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22b1c841 BG |
1 | /* |
2 | * Watchdog driver for Ricoh RN5T618 PMIC | |
3 | * | |
4 | * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * version 2 as published by the Free Software Foundation. | |
9 | * | |
10 | * You should have received a copy of the GNU General Public License | |
11 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
12 | */ | |
13 | ||
14 | #include <linux/device.h> | |
15 | #include <linux/mfd/rn5t618.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/watchdog.h> | |
19 | ||
20 | #define DRIVER_NAME "rn5t618-wdt" | |
21 | ||
22 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
23 | static unsigned int timeout; | |
24 | ||
25 | module_param(timeout, uint, 0); | |
26 | MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds"); | |
27 | ||
28 | module_param(nowayout, bool, 0); | |
29 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
30 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
31 | ||
32 | struct rn5t618_wdt { | |
33 | struct watchdog_device wdt_dev; | |
34 | struct rn5t618 *rn5t618; | |
35 | }; | |
36 | ||
37 | /* | |
38 | * This array encodes the values of WDOGTIM field for the supported | |
39 | * watchdog expiration times. If the watchdog is not accessed before | |
40 | * the timer expiration, the PMU generates an interrupt and if the CPU | |
41 | * doesn't clear it within one second the system is restarted. | |
42 | */ | |
43 | static const struct { | |
44 | u8 reg_val; | |
45 | unsigned int time; | |
46 | } rn5t618_wdt_map[] = { | |
47 | { 0, 1 }, | |
48 | { 1, 8 }, | |
49 | { 2, 32 }, | |
50 | { 3, 128 }, | |
51 | }; | |
52 | ||
53 | static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
54 | unsigned int t) | |
55 | { | |
56 | struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); | |
57 | int ret, i; | |
58 | ||
59 | for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) { | |
60 | if (rn5t618_wdt_map[i].time + 1 >= t) | |
61 | break; | |
62 | } | |
63 | ||
64 | if (i == ARRAY_SIZE(rn5t618_wdt_map)) | |
65 | return -EINVAL; | |
66 | ||
67 | ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, | |
68 | RN5T618_WATCHDOG_WDOGTIM_M, | |
69 | rn5t618_wdt_map[i].reg_val); | |
70 | if (!ret) | |
71 | wdt_dev->timeout = rn5t618_wdt_map[i].time; | |
72 | ||
73 | return ret; | |
74 | } | |
75 | ||
76 | static int rn5t618_wdt_start(struct watchdog_device *wdt_dev) | |
77 | { | |
78 | struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); | |
79 | int ret; | |
80 | ||
81 | ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout); | |
82 | if (ret) | |
83 | return ret; | |
84 | ||
85 | /* enable repower-on */ | |
86 | ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT, | |
87 | RN5T618_REPCNT_REPWRON, | |
88 | RN5T618_REPCNT_REPWRON); | |
89 | if (ret) | |
90 | return ret; | |
91 | ||
92 | /* enable watchdog */ | |
93 | ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, | |
94 | RN5T618_WATCHDOG_WDOGEN, | |
95 | RN5T618_WATCHDOG_WDOGEN); | |
96 | if (ret) | |
97 | return ret; | |
98 | ||
99 | /* enable watchdog interrupt */ | |
100 | return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN, | |
101 | RN5T618_PWRIRQ_IR_WDOG, | |
102 | RN5T618_PWRIRQ_IR_WDOG); | |
103 | } | |
104 | ||
105 | static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev) | |
106 | { | |
107 | struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); | |
108 | ||
109 | return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, | |
110 | RN5T618_WATCHDOG_WDOGEN, 0); | |
111 | } | |
112 | ||
113 | static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev) | |
114 | { | |
115 | struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); | |
116 | unsigned int val; | |
117 | int ret; | |
118 | ||
119 | /* The counter is restarted after a R/W access to watchdog register */ | |
120 | ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val); | |
121 | if (ret) | |
122 | return ret; | |
123 | ||
124 | ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val); | |
125 | if (ret) | |
126 | return ret; | |
127 | ||
128 | /* Clear pending watchdog interrupt */ | |
129 | return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ, | |
130 | RN5T618_PWRIRQ_IR_WDOG, 0); | |
131 | } | |
132 | ||
133 | static struct watchdog_info rn5t618_wdt_info = { | |
134 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | | |
135 | WDIOF_KEEPALIVEPING, | |
136 | .identity = DRIVER_NAME, | |
137 | }; | |
138 | ||
139 | static struct watchdog_ops rn5t618_wdt_ops = { | |
140 | .owner = THIS_MODULE, | |
141 | .start = rn5t618_wdt_start, | |
142 | .stop = rn5t618_wdt_stop, | |
143 | .ping = rn5t618_wdt_ping, | |
144 | .set_timeout = rn5t618_wdt_set_timeout, | |
145 | }; | |
146 | ||
147 | static int rn5t618_wdt_probe(struct platform_device *pdev) | |
148 | { | |
149 | struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent); | |
150 | struct rn5t618_wdt *wdt; | |
151 | int min_timeout, max_timeout; | |
152 | ||
153 | wdt = devm_kzalloc(&pdev->dev, sizeof(struct rn5t618_wdt), GFP_KERNEL); | |
154 | if (!wdt) | |
155 | return -ENOMEM; | |
156 | ||
157 | min_timeout = rn5t618_wdt_map[0].time; | |
158 | max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time; | |
159 | ||
160 | wdt->rn5t618 = rn5t618; | |
161 | wdt->wdt_dev.info = &rn5t618_wdt_info; | |
162 | wdt->wdt_dev.ops = &rn5t618_wdt_ops; | |
163 | wdt->wdt_dev.min_timeout = min_timeout; | |
164 | wdt->wdt_dev.max_timeout = max_timeout; | |
165 | wdt->wdt_dev.timeout = max_timeout; | |
166 | wdt->wdt_dev.parent = &pdev->dev; | |
167 | ||
168 | watchdog_set_drvdata(&wdt->wdt_dev, wdt); | |
169 | watchdog_init_timeout(&wdt->wdt_dev, timeout, &pdev->dev); | |
170 | watchdog_set_nowayout(&wdt->wdt_dev, nowayout); | |
171 | ||
172 | platform_set_drvdata(pdev, wdt); | |
173 | ||
174 | return watchdog_register_device(&wdt->wdt_dev); | |
175 | } | |
176 | ||
177 | static int rn5t618_wdt_remove(struct platform_device *pdev) | |
178 | { | |
179 | struct rn5t618_wdt *wdt = platform_get_drvdata(pdev); | |
180 | ||
181 | watchdog_unregister_device(&wdt->wdt_dev); | |
182 | ||
183 | return 0; | |
184 | } | |
185 | ||
186 | static struct platform_driver rn5t618_wdt_driver = { | |
187 | .probe = rn5t618_wdt_probe, | |
188 | .remove = rn5t618_wdt_remove, | |
189 | .driver = { | |
190 | .name = DRIVER_NAME, | |
191 | }, | |
192 | }; | |
193 | ||
194 | module_platform_driver(rn5t618_wdt_driver); | |
195 | ||
196 | MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>"); | |
197 | MODULE_DESCRIPTION("RN5T618 watchdog driver"); | |
198 | MODULE_LICENSE("GPL v2"); |