1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Watchdog driver for Ricoh RN5T618 PMIC
4 *
5 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
6 */
7
8#include <linux/device.h>
9#include <linux/mfd/rn5t618.h>
10#include <linux/module.h>
11#include <linux/platform_device.h>
12#include <linux/watchdog.h>
13
14#define DRIVER_NAME "rn5t618-wdt"
15
16static bool nowayout = WATCHDOG_NOWAYOUT;
17static unsigned int timeout;
18
19module_param(timeout, uint, 0);
20MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds");
21
22module_param(nowayout, bool, 0);
23MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
24		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
25
26struct rn5t618_wdt {
27	struct watchdog_device wdt_dev;
28	struct rn5t618 *rn5t618;
29};
30
31/*
32 * This array encodes the values of WDOGTIM field for the supported
33 * watchdog expiration times. If the watchdog is not accessed before
34 * the timer expiration, the PMU generates an interrupt and if the CPU
35 * doesn't clear it within one second the system is restarted.
36 */
37static const struct {
38	u8 reg_val;
39	unsigned int time;
40} rn5t618_wdt_map[] = {
41	{ 0, 1 },
42	{ 1, 8 },
43	{ 2, 32 },
44	{ 3, 128 },
45};
46
47static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
48				   unsigned int t)
49{
50	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
51	int ret, i;
52
53	for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
54		if (rn5t618_wdt_map[i].time + 1 >= t)
55			break;
56	}
57
58	if (i == ARRAY_SIZE(rn5t618_wdt_map))
59		return -EINVAL;
60
61	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
62				 RN5T618_WATCHDOG_WDOGTIM_M,
63				 rn5t618_wdt_map[i].reg_val);
64	if (!ret)
65		wdt_dev->timeout = rn5t618_wdt_map[i].time;
66
67	return ret;
68}
69
70static int rn5t618_wdt_start(struct watchdog_device *wdt_dev)
71{
72	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
73	int ret;
74
75	ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
76	if (ret)
77		return ret;
78
79	/* enable repower-on */
80	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT,
81				 RN5T618_REPCNT_REPWRON,
82				 RN5T618_REPCNT_REPWRON);
83	if (ret)
84		return ret;
85
86	/* enable watchdog */
87	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
88				 RN5T618_WATCHDOG_WDOGEN,
89				 RN5T618_WATCHDOG_WDOGEN);
90	if (ret)
91		return ret;
92
93	/* enable watchdog interrupt */
94	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN,
95				  RN5T618_PWRIRQ_IR_WDOG,
96				  RN5T618_PWRIRQ_IR_WDOG);
97}
98
99static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev)
100{
101	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
102
103	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
104				  RN5T618_WATCHDOG_WDOGEN, 0);
105}
106
107static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev)
108{
109	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
110	unsigned int val;
111	int ret;
112
113	/* The counter is restarted after a R/W access to watchdog register */
114	ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val);
115	if (ret)
116		return ret;
117
118	ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val);
119	if (ret)
120		return ret;
121
122	/* Clear pending watchdog interrupt */
123	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ,
124				  RN5T618_PWRIRQ_IR_WDOG, 0);
125}
126
127static const struct watchdog_info rn5t618_wdt_info = {
128	.options	= WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
129			  WDIOF_KEEPALIVEPING,
130	.identity	= DRIVER_NAME,
131};
132
133static const struct watchdog_ops rn5t618_wdt_ops = {
134	.owner          = THIS_MODULE,
135	.start          = rn5t618_wdt_start,
136	.stop           = rn5t618_wdt_stop,
137	.ping           = rn5t618_wdt_ping,
138	.set_timeout    = rn5t618_wdt_set_timeout,
139};
140
141static int rn5t618_wdt_probe(struct platform_device *pdev)
142{
143	struct device *dev = &pdev->dev;
144	struct rn5t618 *rn5t618 = dev_get_drvdata(dev->parent);
145	struct rn5t618_wdt *wdt;
146	int min_timeout, max_timeout;
147
148	wdt = devm_kzalloc(dev, sizeof(struct rn5t618_wdt), GFP_KERNEL);
149	if (!wdt)
150		return -ENOMEM;
151
152	min_timeout = rn5t618_wdt_map[0].time;
153	max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time;
154
155	wdt->rn5t618 = rn5t618;
156	wdt->wdt_dev.info = &rn5t618_wdt_info;
157	wdt->wdt_dev.ops = &rn5t618_wdt_ops;
158	wdt->wdt_dev.min_timeout = min_timeout;
159	wdt->wdt_dev.max_timeout = max_timeout;
160	wdt->wdt_dev.timeout = max_timeout;
161	wdt->wdt_dev.parent = dev;
162
163	watchdog_set_drvdata(&wdt->wdt_dev, wdt);
164	watchdog_init_timeout(&wdt->wdt_dev, timeout, dev);
165	watchdog_set_nowayout(&wdt->wdt_dev, nowayout);
166
167	platform_set_drvdata(pdev, wdt);
168
169	return watchdog_register_device(&wdt->wdt_dev);
170}
171
172static int rn5t618_wdt_remove(struct platform_device *pdev)
173{
174	struct rn5t618_wdt *wdt = platform_get_drvdata(pdev);
175
176	watchdog_unregister_device(&wdt->wdt_dev);
177
178	return 0;
179}
180
181static struct platform_driver rn5t618_wdt_driver = {
182	.probe = rn5t618_wdt_probe,
183	.remove = rn5t618_wdt_remove,
184	.driver = {
185		.name	= DRIVER_NAME,
186	},
187};
188
189module_platform_driver(rn5t618_wdt_driver);
190
191MODULE_ALIAS("platform:rn5t618-wdt");
192MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
193MODULE_DESCRIPTION("RN5T618 watchdog driver");
194MODULE_LICENSE("GPL v2");
195