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1 | /* |
2 | * Watchdog driver for Conexant Digicolor | |
3 | * | |
4 | * Copyright (C) 2015 Paradox Innovation Ltd. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License as published by the | |
8 | * Free Software Foundation; either version 2 of the License, or (at your | |
9 | * option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/delay.h> | |
16 | #include <linux/clk.h> | |
17 | #include <linux/watchdog.h> | |
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18 | #include <linux/platform_device.h> |
19 | #include <linux/of_address.h> | |
20 | ||
21 | #define TIMER_A_CONTROL 0 | |
22 | #define TIMER_A_COUNT 4 | |
23 | ||
24 | #define TIMER_A_ENABLE_COUNT BIT(0) | |
25 | #define TIMER_A_ENABLE_WATCHDOG BIT(1) | |
26 | ||
27 | struct dc_wdt { | |
28 | void __iomem *base; | |
29 | struct clk *clk; | |
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30 | spinlock_t lock; |
31 | }; | |
32 | ||
33 | static unsigned timeout; | |
34 | module_param(timeout, uint, 0); | |
35 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); | |
36 | ||
37 | static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks) | |
38 | { | |
39 | unsigned long flags; | |
40 | ||
41 | spin_lock_irqsave(&wdt->lock, flags); | |
42 | ||
43 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); | |
44 | writel_relaxed(ticks, wdt->base + TIMER_A_COUNT); | |
45 | writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG, | |
46 | wdt->base + TIMER_A_CONTROL); | |
47 | ||
48 | spin_unlock_irqrestore(&wdt->lock, flags); | |
49 | } | |
50 | ||
4d8b229d GR |
51 | static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action, |
52 | void *data) | |
336694a0 | 53 | { |
d3b08185 | 54 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); |
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55 | |
56 | dc_wdt_set(wdt, 1); | |
57 | /* wait for reset to assert... */ | |
58 | mdelay(500); | |
59 | ||
d3b08185 | 60 | return 0; |
336694a0 BS |
61 | } |
62 | ||
63 | static int dc_wdt_start(struct watchdog_device *wdog) | |
64 | { | |
65 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
66 | ||
67 | dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk)); | |
68 | ||
69 | return 0; | |
70 | } | |
71 | ||
72 | static int dc_wdt_stop(struct watchdog_device *wdog) | |
73 | { | |
74 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
75 | ||
76 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) | |
82 | { | |
83 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
84 | ||
85 | dc_wdt_set(wdt, t * clk_get_rate(wdt->clk)); | |
86 | wdog->timeout = t; | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog) | |
92 | { | |
93 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
94 | uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT); | |
95 | ||
96 | return count / clk_get_rate(wdt->clk); | |
97 | } | |
98 | ||
b893e344 | 99 | static const struct watchdog_ops dc_wdt_ops = { |
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100 | .owner = THIS_MODULE, |
101 | .start = dc_wdt_start, | |
102 | .stop = dc_wdt_stop, | |
103 | .set_timeout = dc_wdt_set_timeout, | |
104 | .get_timeleft = dc_wdt_get_timeleft, | |
d3b08185 | 105 | .restart = dc_wdt_restart, |
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106 | }; |
107 | ||
6c368932 | 108 | static const struct watchdog_info dc_wdt_info = { |
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109 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
110 | | WDIOF_KEEPALIVEPING, | |
111 | .identity = "Conexant Digicolor Watchdog", | |
112 | }; | |
113 | ||
114 | static struct watchdog_device dc_wdt_wdd = { | |
115 | .info = &dc_wdt_info, | |
116 | .ops = &dc_wdt_ops, | |
117 | .min_timeout = 1, | |
118 | }; | |
119 | ||
120 | static int dc_wdt_probe(struct platform_device *pdev) | |
121 | { | |
dd36f6ce | 122 | struct resource *res; |
336694a0 | 123 | struct device *dev = &pdev->dev; |
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124 | struct dc_wdt *wdt; |
125 | int ret; | |
126 | ||
127 | wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL); | |
128 | if (!wdt) | |
129 | return -ENOMEM; | |
336694a0 | 130 | |
dd36f6ce GR |
131 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
132 | wdt->base = devm_ioremap_resource(dev, res); | |
133 | if (IS_ERR(wdt->base)) | |
134 | return PTR_ERR(wdt->base); | |
336694a0 | 135 | |
dd36f6ce GR |
136 | wdt->clk = devm_clk_get(dev, NULL); |
137 | if (IS_ERR(wdt->clk)) | |
138 | return PTR_ERR(wdt->clk); | |
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139 | dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk); |
140 | dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout; | |
dd36f6ce | 141 | dc_wdt_wdd.parent = dev; |
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142 | |
143 | spin_lock_init(&wdt->lock); | |
144 | ||
145 | watchdog_set_drvdata(&dc_wdt_wdd, wdt); | |
d3b08185 | 146 | watchdog_set_restart_priority(&dc_wdt_wdd, 128); |
336694a0 | 147 | watchdog_init_timeout(&dc_wdt_wdd, timeout, dev); |
dd36f6ce GR |
148 | watchdog_stop_on_reboot(&dc_wdt_wdd); |
149 | ret = devm_watchdog_register_device(dev, &dc_wdt_wdd); | |
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150 | if (ret) { |
151 | dev_err(dev, "Failed to register watchdog device"); | |
dd36f6ce | 152 | return ret; |
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153 | } |
154 | ||
336694a0 | 155 | return 0; |
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156 | } |
157 | ||
158 | static const struct of_device_id dc_wdt_of_match[] = { | |
159 | { .compatible = "cnxt,cx92755-wdt", }, | |
160 | {}, | |
161 | }; | |
162 | MODULE_DEVICE_TABLE(of, dc_wdt_of_match); | |
163 | ||
164 | static struct platform_driver dc_wdt_driver = { | |
165 | .probe = dc_wdt_probe, | |
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166 | .driver = { |
167 | .name = "digicolor-wdt", | |
168 | .of_match_table = dc_wdt_of_match, | |
169 | }, | |
170 | }; | |
171 | module_platform_driver(dc_wdt_driver); | |
172 | ||
173 | MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); | |
174 | MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer"); | |
175 | MODULE_LICENSE("GPL"); |