GNU Linux-libre 4.19.314-gnu1
[releases.git] / drivers / watchdog / da9052_wdt.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * System monitoring driver for DA9052 PMICs.
4  *
5  * Copyright(c) 2012 Dialog Semiconductor Ltd.
6  *
7  * Author: Anthony Olech <Anthony.Olech@diasemi.com>
8  *
9  */
10
11 #include <linux/module.h>
12 #include <linux/delay.h>
13 #include <linux/uaccess.h>
14 #include <linux/platform_device.h>
15 #include <linux/time.h>
16 #include <linux/watchdog.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/jiffies.h>
20
21 #include <linux/mfd/da9052/reg.h>
22 #include <linux/mfd/da9052/da9052.h>
23
24 #define DA9052_DEF_TIMEOUT      4
25 #define DA9052_TWDMIN           256
26
27 struct da9052_wdt_data {
28         struct watchdog_device wdt;
29         struct da9052 *da9052;
30         unsigned long jpast;
31 };
32
33 static const struct {
34         u8 reg_val;
35         int time;  /* Seconds */
36 } da9052_wdt_maps[] = {
37         { 1, 2 },
38         { 2, 4 },
39         { 3, 8 },
40         { 4, 16 },
41         { 5, 32 },
42         { 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
43         { 6, 65 },
44         { 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
45         { 7, 131 },
46 };
47
48
49 static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
50                                   unsigned int timeout)
51 {
52         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
53         struct da9052 *da9052 = driver_data->da9052;
54         int ret, i;
55
56         /*
57          * Disable the Watchdog timer before setting
58          * new time out.
59          */
60         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
61                                 DA9052_CONTROLD_TWDSCALE, 0);
62         if (ret < 0) {
63                 dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
64                         ret);
65                 return ret;
66         }
67         if (timeout) {
68                 /*
69                  * To change the timeout, da9052 needs to
70                  * be disabled for at least 150 us.
71                  */
72                 udelay(150);
73
74                 /* Set the desired timeout */
75                 for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
76                         if (da9052_wdt_maps[i].time == timeout)
77                                 break;
78
79                 if (i == ARRAY_SIZE(da9052_wdt_maps))
80                         ret = -EINVAL;
81                 else
82                         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
83                                                 DA9052_CONTROLD_TWDSCALE,
84                                                 da9052_wdt_maps[i].reg_val);
85                 if (ret < 0) {
86                         dev_err(da9052->dev,
87                                 "Failed to update timescale bit, %d\n", ret);
88                         return ret;
89                 }
90
91                 wdt_dev->timeout = timeout;
92                 driver_data->jpast = jiffies;
93         }
94
95         return 0;
96 }
97
98 static int da9052_wdt_start(struct watchdog_device *wdt_dev)
99 {
100         return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
101 }
102
103 static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
104 {
105         return da9052_wdt_set_timeout(wdt_dev, 0);
106 }
107
108 static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
109 {
110         struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
111         struct da9052 *da9052 = driver_data->da9052;
112         unsigned long msec, jnow = jiffies;
113         int ret;
114
115         /*
116          * We have a minimum time for watchdog window called TWDMIN. A write
117          * to the watchdog before this elapsed time should cause an error.
118          */
119         msec = (jnow - driver_data->jpast) * 1000/HZ;
120         if (msec < DA9052_TWDMIN)
121                 mdelay(msec);
122
123         /* Reset the watchdog timer */
124         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
125                                 DA9052_CONTROLD_WATCHDOG, 1 << 7);
126         if (ret < 0)
127                 return ret;
128
129         /*
130          * FIXME: Reset the watchdog core, in general PMIC
131          * is supposed to do this
132          */
133         return da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
134                                  DA9052_CONTROLD_WATCHDOG, 0 << 7);
135 }
136
137 static const struct watchdog_info da9052_wdt_info = {
138         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
139         .identity       = "DA9052 Watchdog",
140 };
141
142 static const struct watchdog_ops da9052_wdt_ops = {
143         .owner = THIS_MODULE,
144         .start = da9052_wdt_start,
145         .stop = da9052_wdt_stop,
146         .ping = da9052_wdt_ping,
147         .set_timeout = da9052_wdt_set_timeout,
148 };
149
150
151 static int da9052_wdt_probe(struct platform_device *pdev)
152 {
153         struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent);
154         struct da9052_wdt_data *driver_data;
155         struct watchdog_device *da9052_wdt;
156         int ret;
157
158         driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
159                                    GFP_KERNEL);
160         if (!driver_data)
161                 return -ENOMEM;
162         driver_data->da9052 = da9052;
163
164         da9052_wdt = &driver_data->wdt;
165
166         da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
167         da9052_wdt->info = &da9052_wdt_info;
168         da9052_wdt->ops = &da9052_wdt_ops;
169         da9052_wdt->parent = &pdev->dev;
170         watchdog_set_drvdata(da9052_wdt, driver_data);
171
172         ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
173                                 DA9052_CONTROLD_TWDSCALE, 0);
174         if (ret < 0) {
175                 dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n",
176                         ret);
177                 return ret;
178         }
179
180         ret = devm_watchdog_register_device(&pdev->dev, &driver_data->wdt);
181         if (ret != 0) {
182                 dev_err(da9052->dev, "watchdog_register_device() failed: %d\n",
183                         ret);
184                 return ret;
185         }
186
187         return ret;
188 }
189
190 static struct platform_driver da9052_wdt_driver = {
191         .probe = da9052_wdt_probe,
192         .driver = {
193                 .name   = "da9052-watchdog",
194         },
195 };
196
197 module_platform_driver(da9052_wdt_driver);
198
199 MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
200 MODULE_DESCRIPTION("DA9052 SM Device Driver");
201 MODULE_LICENSE("GPL");
202 MODULE_ALIAS("platform:da9052-watchdog");