xref: /openbmc/linux/drivers/watchdog/da9052_wdt.c (revision 60415f70)
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