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
da9052_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)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
da9052_wdt_start(struct watchdog_device * wdt_dev)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
da9052_wdt_stop(struct watchdog_device * wdt_dev)103 static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
104 {
105 return da9052_wdt_set_timeout(wdt_dev, 0);
106 }
107
da9052_wdt_ping(struct watchdog_device * wdt_dev)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
da9052_wdt_probe(struct platform_device * pdev)151 static int da9052_wdt_probe(struct platform_device *pdev)
152 {
153 struct device *dev = &pdev->dev;
154 struct da9052 *da9052 = dev_get_drvdata(dev->parent);
155 struct da9052_wdt_data *driver_data;
156 struct watchdog_device *da9052_wdt;
157 int ret;
158
159 driver_data = devm_kzalloc(dev, sizeof(*driver_data), 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 = 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(dev, "Failed to disable watchdog bits, %d\n", ret);
176 return ret;
177 }
178
179 return devm_watchdog_register_device(dev, &driver_data->wdt);
180 }
181
182 static struct platform_driver da9052_wdt_driver = {
183 .probe = da9052_wdt_probe,
184 .driver = {
185 .name = "da9052-watchdog",
186 },
187 };
188
189 module_platform_driver(da9052_wdt_driver);
190
191 MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
192 MODULE_DESCRIPTION("DA9052 SM Device Driver");
193 MODULE_LICENSE("GPL");
194 MODULE_ALIAS("platform:da9052-watchdog");
195