1/*
2 * Watchdog driver for DA9063 PMICs.
3 *
4 * Copyright(c) 2012 Dialog Semiconductor Ltd.
5 *
6 * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
7 *
8 * This program is free software; you can redistribute  it and/or modify it
9 * under  the terms of  the GNU General  Public License as published by the
10 * Free Software Foundation;  either version 2 of the  License, or (at your
11 * option) any later version.
12 */
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/watchdog.h>
17#include <linux/platform_device.h>
18#include <linux/uaccess.h>
19#include <linux/slab.h>
20#include <linux/delay.h>
21#include <linux/mfd/da9063/registers.h>
22#include <linux/mfd/da9063/core.h>
23#include <linux/reboot.h>
24#include <linux/regmap.h>
25
26/*
27 * Watchdog selector to timeout in seconds.
28 *   0: WDT disabled;
29 *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
30 */
31static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
32#define DA9063_TWDSCALE_DISABLE		0
33#define DA9063_TWDSCALE_MIN		1
34#define DA9063_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
35#define DA9063_WDT_MIN_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MIN]
36#define DA9063_WDT_MAX_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MAX]
37#define DA9063_WDG_TIMEOUT		wdt_timeout[3]
38
39struct da9063_watchdog {
40	struct da9063 *da9063;
41	struct watchdog_device wdtdev;
42	struct notifier_block restart_handler;
43};
44
45static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
46{
47	unsigned int i;
48
49	for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
50		if (wdt_timeout[i] >= secs)
51			return i;
52	}
53
54	return DA9063_TWDSCALE_MAX;
55}
56
57static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
58{
59	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
60				  DA9063_TWDSCALE_MASK, regval);
61}
62
63static int da9063_wdt_start(struct watchdog_device *wdd)
64{
65	struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
66	unsigned int selector;
67	int ret;
68
69	selector = da9063_wdt_timeout_to_sel(wdt->wdtdev.timeout);
70	ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
71	if (ret)
72		dev_err(wdt->da9063->dev, "Watchdog failed to start (err = %d)\n",
73			ret);
74
75	return ret;
76}
77
78static int da9063_wdt_stop(struct watchdog_device *wdd)
79{
80	struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
81	int ret;
82
83	ret = regmap_update_bits(wdt->da9063->regmap, DA9063_REG_CONTROL_D,
84				 DA9063_TWDSCALE_MASK, DA9063_TWDSCALE_DISABLE);
85	if (ret)
86		dev_alert(wdt->da9063->dev, "Watchdog failed to stop (err = %d)\n",
87			  ret);
88
89	return ret;
90}
91
92static int da9063_wdt_ping(struct watchdog_device *wdd)
93{
94	struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
95	int ret;
96
97	ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
98			   DA9063_WATCHDOG);
99	if (ret)
100		dev_alert(wdt->da9063->dev, "Failed to ping the watchdog (err = %d)\n",
101			  ret);
102
103	return ret;
104}
105
106static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
107				  unsigned int timeout)
108{
109	struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
110	unsigned int selector;
111	int ret;
112
113	selector = da9063_wdt_timeout_to_sel(timeout);
114	ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
115	if (ret)
116		dev_err(wdt->da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
117			ret);
118	else
119		wdd->timeout = wdt_timeout[selector];
120
121	return ret;
122}
123
124static int da9063_wdt_restart_handler(struct notifier_block *this,
125				      unsigned long mode, void *cmd)
126{
127	struct da9063_watchdog *wdt = container_of(this,
128						   struct da9063_watchdog,
129						   restart_handler);
130	int ret;
131
132	ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
133			   DA9063_SHUTDOWN);
134	if (ret)
135		dev_alert(wdt->da9063->dev, "Failed to shutdown (err = %d)\n",
136			  ret);
137
138	return NOTIFY_DONE;
139}
140
141static const struct watchdog_info da9063_watchdog_info = {
142	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
143	.identity = "DA9063 Watchdog",
144};
145
146static const struct watchdog_ops da9063_watchdog_ops = {
147	.owner = THIS_MODULE,
148	.start = da9063_wdt_start,
149	.stop = da9063_wdt_stop,
150	.ping = da9063_wdt_ping,
151	.set_timeout = da9063_wdt_set_timeout,
152};
153
154static int da9063_wdt_probe(struct platform_device *pdev)
155{
156	int ret;
157	struct da9063 *da9063;
158	struct da9063_watchdog *wdt;
159
160	if (!pdev->dev.parent)
161		return -EINVAL;
162
163	da9063 = dev_get_drvdata(pdev->dev.parent);
164	if (!da9063)
165		return -EINVAL;
166
167	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
168	if (!wdt)
169		return -ENOMEM;
170
171	wdt->da9063 = da9063;
172
173	wdt->wdtdev.info = &da9063_watchdog_info;
174	wdt->wdtdev.ops = &da9063_watchdog_ops;
175	wdt->wdtdev.min_timeout = DA9063_WDT_MIN_TIMEOUT;
176	wdt->wdtdev.max_timeout = DA9063_WDT_MAX_TIMEOUT;
177	wdt->wdtdev.timeout = DA9063_WDG_TIMEOUT;
178
179	wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
180
181	watchdog_set_drvdata(&wdt->wdtdev, wdt);
182	dev_set_drvdata(&pdev->dev, wdt);
183
184	ret = watchdog_register_device(&wdt->wdtdev);
185	if (ret)
186		return ret;
187
188	wdt->restart_handler.notifier_call = da9063_wdt_restart_handler;
189	wdt->restart_handler.priority = 128;
190	ret = register_restart_handler(&wdt->restart_handler);
191	if (ret)
192		dev_err(wdt->da9063->dev,
193			"Failed to register restart handler (err = %d)\n", ret);
194
195	return 0;
196}
197
198static int da9063_wdt_remove(struct platform_device *pdev)
199{
200	struct da9063_watchdog *wdt = dev_get_drvdata(&pdev->dev);
201
202	unregister_restart_handler(&wdt->restart_handler);
203
204	watchdog_unregister_device(&wdt->wdtdev);
205
206	return 0;
207}
208
209static struct platform_driver da9063_wdt_driver = {
210	.probe = da9063_wdt_probe,
211	.remove = da9063_wdt_remove,
212	.driver = {
213		.name = DA9063_DRVNAME_WATCHDOG,
214	},
215};
216module_platform_driver(da9063_wdt_driver);
217
218MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
219MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
220MODULE_LICENSE("GPL");
221MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
222