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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(wdev);
38 u32 timeout;
39 int err;
40
41 err = clk_prepare_enable(priv->clk);
42 if (err)
43 return err;
44
45 timeout = wdev->timeout * clk_get_rate(priv->clk);
46 writew(timeout & 0xffff, priv->base + REG_WDT_MAX_PRD_L);
47 writew((timeout >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H);
48 writew(1, 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(wdev);
55
56 writew(1, 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(wdev);
63
64 writew(0, priv->base + REG_WDT_MAX_PRD_L);
65 writew(0, priv->base + REG_WDT_MAX_PRD_H);
66 writew(0, priv->base + REG_WDT_CLR);
67 clk_disable_unprepare(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 { }
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(&pdev->dev, sizeof(*priv), GFP_KERNEL);
103 if (!priv)
104 return -ENOMEM;
105
106 priv->base = devm_platform_ioremap_resource(pdev, 0);
107 if (IS_ERR(priv->base))
108 return PTR_ERR(priv->base);
109
110 priv->clk = devm_clk_get(dev, NULL);
111 if (IS_ERR(priv->clk)) {
112 dev_err(dev, "No input clock\n");
113 return PTR_ERR(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(priv->clk);
121 priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT;
122
123 watchdog_set_drvdata(&priv->wdev, priv);
124
125 watchdog_init_timeout(&priv->wdev, timeout, dev);
126 watchdog_stop_on_reboot(&priv->wdev);
127 watchdog_stop_on_unregister(&priv->wdev);
128
129 return devm_watchdog_register_device(dev, &priv->wdev);
130}
131
132static int __maybe_unused msc313e_wdt_suspend(struct device *dev)
133{
134 struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);
135
136 if (watchdog_active(&priv->wdev))
137 msc313e_wdt_stop(&priv->wdev);
138
139 return 0;
140}
141
142static int __maybe_unused msc313e_wdt_resume(struct device *dev)
143{
144 struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);
145
146 if (watchdog_active(&priv->wdev))
147 msc313e_wdt_start(&priv->wdev);
148
149 return 0;
150}
151
152static SIMPLE_DEV_PM_OPS(msc313e_wdt_pm_ops, msc313e_wdt_suspend, msc313e_wdt_resume);
153
154static struct platform_driver msc313e_wdt_driver = {
155 .driver = {
156 .name = "msc313e-wdt",
157 .of_match_table = msc313e_wdt_of_match,
158 .pm = &msc313e_wdt_pm_ops,
159 },
160 .probe = msc313e_wdt_probe,
161};
162module_platform_driver(msc313e_wdt_driver);
163
164MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>");
165MODULE_DESCRIPTION("Watchdog driver for MStar MSC313e");
166MODULE_LICENSE("GPL v2");
167
