1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * MOXA ART SoCs watchdog driver.
4 *
5 * Copyright (C) 2013 Jonas Jensen
6 *
7 * Jonas Jensen <jonas.jensen@gmail.com>
8 *
9 */
10
11 #include <linux/clk.h>
12 #include <linux/io.h>
13 #include <linux/module.h>
14 #include <linux/mod_devicetable.h>
15 #include <linux/err.h>
16 #include <linux/kernel.h>
17 #include <linux/platform_device.h>
18 #include <linux/watchdog.h>
19 #include <linux/moduleparam.h>
20
21 #define REG_COUNT 0x4
22 #define REG_MODE 0x8
23 #define REG_ENABLE 0xC
24
25 struct moxart_wdt_dev {
26 struct watchdog_device dev;
27 void __iomem *base;
28 unsigned int clock_frequency;
29 };
30
31 static int heartbeat;
32
moxart_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)33 static int moxart_wdt_restart(struct watchdog_device *wdt_dev,
34 unsigned long action, void *data)
35 {
36 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
37
38 writel(1, moxart_wdt->base + REG_COUNT);
39 writel(0x5ab9, moxart_wdt->base + REG_MODE);
40 writel(0x03, moxart_wdt->base + REG_ENABLE);
41
42 return 0;
43 }
44
moxart_wdt_stop(struct watchdog_device * wdt_dev)45 static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
46 {
47 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
48
49 writel(0, moxart_wdt->base + REG_ENABLE);
50
51 return 0;
52 }
53
moxart_wdt_start(struct watchdog_device * wdt_dev)54 static int moxart_wdt_start(struct watchdog_device *wdt_dev)
55 {
56 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
57
58 writel(moxart_wdt->clock_frequency * wdt_dev->timeout,
59 moxart_wdt->base + REG_COUNT);
60 writel(0x5ab9, moxart_wdt->base + REG_MODE);
61 writel(0x03, moxart_wdt->base + REG_ENABLE);
62
63 return 0;
64 }
65
moxart_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)66 static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,
67 unsigned int timeout)
68 {
69 wdt_dev->timeout = timeout;
70
71 return 0;
72 }
73
74 static const struct watchdog_info moxart_wdt_info = {
75 .identity = "moxart-wdt",
76 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
77 WDIOF_MAGICCLOSE,
78 };
79
80 static const struct watchdog_ops moxart_wdt_ops = {
81 .owner = THIS_MODULE,
82 .start = moxart_wdt_start,
83 .stop = moxart_wdt_stop,
84 .set_timeout = moxart_wdt_set_timeout,
85 .restart = moxart_wdt_restart,
86 };
87
moxart_wdt_probe(struct platform_device * pdev)88 static int moxart_wdt_probe(struct platform_device *pdev)
89 {
90 struct moxart_wdt_dev *moxart_wdt;
91 struct device *dev = &pdev->dev;
92 struct clk *clk;
93 int err;
94 unsigned int max_timeout;
95 bool nowayout = WATCHDOG_NOWAYOUT;
96
97 moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL);
98 if (!moxart_wdt)
99 return -ENOMEM;
100
101 platform_set_drvdata(pdev, moxart_wdt);
102
103 moxart_wdt->base = devm_platform_ioremap_resource(pdev, 0);
104 if (IS_ERR(moxart_wdt->base))
105 return PTR_ERR(moxart_wdt->base);
106
107 clk = devm_clk_get(dev, NULL);
108 if (IS_ERR(clk)) {
109 pr_err("%s: of_clk_get failed\n", __func__);
110 return PTR_ERR(clk);
111 }
112
113 moxart_wdt->clock_frequency = clk_get_rate(clk);
114 if (moxart_wdt->clock_frequency == 0) {
115 pr_err("%s: incorrect clock frequency\n", __func__);
116 return -EINVAL;
117 }
118
119 max_timeout = UINT_MAX / moxart_wdt->clock_frequency;
120
121 moxart_wdt->dev.info = &moxart_wdt_info;
122 moxart_wdt->dev.ops = &moxart_wdt_ops;
123 moxart_wdt->dev.timeout = max_timeout;
124 moxart_wdt->dev.min_timeout = 1;
125 moxart_wdt->dev.max_timeout = max_timeout;
126 moxart_wdt->dev.parent = dev;
127
128 watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev);
129 watchdog_set_nowayout(&moxart_wdt->dev, nowayout);
130 watchdog_set_restart_priority(&moxart_wdt->dev, 128);
131
132 watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);
133
134 watchdog_stop_on_unregister(&moxart_wdt->dev);
135 err = devm_watchdog_register_device(dev, &moxart_wdt->dev);
136 if (err)
137 return err;
138
139 dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
140 moxart_wdt->dev.timeout, nowayout);
141
142 return 0;
143 }
144
145 static const struct of_device_id moxart_watchdog_match[] = {
146 { .compatible = "moxa,moxart-watchdog" },
147 { },
148 };
149 MODULE_DEVICE_TABLE(of, moxart_watchdog_match);
150
151 static struct platform_driver moxart_wdt_driver = {
152 .probe = moxart_wdt_probe,
153 .driver = {
154 .name = "moxart-watchdog",
155 .of_match_table = moxart_watchdog_match,
156 },
157 };
158 module_platform_driver(moxart_wdt_driver);
159
160 module_param(heartbeat, int, 0);
161 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
162
163 MODULE_DESCRIPTION("MOXART watchdog driver");
164 MODULE_LICENSE("GPL");
165 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
166