	ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
96 			   DA9063_WATCHDOG);
97 	if (ret)
98 		dev_alert(wdt->da9063->dev, "Failed to ping the watchdog (err = %d)\n",
99 			  ret);
100 
101 	return ret;
102 }
103 
104 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
105 				  unsigned int timeout)
106 {
107 	struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
108 	unsigned int selector;
109 	int ret;
110 
111 	selector = da9063_wdt_timeout_to_sel(timeout);
112 	ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
113 	if (ret)
114 		dev_err(wdt->da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
115 			ret);
116 	else
117 		wdd->timeout = wdt_timeout[selector];
118 
119 	return ret;
120 }
121 
122 static const struct watchdog_info da9063_watchdog_info = {
123 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
124 	.identity = "DA9063 Watchdog",
125 };
126 
127 static const struct watchdog_ops da9063_watchdog_ops = {
128 	.owner = THIS_MODULE,
129 	.start = da9063_wdt_start,
130 	.stop = da9063_wdt_stop,
131 	.ping = da9063_wdt_ping,
132 	.set_timeout = da9063_wdt_set_timeout,
133 };
134 
135 static int da9063_wdt_probe(struct platform_device *pdev)
136 {
137 	int ret;
138 	struct da9063 *da9063;
139 	struct da9063_watchdog *wdt;
140 
141 	if (!pdev->dev.parent)
142 		return -EINVAL;
143 
144 	da9063 = dev_get_drvdata(pdev->dev.parent);
145 	if (!da9063)
146 		return -EINVAL;
147 
148 	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
149 	if (!wdt)
150 		return -ENOMEM;
151 
152 	wdt->da9063 = da9063;
153 
154 	wdt->wdtdev.info = &da9063_watchdog_info;
155 	wdt->wdtdev.ops = &da9063_watchdog_ops;
156 	wdt->wdtdev.min_timeout = DA9063_WDT_MIN_TIMEOUT;
157 	wdt->wdtdev.max_timeout = DA9063_WDT_MAX_TIMEOUT;
158 	wdt->wdtdev.timeout = DA9063_WDG_TIMEOUT;
159 
160 	wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
161 
162 	watchdog_set_drvdata(&wdt->wdtdev, wdt);
163 	dev_set_drvdata(&pdev->dev, wdt);
164 
165 	ret = watchdog_register_device(&wdt->wdtdev);
166 
167 	return ret;
168 }
169 
170 static int da9063_wdt_remove(struct platform_device *pdev)
171 {
172 	struct da9063_watchdog *wdt = dev_get_drvdata(&pdev->dev);
173 
174 	watchdog_unregister_device(&wdt->wdtdev);
175 
176 	return 0;
177 }
178 
179 static struct platform_driver da9063_wdt_driver = {
180 	.probe = da9063_wdt_probe,
181 	.remove = da9063_wdt_remove,
182 	.driver = {
183 		.name = DA9063_DRVNAME_WATCHDOG,
184 	},
185 };
186 module_platform_driver(da9063_wdt_driver);
187 
188 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
189 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
190 MODULE_LICENSE("GPL");
191 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
192