1 /*
2 * Realtek RTD129x watchdog
3 *
4 * Copyright (c) 2017 Andreas Färber
5 *
6 * SPDX-License-Identifier: GPL-2.0+
7 */
8
9 #include <linux/bitops.h>
10 #include <linux/clk.h>
11 #include <linux/io.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14 #include <linux/platform_device.h>
15 #include <linux/watchdog.h>
16
17 #define RTD119X_TCWCR 0x0
18 #define RTD119X_TCWTR 0x4
19 #define RTD119X_TCWOV 0xc
20
21 #define RTD119X_TCWCR_WDEN_DISABLED 0xa5
22 #define RTD119X_TCWCR_WDEN_ENABLED 0xff
23 #define RTD119X_TCWCR_WDEN_MASK 0xff
24
25 #define RTD119X_TCWTR_WDCLR BIT(0)
26
27 struct rtd119x_watchdog_device {
28 struct watchdog_device wdt_dev;
29 void __iomem *base;
30 struct clk *clk;
31 };
32
rtd119x_wdt_start(struct watchdog_device * wdev)33 static int rtd119x_wdt_start(struct watchdog_device *wdev)
34 {
35 struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
36 u32 val;
37
38 val = readl_relaxed(data->base + RTD119X_TCWCR);
39 val &= ~RTD119X_TCWCR_WDEN_MASK;
40 val |= RTD119X_TCWCR_WDEN_ENABLED;
41 writel(val, data->base + RTD119X_TCWCR);
42
43 return 0;
44 }
45
rtd119x_wdt_stop(struct watchdog_device * wdev)46 static int rtd119x_wdt_stop(struct watchdog_device *wdev)
47 {
48 struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
49 u32 val;
50
51 val = readl_relaxed(data->base + RTD119X_TCWCR);
52 val &= ~RTD119X_TCWCR_WDEN_MASK;
53 val |= RTD119X_TCWCR_WDEN_DISABLED;
54 writel(val, data->base + RTD119X_TCWCR);
55
56 return 0;
57 }
58
rtd119x_wdt_ping(struct watchdog_device * wdev)59 static int rtd119x_wdt_ping(struct watchdog_device *wdev)
60 {
61 struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
62
63 writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
64
65 return rtd119x_wdt_start(wdev);
66 }
67
rtd119x_wdt_set_timeout(struct watchdog_device * wdev,unsigned int val)68 static int rtd119x_wdt_set_timeout(struct watchdog_device *wdev, unsigned int val)
69 {
70 struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
71
72 writel(val * clk_get_rate(data->clk), data->base + RTD119X_TCWOV);
73
74 data->wdt_dev.timeout = val;
75
76 return 0;
77 }
78
79 static const struct watchdog_ops rtd119x_wdt_ops = {
80 .owner = THIS_MODULE,
81 .start = rtd119x_wdt_start,
82 .stop = rtd119x_wdt_stop,
83 .ping = rtd119x_wdt_ping,
84 .set_timeout = rtd119x_wdt_set_timeout,
85 };
86
87 static const struct watchdog_info rtd119x_wdt_info = {
88 .identity = "rtd119x-wdt",
89 .options = 0,
90 };
91
92 static const struct of_device_id rtd119x_wdt_dt_ids[] = {
93 { .compatible = "realtek,rtd1295-watchdog" },
94 { }
95 };
96
rtd119x_clk_disable_unprepare(void * data)97 static void rtd119x_clk_disable_unprepare(void *data)
98 {
99 clk_disable_unprepare(data);
100 }
101
rtd119x_wdt_probe(struct platform_device * pdev)102 static int rtd119x_wdt_probe(struct platform_device *pdev)
103 {
104 struct device *dev = &pdev->dev;
105 struct rtd119x_watchdog_device *data;
106 int ret;
107
108 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
109 if (!data)
110 return -ENOMEM;
111
112 data->base = devm_platform_ioremap_resource(pdev, 0);
113 if (IS_ERR(data->base))
114 return PTR_ERR(data->base);
115
116 data->clk = devm_clk_get(dev, NULL);
117 if (IS_ERR(data->clk))
118 return PTR_ERR(data->clk);
119
120 ret = clk_prepare_enable(data->clk);
121 if (ret)
122 return ret;
123 ret = devm_add_action_or_reset(dev, rtd119x_clk_disable_unprepare,
124 data->clk);
125 if (ret)
126 return ret;
127
128 data->wdt_dev.info = &rtd119x_wdt_info;
129 data->wdt_dev.ops = &rtd119x_wdt_ops;
130 data->wdt_dev.timeout = 120;
131 data->wdt_dev.max_timeout = 0xffffffff / clk_get_rate(data->clk);
132 data->wdt_dev.min_timeout = 1;
133 data->wdt_dev.parent = dev;
134
135 watchdog_stop_on_reboot(&data->wdt_dev);
136 watchdog_set_drvdata(&data->wdt_dev, data);
137 platform_set_drvdata(pdev, data);
138
139 writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
140 rtd119x_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
141 rtd119x_wdt_stop(&data->wdt_dev);
142
143 return devm_watchdog_register_device(dev, &data->wdt_dev);
144 }
145
146 static struct platform_driver rtd119x_wdt_driver = {
147 .probe = rtd119x_wdt_probe,
148 .driver = {
149 .name = "rtd1295-watchdog",
150 .of_match_table = rtd119x_wdt_dt_ids,
151 },
152 };
153 builtin_platform_driver(rtd119x_wdt_driver);
154