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
27struct da9052_wdt_data {
28	struct watchdog_device wdt;
29	struct da9052 *da9052;
30	unsigned long jpast;
31};
32
33static 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
49static 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
98static int da9052_wdt_start(struct watchdog_device *wdt_dev)
99{
100	return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
101}
102
103static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
104{
105	return da9052_wdt_set_timeout(wdt_dev, 0);
106}
107
108static 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
137static const struct watchdog_info da9052_wdt_info = {
138	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
139	.identity	= "DA9052 Watchdog",
140};
141
142static 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
151static 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
182static struct platform_driver da9052_wdt_driver = {
183	.probe = da9052_wdt_probe,
184	.driver = {
185		.name	= "da9052-watchdog",
186	},
187};
188
189module_platform_driver(da9052_wdt_driver);
190
191MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
192MODULE_DESCRIPTION("DA9052 SM Device Driver");
193MODULE_LICENSE("GPL");
194MODULE_ALIAS("platform:da9052-watchdog");
195