1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Watchdog driver for Ricoh RN5T618 PMIC
4  *
5  * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
6  */
7 
8 #include <linux/device.h>
9 #include <linux/mfd/rn5t618.h>
10 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/watchdog.h>
13 
14 #define DRIVER_NAME "rn5t618-wdt"
15 
16 static bool nowayout = WATCHDOG_NOWAYOUT;
17 static unsigned int timeout;
18 
19 module_param(timeout, uint, 0);
20 MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds");
21 
22 module_param(nowayout, bool, 0);
23 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
24 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
25 
26 struct rn5t618_wdt {
27 	struct watchdog_device wdt_dev;
28 	struct rn5t618 *rn5t618;
29 };
30 
31 /*
32  * This array encodes the values of WDOGTIM field for the supported
33  * watchdog expiration times. If the watchdog is not accessed before
34  * the timer expiration, the PMU generates an interrupt and if the CPU
35  * doesn't clear it within one second the system is restarted.
36  */
37 static const struct {
38 	u8 reg_val;
39 	unsigned int time;
40 } rn5t618_wdt_map[] = {
41 	{ 0, 1 },
42 	{ 1, 8 },
43 	{ 2, 32 },
44 	{ 3, 128 },
45 };
46 
47 static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
48 				   unsigned int t)
49 {
50 	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
51 	int ret, i;
52 
53 	for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
54 		if (rn5t618_wdt_map[i].time + 1 >= t)
55 			break;
56 	}
57 
58 	if (i == ARRAY_SIZE(rn5t618_wdt_map))
59 		return -EINVAL;
60 
61 	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
62 				 RN5T618_WATCHDOG_WDOGTIM_M,
63 				 rn5t618_wdt_map[i].reg_val);
64 	if (!ret)
65 		wdt_dev->timeout = rn5t618_wdt_map[i].time;
66 
67 	return ret;
68 }
69 
70 static int rn5t618_wdt_start(struct watchdog_device *wdt_dev)
71 {
72 	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
73 	int ret;
74 
75 	ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
76 	if (ret)
77 		return ret;
78 
79 	/* enable repower-on */
80 	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT,
81 				 RN5T618_REPCNT_REPWRON,
82 				 RN5T618_REPCNT_REPWRON);
83 	if (ret)
84 		return ret;
85 
86 	/* enable watchdog */
87 	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
88 				 RN5T618_WATCHDOG_WDOGEN,
89 				 RN5T618_WATCHDOG_WDOGEN);
90 	if (ret)
91 		return ret;
92 
93 	/* enable watchdog interrupt */
94 	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN,
95 				  RN5T618_PWRIRQ_IR_WDOG,
96 				  RN5T618_PWRIRQ_IR_WDOG);
97 }
98 
99 static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev)
100 {
101 	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
102 
103 	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
104 				  RN5T618_WATCHDOG_WDOGEN, 0);
105 }
106 
107 static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev)
108 {
109 	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
110 	unsigned int val;
111 	int ret;
112 
113 	/* The counter is restarted after a R/W access to watchdog register */
114 	ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val);
115 	if (ret)
116 		return ret;
117 
118 	ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val);
119 	if (ret)
120 		return ret;
121 
122 	/* Clear pending watchdog interrupt */
123 	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ,
124 				  RN5T618_PWRIRQ_IR_WDOG, 0);
125 }
126 
127 static const struct watchdog_info rn5t618_wdt_info = {
128 	.options	= WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
129 			  WDIOF_KEEPALIVEPING,
130 	.identity	= DRIVER_NAME,
131 };
132 
133 static const struct watchdog_ops rn5t618_wdt_ops = {
134 	.owner          = THIS_MODULE,
135 	.start          = rn5t618_wdt_start,
136 	.stop           = rn5t618_wdt_stop,
137 	.ping           = rn5t618_wdt_ping,
138 	.set_timeout    = rn5t618_wdt_set_timeout,
139 };
140 
141 static int rn5t618_wdt_probe(struct platform_device *pdev)
142 {
143 	struct device *dev = &pdev->dev;
144 	struct rn5t618 *rn5t618 = dev_get_drvdata(dev->parent);
145 	struct rn5t618_wdt *wdt;
146 	int min_timeout, max_timeout;
147 
148 	wdt = devm_kzalloc(dev, sizeof(struct rn5t618_wdt), GFP_KERNEL);
149 	if (!wdt)
150 		return -ENOMEM;
151 
152 	min_timeout = rn5t618_wdt_map[0].time;
153 	max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time;
154 
155 	wdt->rn5t618 = rn5t618;
156 	wdt->wdt_dev.info = &rn5t618_wdt_info;
157 	wdt->wdt_dev.ops = &rn5t618_wdt_ops;
158 	wdt->wdt_dev.min_timeout = min_timeout;
159 	wdt->wdt_dev.max_timeout = max_timeout;
160 	wdt->wdt_dev.timeout = max_timeout;
161 	wdt->wdt_dev.parent = dev;
162 
163 	watchdog_set_drvdata(&wdt->wdt_dev, wdt);
164 	watchdog_init_timeout(&wdt->wdt_dev, timeout, dev);
165 	watchdog_set_nowayout(&wdt->wdt_dev, nowayout);
166 
167 	platform_set_drvdata(pdev, wdt);
168 
169 	return watchdog_register_device(&wdt->wdt_dev);
170 }
171 
172 static int rn5t618_wdt_remove(struct platform_device *pdev)
173 {
174 	struct rn5t618_wdt *wdt = platform_get_drvdata(pdev);
175 
176 	watchdog_unregister_device(&wdt->wdt_dev);
177 
178 	return 0;
179 }
180 
181 static struct platform_driver rn5t618_wdt_driver = {
182 	.probe = rn5t618_wdt_probe,
183 	.remove = rn5t618_wdt_remove,
184 	.driver = {
185 		.name	= DRIVER_NAME,
186 	},
187 };
188 
189 module_platform_driver(rn5t618_wdt_driver);
190 
191 MODULE_ALIAS("platform:rn5t618-wdt");
192 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
193 MODULE_DESCRIPTION("RN5T618 watchdog driver");
194 MODULE_LICENSE("GPL v2");
195