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 | |
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(wdd: wdt_dev); |
37 | |
38 | writel(val: 1, addr: moxart_wdt->base + REG_COUNT); |
39 | writel(val: 0x5ab9, addr: moxart_wdt->base + REG_MODE); |
40 | writel(val: 0x03, addr: moxart_wdt->base + REG_ENABLE); |
41 | |
42 | return 0; |
43 | } |
44 | |
45 | static int moxart_wdt_stop(struct watchdog_device *wdt_dev) |
46 | { |
47 | struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdd: wdt_dev); |
48 | |
49 | writel(val: 0, addr: moxart_wdt->base + REG_ENABLE); |
50 | |
51 | return 0; |
52 | } |
53 | |
54 | static int moxart_wdt_start(struct watchdog_device *wdt_dev) |
55 | { |
56 | struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdd: wdt_dev); |
57 | |
58 | writel(val: moxart_wdt->clock_frequency * wdt_dev->timeout, |
59 | addr: moxart_wdt->base + REG_COUNT); |
60 | writel(val: 0x5ab9, addr: moxart_wdt->base + REG_MODE); |
61 | writel(val: 0x03, addr: moxart_wdt->base + REG_ENABLE); |
62 | |
63 | return 0; |
64 | } |
65 | |
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 | |
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, size: sizeof(*moxart_wdt), GFP_KERNEL); |
98 | if (!moxart_wdt) |
99 | return -ENOMEM; |
100 | |
101 | platform_set_drvdata(pdev, data: moxart_wdt); |
102 | |
103 | moxart_wdt->base = devm_platform_ioremap_resource(pdev, index: 0); |
104 | if (IS_ERR(ptr: moxart_wdt->base)) |
105 | return PTR_ERR(ptr: moxart_wdt->base); |
106 | |
107 | clk = devm_clk_get(dev, NULL); |
108 | if (IS_ERR(ptr: clk)) { |
109 | pr_err("%s: of_clk_get failed\n" , __func__); |
110 | return PTR_ERR(ptr: 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(wdd: &moxart_wdt->dev, timeout_parm: heartbeat, dev); |
129 | watchdog_set_nowayout(wdd: &moxart_wdt->dev, nowayout); |
130 | watchdog_set_restart_priority(wdd: &moxart_wdt->dev, priority: 128); |
131 | |
132 | watchdog_set_drvdata(wdd: &moxart_wdt->dev, data: moxart_wdt); |
133 | |
134 | watchdog_stop_on_unregister(wdd: &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 | |