virtio-mem: simplify high-level unplug handling in Sub Block Mode
[linux-2.6-microblaze.git] / drivers / watchdog / da9055_wdt.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * System monitoring driver for DA9055 PMICs.
4  *
5  * Copyright(c) 2012 Dialog Semiconductor Ltd.
6  *
7  * Author: David Dajun Chen <dchen@diasemi.com>
8  *
9  */
10
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/platform_device.h>
16 #include <linux/watchdog.h>
17 #include <linux/delay.h>
18
19 #include <linux/mfd/da9055/core.h>
20 #include <linux/mfd/da9055/reg.h>
21
22 static bool nowayout = WATCHDOG_NOWAYOUT;
23 module_param(nowayout, bool, 0);
24 MODULE_PARM_DESC(nowayout,
25                  "Watchdog cannot be stopped once started (default="
26                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
27
28 #define DA9055_DEF_TIMEOUT      4
29 #define DA9055_TWDMIN           256
30
31 struct da9055_wdt_data {
32         struct watchdog_device wdt;
33         struct da9055 *da9055;
34 };
35
36 static const struct {
37         u8 reg_val;
38         int user_time;  /* In seconds */
39 } da9055_wdt_maps[] = {
40         { 0, 0 },
41         { 1, 2 },
42         { 2, 4 },
43         { 3, 8 },
44         { 4, 16 },
45         { 5, 32 },
46         { 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
47         { 6, 65 },
48         { 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
49         { 7, 131 },
50 };
51
52 static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
53                                   unsigned int timeout)
54 {
55         struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
56         struct da9055 *da9055 = driver_data->da9055;
57         int ret, i;
58
59         for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
60                 if (da9055_wdt_maps[i].user_time == timeout)
61                         break;
62
63         if (i == ARRAY_SIZE(da9055_wdt_maps))
64                 ret = -EINVAL;
65         else
66                 ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
67                                         DA9055_TWDSCALE_MASK,
68                                         da9055_wdt_maps[i].reg_val <<
69                                         DA9055_TWDSCALE_SHIFT);
70         if (ret < 0) {
71                 dev_err(da9055->dev,
72                         "Failed to update timescale bit, %d\n", ret);
73                 return ret;
74         }
75
76         wdt_dev->timeout = timeout;
77
78         return 0;
79 }
80
81 static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
82 {
83         struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
84         struct da9055 *da9055 = driver_data->da9055;
85
86         /*
87          * We have a minimum time for watchdog window called TWDMIN. A write
88          * to the watchdog before this elapsed time will cause an error.
89          */
90         mdelay(DA9055_TWDMIN);
91
92         /* Reset the watchdog timer */
93         return da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
94                                  DA9055_WATCHDOG_MASK, 1);
95 }
96
97 static int da9055_wdt_start(struct watchdog_device *wdt_dev)
98 {
99         return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
100 }
101
102 static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
103 {
104         return da9055_wdt_set_timeout(wdt_dev, 0);
105 }
106
107 static const struct watchdog_info da9055_wdt_info = {
108         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
109         .identity       = "DA9055 Watchdog",
110 };
111
112 static const struct watchdog_ops da9055_wdt_ops = {
113         .owner = THIS_MODULE,
114         .start = da9055_wdt_start,
115         .stop = da9055_wdt_stop,
116         .ping = da9055_wdt_ping,
117         .set_timeout = da9055_wdt_set_timeout,
118 };
119
120 static int da9055_wdt_probe(struct platform_device *pdev)
121 {
122         struct device *dev = &pdev->dev;
123         struct da9055 *da9055 = dev_get_drvdata(dev->parent);
124         struct da9055_wdt_data *driver_data;
125         struct watchdog_device *da9055_wdt;
126         int ret;
127
128         driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
129         if (!driver_data)
130                 return -ENOMEM;
131
132         driver_data->da9055 = da9055;
133
134         da9055_wdt = &driver_data->wdt;
135
136         da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
137         da9055_wdt->info = &da9055_wdt_info;
138         da9055_wdt->ops = &da9055_wdt_ops;
139         da9055_wdt->parent = dev;
140         watchdog_set_nowayout(da9055_wdt, nowayout);
141         watchdog_set_drvdata(da9055_wdt, driver_data);
142
143         ret = da9055_wdt_stop(da9055_wdt);
144         if (ret < 0) {
145                 dev_err(dev, "Failed to stop watchdog, %d\n", ret);
146                 return ret;
147         }
148
149         ret = devm_watchdog_register_device(dev, &driver_data->wdt);
150         if (ret != 0)
151                 dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
152                         ret);
153
154         return ret;
155 }
156
157 static struct platform_driver da9055_wdt_driver = {
158         .probe = da9055_wdt_probe,
159         .driver = {
160                 .name   = "da9055-watchdog",
161         },
162 };
163
164 module_platform_driver(da9055_wdt_driver);
165
166 MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
167 MODULE_DESCRIPTION("DA9055 watchdog");
168 MODULE_LICENSE("GPL");
169 MODULE_ALIAS("platform:da9055-watchdog");