Merge remote-tracking branch 'stable/linux-5.15.y' into rpi-5.15.y
[platform/kernel/linux-rpi.git] / drivers / watchdog / rtd119x_wdt.c
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
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
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
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
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
97 static void rtd119x_clk_disable_unprepare(void *data)
98 {
99         clk_disable_unprepare(data);
100 }
101
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);