Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[firefly-linux-kernel-4.4.55.git] / drivers / watchdog / rn5t618_wdt.c
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");