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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 int ret;
148 unsigned int val;
149
150 wdt = devm_kzalloc(dev, sizeof(struct rn5t618_wdt), GFP_KERNEL);
151 if (!wdt)
152 return -ENOMEM;
153
154 min_timeout = rn5t618_wdt_map[0].time;
155 max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time;
156
157 wdt->rn5t618 = rn5t618;
158 wdt->wdt_dev.info = &rn5t618_wdt_info;
159 wdt->wdt_dev.ops = &rn5t618_wdt_ops;
160 wdt->wdt_dev.min_timeout = min_timeout;
161 wdt->wdt_dev.max_timeout = max_timeout;
162 wdt->wdt_dev.timeout = max_timeout;
163 wdt->wdt_dev.parent = dev;
164
165 /* Read out previous power-off factor */
166 ret = regmap_read(wdt->rn5t618->regmap, RN5T618_POFFHIS, &val);
167 if (ret)
168 return ret;
169
170 if (val & RN5T618_POFFHIS_VINDET)
171 wdt->wdt_dev.bootstatus = WDIOF_POWERUNDER;
172 else if (val & RN5T618_POFFHIS_WDG)
173 wdt->wdt_dev.bootstatus = WDIOF_CARDRESET;
174
175 watchdog_set_drvdata(&wdt->wdt_dev, wdt);
176 watchdog_init_timeout(&wdt->wdt_dev, timeout, dev);
177 watchdog_set_nowayout(&wdt->wdt_dev, nowayout);
178
179 platform_set_drvdata(pdev, wdt);
180
181 return devm_watchdog_register_device(dev, &wdt->wdt_dev);
182}
183
184static struct platform_driver rn5t618_wdt_driver = {
185 .probe = rn5t618_wdt_probe,
186 .driver = {
187 .name = DRIVER_NAME,
188 },
189};
190
191module_platform_driver(rn5t618_wdt_driver);
192
193MODULE_ALIAS("platform:rn5t618-wdt");
194MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
195MODULE_DESCRIPTION("RN5T618 watchdog driver");
196MODULE_LICENSE("GPL v2");