1 /*
2 * Maxim MAX77620 Watchdog Driver
3 *
4 * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
5 *
6 * Author: Laxman Dewangan <ldewangan@nvidia.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/err.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/mod_devicetable.h>
18 #include <linux/mfd/max77620.h>
19 #include <linux/platform_device.h>
20 #include <linux/regmap.h>
21 #include <linux/slab.h>
22 #include <linux/watchdog.h>
23
24 static bool nowayout = WATCHDOG_NOWAYOUT;
25
26 struct max77620_wdt {
27 struct device *dev;
28 struct regmap *rmap;
29 struct watchdog_device wdt_dev;
30 };
31
max77620_wdt_start(struct watchdog_device * wdt_dev)32 static int max77620_wdt_start(struct watchdog_device *wdt_dev)
33 {
34 struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
35
36 return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
37 MAX77620_WDTEN, MAX77620_WDTEN);
38 }
39
max77620_wdt_stop(struct watchdog_device * wdt_dev)40 static int max77620_wdt_stop(struct watchdog_device *wdt_dev)
41 {
42 struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
43
44 return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
45 MAX77620_WDTEN, 0);
46 }
47
max77620_wdt_ping(struct watchdog_device * wdt_dev)48 static int max77620_wdt_ping(struct watchdog_device *wdt_dev)
49 {
50 struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
51
52 return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3,
53 MAX77620_WDTC_MASK, 0x1);
54 }
55
max77620_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)56 static int max77620_wdt_set_timeout(struct watchdog_device *wdt_dev,
57 unsigned int timeout)
58 {
59 struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
60 unsigned int wdt_timeout;
61 u8 regval;
62 int ret;
63
64 switch (timeout) {
65 case 0 ... 2:
66 regval = MAX77620_TWD_2s;
67 wdt_timeout = 2;
68 break;
69
70 case 3 ... 16:
71 regval = MAX77620_TWD_16s;
72 wdt_timeout = 16;
73 break;
74
75 case 17 ... 64:
76 regval = MAX77620_TWD_64s;
77 wdt_timeout = 64;
78 break;
79
80 default:
81 regval = MAX77620_TWD_128s;
82 wdt_timeout = 128;
83 break;
84 }
85
86 ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3,
87 MAX77620_WDTC_MASK, 0x1);
88 if (ret < 0)
89 return ret;
90
91 ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
92 MAX77620_TWD_MASK, regval);
93 if (ret < 0)
94 return ret;
95
96 wdt_dev->timeout = wdt_timeout;
97
98 return 0;
99 }
100
101 static const struct watchdog_info max77620_wdt_info = {
102 .identity = "max77620-watchdog",
103 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
104 };
105
106 static const struct watchdog_ops max77620_wdt_ops = {
107 .start = max77620_wdt_start,
108 .stop = max77620_wdt_stop,
109 .ping = max77620_wdt_ping,
110 .set_timeout = max77620_wdt_set_timeout,
111 };
112
max77620_wdt_probe(struct platform_device * pdev)113 static int max77620_wdt_probe(struct platform_device *pdev)
114 {
115 struct max77620_wdt *wdt;
116 struct watchdog_device *wdt_dev;
117 unsigned int regval;
118 int ret;
119
120 wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
121 if (!wdt)
122 return -ENOMEM;
123
124 wdt->dev = &pdev->dev;
125 wdt->rmap = dev_get_regmap(pdev->dev.parent, NULL);
126 if (!wdt->rmap) {
127 dev_err(wdt->dev, "Failed to get parent regmap\n");
128 return -ENODEV;
129 }
130
131 wdt_dev = &wdt->wdt_dev;
132 wdt_dev->info = &max77620_wdt_info;
133 wdt_dev->ops = &max77620_wdt_ops;
134 wdt_dev->min_timeout = 2;
135 wdt_dev->max_timeout = 128;
136 wdt_dev->max_hw_heartbeat_ms = 128 * 1000;
137
138 platform_set_drvdata(pdev, wdt);
139
140 /* Enable WD_RST_WK - WDT expire results in a restart */
141 ret = regmap_update_bits(wdt->rmap, MAX77620_REG_ONOFFCNFG2,
142 MAX77620_ONOFFCNFG2_WD_RST_WK,
143 MAX77620_ONOFFCNFG2_WD_RST_WK);
144 if (ret < 0) {
145 dev_err(wdt->dev, "Failed to set WD_RST_WK: %d\n", ret);
146 return ret;
147 }
148
149 /* Set WDT clear in OFF and sleep mode */
150 ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
151 MAX77620_WDTOFFC | MAX77620_WDTSLPC,
152 MAX77620_WDTOFFC | MAX77620_WDTSLPC);
153 if (ret < 0) {
154 dev_err(wdt->dev, "Failed to set WDT OFF mode: %d\n", ret);
155 return ret;
156 }
157
158 /* Check if WDT running and if yes then set flags properly */
159 ret = regmap_read(wdt->rmap, MAX77620_REG_CNFGGLBL2, ®val);
160 if (ret < 0) {
161 dev_err(wdt->dev, "Failed to read WDT CFG register: %d\n", ret);
162 return ret;
163 }
164
165 switch (regval & MAX77620_TWD_MASK) {
166 case MAX77620_TWD_2s:
167 wdt_dev->timeout = 2;
168 break;
169 case MAX77620_TWD_16s:
170 wdt_dev->timeout = 16;
171 break;
172 case MAX77620_TWD_64s:
173 wdt_dev->timeout = 64;
174 break;
175 default:
176 wdt_dev->timeout = 128;
177 break;
178 }
179
180 if (regval & MAX77620_WDTEN)
181 set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
182
183 watchdog_set_nowayout(wdt_dev, nowayout);
184 watchdog_set_drvdata(wdt_dev, wdt);
185
186 ret = watchdog_register_device(wdt_dev);
187 if (ret < 0) {
188 dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret);
189 return ret;
190 }
191
192 return 0;
193 }
194
max77620_wdt_remove(struct platform_device * pdev)195 static int max77620_wdt_remove(struct platform_device *pdev)
196 {
197 struct max77620_wdt *wdt = platform_get_drvdata(pdev);
198
199 max77620_wdt_stop(&wdt->wdt_dev);
200 watchdog_unregister_device(&wdt->wdt_dev);
201
202 return 0;
203 }
204
205 static const struct platform_device_id max77620_wdt_devtype[] = {
206 { .name = "max77620-watchdog", },
207 { },
208 };
209 MODULE_DEVICE_TABLE(platform, max77620_wdt_devtype);
210
211 static struct platform_driver max77620_wdt_driver = {
212 .driver = {
213 .name = "max77620-watchdog",
214 },
215 .probe = max77620_wdt_probe,
216 .remove = max77620_wdt_remove,
217 .id_table = max77620_wdt_devtype,
218 };
219
220 module_platform_driver(max77620_wdt_driver);
221
222 MODULE_DESCRIPTION("Max77620 watchdog timer driver");
223
224 module_param(nowayout, bool, 0);
225 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
226 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
227
228 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
229 MODULE_LICENSE("GPL v2");
230
