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e14538e0 JJ |
1 | /* |
2 | * MOXA ART SoCs watchdog driver. | |
3 | * | |
4 | * Copyright (C) 2013 Jonas Jensen | |
5 | * | |
6 | * Jonas Jensen <jonas.jensen@gmail.com> | |
7 | * | |
8 | * This file is licensed under the terms of the GNU General Public | |
9 | * License version 2. This program is licensed "as is" without any | |
10 | * warranty of any kind, whether express or implied. | |
11 | */ | |
12 | ||
13 | #include <linux/clk.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/watchdog.h> | |
20 | #include <linux/moduleparam.h> | |
21 | ||
22 | #define REG_COUNT 0x4 | |
23 | #define REG_MODE 0x8 | |
24 | #define REG_ENABLE 0xC | |
25 | ||
26 | struct moxart_wdt_dev { | |
27 | struct watchdog_device dev; | |
28 | void __iomem *base; | |
29 | unsigned int clock_frequency; | |
30 | }; | |
31 | ||
32 | static int heartbeat; | |
33 | ||
34 | static int moxart_wdt_stop(struct watchdog_device *wdt_dev) | |
35 | { | |
36 | struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); | |
37 | ||
38 | writel(0, moxart_wdt->base + REG_ENABLE); | |
39 | ||
40 | return 0; | |
41 | } | |
42 | ||
43 | static int moxart_wdt_start(struct watchdog_device *wdt_dev) | |
44 | { | |
45 | struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); | |
46 | ||
47 | writel(moxart_wdt->clock_frequency * wdt_dev->timeout, | |
48 | moxart_wdt->base + REG_COUNT); | |
49 | writel(0x5ab9, moxart_wdt->base + REG_MODE); | |
50 | writel(0x03, moxart_wdt->base + REG_ENABLE); | |
51 | ||
52 | return 0; | |
53 | } | |
54 | ||
55 | static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
56 | unsigned int timeout) | |
57 | { | |
58 | wdt_dev->timeout = timeout; | |
59 | ||
60 | return 0; | |
61 | } | |
62 | ||
63 | static const struct watchdog_info moxart_wdt_info = { | |
64 | .identity = "moxart-wdt", | |
65 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
66 | WDIOF_MAGICCLOSE, | |
67 | }; | |
68 | ||
69 | static const struct watchdog_ops moxart_wdt_ops = { | |
70 | .owner = THIS_MODULE, | |
71 | .start = moxart_wdt_start, | |
72 | .stop = moxart_wdt_stop, | |
73 | .set_timeout = moxart_wdt_set_timeout, | |
74 | }; | |
75 | ||
76 | static int moxart_wdt_probe(struct platform_device *pdev) | |
77 | { | |
78 | struct moxart_wdt_dev *moxart_wdt; | |
79 | struct device *dev = &pdev->dev; | |
80 | struct device_node *node = dev->of_node; | |
81 | struct resource *res; | |
82 | struct clk *clk; | |
83 | int err; | |
84 | unsigned int max_timeout; | |
85 | bool nowayout = WATCHDOG_NOWAYOUT; | |
86 | ||
87 | moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); | |
88 | if (!moxart_wdt) | |
89 | return -ENOMEM; | |
90 | ||
91 | platform_set_drvdata(pdev, moxart_wdt); | |
92 | ||
93 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
94 | moxart_wdt->base = devm_ioremap_resource(dev, res); | |
95 | if (IS_ERR(moxart_wdt->base)) | |
96 | return PTR_ERR(moxart_wdt->base); | |
97 | ||
98 | clk = of_clk_get(node, 0); | |
99 | if (IS_ERR(clk)) { | |
100 | pr_err("%s: of_clk_get failed\n", __func__); | |
101 | return PTR_ERR(clk); | |
102 | } | |
103 | ||
104 | moxart_wdt->clock_frequency = clk_get_rate(clk); | |
105 | if (moxart_wdt->clock_frequency == 0) { | |
106 | pr_err("%s: incorrect clock frequency\n", __func__); | |
107 | return -EINVAL; | |
108 | } | |
109 | ||
110 | max_timeout = UINT_MAX / moxart_wdt->clock_frequency; | |
111 | ||
112 | moxart_wdt->dev.info = &moxart_wdt_info; | |
113 | moxart_wdt->dev.ops = &moxart_wdt_ops; | |
114 | moxart_wdt->dev.timeout = max_timeout; | |
115 | moxart_wdt->dev.min_timeout = 1; | |
116 | moxart_wdt->dev.max_timeout = max_timeout; | |
117 | moxart_wdt->dev.parent = dev; | |
118 | ||
119 | watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); | |
120 | watchdog_set_nowayout(&moxart_wdt->dev, nowayout); | |
121 | ||
122 | watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); | |
123 | ||
124 | err = watchdog_register_device(&moxart_wdt->dev); | |
125 | if (err) | |
126 | return err; | |
127 | ||
128 | dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", | |
129 | moxart_wdt->dev.timeout, nowayout); | |
130 | ||
131 | return 0; | |
132 | } | |
133 | ||
134 | static int moxart_wdt_remove(struct platform_device *pdev) | |
135 | { | |
136 | struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); | |
137 | ||
138 | moxart_wdt_stop(&moxart_wdt->dev); | |
139 | watchdog_unregister_device(&moxart_wdt->dev); | |
140 | ||
141 | return 0; | |
142 | } | |
143 | ||
144 | static const struct of_device_id moxart_watchdog_match[] = { | |
145 | { .compatible = "moxa,moxart-watchdog" }, | |
146 | { }, | |
147 | }; | |
148 | ||
149 | static struct platform_driver moxart_wdt_driver = { | |
150 | .probe = moxart_wdt_probe, | |
151 | .remove = moxart_wdt_remove, | |
152 | .driver = { | |
153 | .name = "moxart-watchdog", | |
154 | .owner = THIS_MODULE, | |
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>"); |