1// SPDX-License-Identifier: GPL-2.0
2/*
3 * MStar WDT driver
4 *
5 * Copyright (C) 2019 - 2021 Daniel Palmer
6 * Copyright (C) 2021 Romain Perier
7 *
8 */
9
10#include <linux/clk.h>
11#include <linux/io.h>
12#include <linux/mod_devicetable.h>
13#include <linux/module.h>
14#include <linux/platform_device.h>
15#include <linux/watchdog.h>
16
17#define REG_WDT_CLR 0x0
18#define REG_WDT_MAX_PRD_L 0x10
19#define REG_WDT_MAX_PRD_H 0x14
20
21#define MSC313E_WDT_MIN_TIMEOUT 1
22#define MSC313E_WDT_DEFAULT_TIMEOUT 30
23
24static unsigned int timeout;
25
26module_param(timeout, int, 0);
27MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
28
29struct msc313e_wdt_priv {
30 void __iomem *base;
31 struct watchdog_device wdev;
32 struct clk *clk;
33};
34
35static int msc313e_wdt_start(struct watchdog_device *wdev)
36{
37 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdd: wdev);
38 u32 timeout;
39 int err;
40
41 err = clk_prepare_enable(clk: priv->clk);
42 if (err)
43 return err;
44
45 timeout = wdev->timeout * clk_get_rate(clk: priv->clk);
46 writew(val: timeout & 0xffff, addr: priv->base + REG_WDT_MAX_PRD_L);
47 writew(val: (timeout >> 16) & 0xffff, addr: priv->base + REG_WDT_MAX_PRD_H);
48 writew(val: 1, addr: priv->base + REG_WDT_CLR);
49 return 0;
50}
51
52static int msc313e_wdt_ping(struct watchdog_device *wdev)
53{
54 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdd: wdev);
55
56 writew(val: 1, addr: priv->base + REG_WDT_CLR);
57 return 0;
58}
59
60static int msc313e_wdt_stop(struct watchdog_device *wdev)
61{
62 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdd: wdev);
63
64 writew(val: 0, addr: priv->base + REG_WDT_MAX_PRD_L);
65 writew(val: 0, addr: priv->base + REG_WDT_MAX_PRD_H);
66 writew(val: 0, addr: priv->base + REG_WDT_CLR);
67 clk_disable_unprepare(clk: priv->clk);
68 return 0;
69}
70
71static int msc313e_wdt_settimeout(struct watchdog_device *wdev, unsigned int new_time)
72{
73 wdev->timeout = new_time;
74
75 return msc313e_wdt_start(wdev);
76}
77
78static const struct watchdog_info msc313e_wdt_ident = {
79 .identity = "MSC313e watchdog",
80 .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
81};
82
83static const struct watchdog_ops msc313e_wdt_ops = {
84 .owner = THIS_MODULE,
85 .start = msc313e_wdt_start,
86 .stop = msc313e_wdt_stop,
87 .ping = msc313e_wdt_ping,
88 .set_timeout = msc313e_wdt_settimeout,
89};
90
91static const struct of_device_id msc313e_wdt_of_match[] = {
92 { .compatible = "mstar,msc313e-wdt", },
93 { /* sentinel */ }
94};
95MODULE_DEVICE_TABLE(of, msc313e_wdt_of_match);
96
97static int msc313e_wdt_probe(struct platform_device *pdev)
98{
99 struct device *dev = &pdev->dev;
100 struct msc313e_wdt_priv *priv;
101
102 priv = devm_kzalloc(dev: &pdev->dev, size: sizeof(*priv), GFP_KERNEL);
103 if (!priv)
104 return -ENOMEM;
105
106 priv->base = devm_platform_ioremap_resource(pdev, index: 0);
107 if (IS_ERR(ptr: priv->base))
108 return PTR_ERR(ptr: priv->base);
109
110 priv->clk = devm_clk_get(dev, NULL);
111 if (IS_ERR(ptr: priv->clk)) {
112 dev_err(dev, "No input clock\n");
113 return PTR_ERR(ptr: priv->clk);
114 }
115
116 priv->wdev.info = &msc313e_wdt_ident,
117 priv->wdev.ops = &msc313e_wdt_ops,
118 priv->wdev.parent = dev;
119 priv->wdev.min_timeout = MSC313E_WDT_MIN_TIMEOUT;
120 priv->wdev.max_timeout = U32_MAX / clk_get_rate(clk: priv->clk);
121 priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT;
122
123 /* If the period is non-zero the WDT is running */
124 if (readw(addr: priv->base + REG_WDT_MAX_PRD_L) | (readw(addr: priv->base + REG_WDT_MAX_PRD_H) << 16))
125 set_bit(WDOG_HW_RUNNING, addr: &priv->wdev.status);
126
127 watchdog_set_drvdata(wdd: &priv->wdev, data: priv);
128
129 watchdog_init_timeout(wdd: &priv->wdev, timeout_parm: timeout, dev);
130 watchdog_stop_on_reboot(wdd: &priv->wdev);
131 watchdog_stop_on_unregister(wdd: &priv->wdev);
132
133 return devm_watchdog_register_device(dev, &priv->wdev);
134}
135
136static int __maybe_unused msc313e_wdt_suspend(struct device *dev)
137{
138 struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);
139
140 if (watchdog_active(wdd: &priv->wdev))
141 msc313e_wdt_stop(wdev: &priv->wdev);
142
143 return 0;
144}
145
146static int __maybe_unused msc313e_wdt_resume(struct device *dev)
147{
148 struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);
149
150 if (watchdog_active(wdd: &priv->wdev))
151 msc313e_wdt_start(wdev: &priv->wdev);
152
153 return 0;
154}
155
156static SIMPLE_DEV_PM_OPS(msc313e_wdt_pm_ops, msc313e_wdt_suspend, msc313e_wdt_resume);
157
158static struct platform_driver msc313e_wdt_driver = {
159 .driver = {
160 .name = "msc313e-wdt",
161 .of_match_table = msc313e_wdt_of_match,
162 .pm = &msc313e_wdt_pm_ops,
163 },
164 .probe = msc313e_wdt_probe,
165};
166module_platform_driver(msc313e_wdt_driver);
167
168MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>");
169MODULE_DESCRIPTION("Watchdog driver for MStar MSC313e");
170MODULE_LICENSE("GPL v2");
171

source code of linux/drivers/watchdog/msc313e_wdt.c