1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * Realtek RTD129x watchdog |
4 | * |
5 | * Copyright (c) 2017 Andreas Färber |
6 | * |
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(wdd: 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, addr: 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(wdd: 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, addr: 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(wdd: 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(wdd: wdev); |
71 | |
72 | writel(val: val * clk_get_rate(clk: data->clk), addr: 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 int rtd119x_wdt_probe(struct platform_device *pdev) |
98 | { |
99 | struct device *dev = &pdev->dev; |
100 | struct rtd119x_watchdog_device *data; |
101 | |
102 | data = devm_kzalloc(dev, size: sizeof(*data), GFP_KERNEL); |
103 | if (!data) |
104 | return -ENOMEM; |
105 | |
106 | data->base = devm_platform_ioremap_resource(pdev, index: 0); |
107 | if (IS_ERR(ptr: data->base)) |
108 | return PTR_ERR(ptr: data->base); |
109 | |
110 | data->clk = devm_clk_get_enabled(dev, NULL); |
111 | if (IS_ERR(ptr: data->clk)) |
112 | return PTR_ERR(ptr: data->clk); |
113 | |
114 | data->wdt_dev.info = &rtd119x_wdt_info; |
115 | data->wdt_dev.ops = &rtd119x_wdt_ops; |
116 | data->wdt_dev.timeout = 120; |
117 | data->wdt_dev.max_timeout = 0xffffffff / clk_get_rate(clk: data->clk); |
118 | data->wdt_dev.min_timeout = 1; |
119 | data->wdt_dev.parent = dev; |
120 | |
121 | watchdog_stop_on_reboot(wdd: &data->wdt_dev); |
122 | watchdog_set_drvdata(wdd: &data->wdt_dev, data); |
123 | platform_set_drvdata(pdev, data); |
124 | |
125 | writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR); |
126 | rtd119x_wdt_set_timeout(wdev: &data->wdt_dev, val: data->wdt_dev.timeout); |
127 | rtd119x_wdt_stop(wdev: &data->wdt_dev); |
128 | |
129 | return devm_watchdog_register_device(dev, &data->wdt_dev); |
130 | } |
131 | |
132 | static struct platform_driver rtd119x_wdt_driver = { |
133 | .probe = rtd119x_wdt_probe, |
134 | .driver = { |
135 | .name = "rtd1295-watchdog" , |
136 | .of_match_table = rtd119x_wdt_dt_ids, |
137 | }, |
138 | }; |
139 | builtin_platform_driver(rtd119x_wdt_driver); |
140 | |