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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Retu watchdog driver
4 *
5 * Copyright (C) 2004, 2005 Nokia Corporation
6 *
7 * Based on code written by Amit Kucheria and Michael Buesch.
8 * Rewritten by Aaro Koskinen.
9 */
10
11#include <linux/devm-helpers.h>
12#include <linux/slab.h>
13#include <linux/errno.h>
14#include <linux/device.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/mfd/retu.h>
18#include <linux/watchdog.h>
19#include <linux/platform_device.h>
20
21/* Watchdog timer values in seconds */
22#define RETU_WDT_MAX_TIMER 63
23
24struct retu_wdt_dev {
25 struct retu_dev *rdev;
26 struct device *dev;
27 struct delayed_work ping_work;
28};
29
30/*
31 * Since Retu watchdog cannot be disabled in hardware, we must kick it
32 * with a timer until userspace watchdog software takes over. If
33 * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
34 */
35static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
36{
37 retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
38 schedule_delayed_work(&wdev->ping_work,
39 round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
40}
41
42static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
43{
44 retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
45 cancel_delayed_work_sync(&wdev->ping_work);
46}
47
48static void retu_wdt_ping_work(struct work_struct *work)
49{
50 struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
51 struct retu_wdt_dev, ping_work);
52 retu_wdt_ping_enable(wdev);
53}
54
55static int retu_wdt_start(struct watchdog_device *wdog)
56{
57 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
58
59 retu_wdt_ping_disable(wdev);
60
61 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
62}
63
64static int retu_wdt_stop(struct watchdog_device *wdog)
65{
66 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
67
68 retu_wdt_ping_enable(wdev);
69
70 return 0;
71}
72
73static int retu_wdt_ping(struct watchdog_device *wdog)
74{
75 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
76
77 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
78}
79
80static int retu_wdt_set_timeout(struct watchdog_device *wdog,
81 unsigned int timeout)
82{
83 struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
84
85 wdog->timeout = timeout;
86 return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
87}
88
89static const struct watchdog_info retu_wdt_info = {
90 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
91 .identity = "Retu watchdog",
92};
93
94static const struct watchdog_ops retu_wdt_ops = {
95 .owner = THIS_MODULE,
96 .start = retu_wdt_start,
97 .stop = retu_wdt_stop,
98 .ping = retu_wdt_ping,
99 .set_timeout = retu_wdt_set_timeout,
100};
101
102static int retu_wdt_probe(struct platform_device *pdev)
103{
104 struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
105 bool nowayout = WATCHDOG_NOWAYOUT;
106 struct watchdog_device *retu_wdt;
107 struct retu_wdt_dev *wdev;
108 int ret;
109
110 retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
111 if (!retu_wdt)
112 return -ENOMEM;
113
114 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
115 if (!wdev)
116 return -ENOMEM;
117
118 retu_wdt->info = &retu_wdt_info;
119 retu_wdt->ops = &retu_wdt_ops;
120 retu_wdt->timeout = RETU_WDT_MAX_TIMER;
121 retu_wdt->min_timeout = 0;
122 retu_wdt->max_timeout = RETU_WDT_MAX_TIMER;
123 retu_wdt->parent = &pdev->dev;
124
125 watchdog_set_drvdata(retu_wdt, wdev);
126 watchdog_set_nowayout(retu_wdt, nowayout);
127
128 wdev->rdev = rdev;
129 wdev->dev = &pdev->dev;
130
131 ret = devm_delayed_work_autocancel(&pdev->dev, &wdev->ping_work,
132 retu_wdt_ping_work);
133 if (ret)
134 return ret;
135
136 ret = devm_watchdog_register_device(&pdev->dev, retu_wdt);
137 if (ret < 0)
138 return ret;
139
140 if (nowayout)
141 retu_wdt_ping(retu_wdt);
142 else
143 retu_wdt_ping_enable(wdev);
144
145 return 0;
146}
147
148static struct platform_driver retu_wdt_driver = {
149 .probe = retu_wdt_probe,
150 .driver = {
151 .name = "retu-wdt",
152 },
153};
154module_platform_driver(retu_wdt_driver);
155
156MODULE_ALIAS("platform:retu-wdt");
157MODULE_DESCRIPTION("Retu watchdog");
158MODULE_AUTHOR("Amit Kucheria");
159MODULE_AUTHOR("Aaro Koskinen <[email protected]>");
160MODULE_LICENSE("GPL");