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2e62c498 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
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2 | /* |
3 | * Watchdog driver for Conexant Digicolor | |
4 | * | |
5 | * Copyright (C) 2015 Paradox Innovation Ltd. | |
6 | * | |
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7 | */ |
8 | ||
9 | #include <linux/types.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/io.h> | |
12 | #include <linux/delay.h> | |
13 | #include <linux/clk.h> | |
14 | #include <linux/watchdog.h> | |
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15 | #include <linux/platform_device.h> |
16 | #include <linux/of_address.h> | |
17 | ||
18 | #define TIMER_A_CONTROL 0 | |
19 | #define TIMER_A_COUNT 4 | |
20 | ||
21 | #define TIMER_A_ENABLE_COUNT BIT(0) | |
22 | #define TIMER_A_ENABLE_WATCHDOG BIT(1) | |
23 | ||
24 | struct dc_wdt { | |
25 | void __iomem *base; | |
26 | struct clk *clk; | |
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27 | spinlock_t lock; |
28 | }; | |
29 | ||
30 | static unsigned timeout; | |
31 | module_param(timeout, uint, 0); | |
32 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); | |
33 | ||
34 | static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks) | |
35 | { | |
36 | unsigned long flags; | |
37 | ||
38 | spin_lock_irqsave(&wdt->lock, flags); | |
39 | ||
40 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); | |
41 | writel_relaxed(ticks, wdt->base + TIMER_A_COUNT); | |
42 | writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG, | |
43 | wdt->base + TIMER_A_CONTROL); | |
44 | ||
45 | spin_unlock_irqrestore(&wdt->lock, flags); | |
46 | } | |
47 | ||
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48 | static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action, |
49 | void *data) | |
336694a0 | 50 | { |
d3b08185 | 51 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); |
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52 | |
53 | dc_wdt_set(wdt, 1); | |
54 | /* wait for reset to assert... */ | |
55 | mdelay(500); | |
56 | ||
d3b08185 | 57 | return 0; |
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58 | } |
59 | ||
60 | static int dc_wdt_start(struct watchdog_device *wdog) | |
61 | { | |
62 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
63 | ||
64 | dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk)); | |
65 | ||
66 | return 0; | |
67 | } | |
68 | ||
69 | static int dc_wdt_stop(struct watchdog_device *wdog) | |
70 | { | |
71 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
72 | ||
73 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); | |
74 | ||
75 | return 0; | |
76 | } | |
77 | ||
78 | static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) | |
79 | { | |
80 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
81 | ||
82 | dc_wdt_set(wdt, t * clk_get_rate(wdt->clk)); | |
83 | wdog->timeout = t; | |
84 | ||
85 | return 0; | |
86 | } | |
87 | ||
88 | static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog) | |
89 | { | |
90 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
91 | uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT); | |
92 | ||
93 | return count / clk_get_rate(wdt->clk); | |
94 | } | |
95 | ||
b893e344 | 96 | static const struct watchdog_ops dc_wdt_ops = { |
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97 | .owner = THIS_MODULE, |
98 | .start = dc_wdt_start, | |
99 | .stop = dc_wdt_stop, | |
100 | .set_timeout = dc_wdt_set_timeout, | |
101 | .get_timeleft = dc_wdt_get_timeleft, | |
d3b08185 | 102 | .restart = dc_wdt_restart, |
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103 | }; |
104 | ||
6c368932 | 105 | static const struct watchdog_info dc_wdt_info = { |
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106 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
107 | | WDIOF_KEEPALIVEPING, | |
108 | .identity = "Conexant Digicolor Watchdog", | |
109 | }; | |
110 | ||
111 | static struct watchdog_device dc_wdt_wdd = { | |
112 | .info = &dc_wdt_info, | |
113 | .ops = &dc_wdt_ops, | |
114 | .min_timeout = 1, | |
115 | }; | |
116 | ||
117 | static int dc_wdt_probe(struct platform_device *pdev) | |
118 | { | |
dd36f6ce | 119 | struct resource *res; |
336694a0 | 120 | struct device *dev = &pdev->dev; |
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121 | struct dc_wdt *wdt; |
122 | int ret; | |
123 | ||
124 | wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL); | |
125 | if (!wdt) | |
126 | return -ENOMEM; | |
336694a0 | 127 | |
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128 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
129 | wdt->base = devm_ioremap_resource(dev, res); | |
130 | if (IS_ERR(wdt->base)) | |
131 | return PTR_ERR(wdt->base); | |
336694a0 | 132 | |
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133 | wdt->clk = devm_clk_get(dev, NULL); |
134 | if (IS_ERR(wdt->clk)) | |
135 | return PTR_ERR(wdt->clk); | |
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136 | dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk); |
137 | dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout; | |
dd36f6ce | 138 | dc_wdt_wdd.parent = dev; |
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139 | |
140 | spin_lock_init(&wdt->lock); | |
141 | ||
142 | watchdog_set_drvdata(&dc_wdt_wdd, wdt); | |
d3b08185 | 143 | watchdog_set_restart_priority(&dc_wdt_wdd, 128); |
336694a0 | 144 | watchdog_init_timeout(&dc_wdt_wdd, timeout, dev); |
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145 | watchdog_stop_on_reboot(&dc_wdt_wdd); |
146 | ret = devm_watchdog_register_device(dev, &dc_wdt_wdd); | |
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147 | if (ret) { |
148 | dev_err(dev, "Failed to register watchdog device"); | |
dd36f6ce | 149 | return ret; |
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150 | } |
151 | ||
336694a0 | 152 | return 0; |
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153 | } |
154 | ||
155 | static const struct of_device_id dc_wdt_of_match[] = { | |
156 | { .compatible = "cnxt,cx92755-wdt", }, | |
157 | {}, | |
158 | }; | |
159 | MODULE_DEVICE_TABLE(of, dc_wdt_of_match); | |
160 | ||
161 | static struct platform_driver dc_wdt_driver = { | |
162 | .probe = dc_wdt_probe, | |
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163 | .driver = { |
164 | .name = "digicolor-wdt", | |
165 | .of_match_table = dc_wdt_of_match, | |
166 | }, | |
167 | }; | |
168 | module_platform_driver(dc_wdt_driver); | |
169 | ||
170 | MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); | |
171 | MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer"); | |
172 | MODULE_LICENSE("GPL"); |