Commit | Line | Data |
---|---|---|
336694a0 BS |
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> | |
336694a0 BS |
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; | |
336694a0 BS |
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 | ||
d3b08185 | 51 | static int dc_wdt_restart(struct watchdog_device *wdog) |
336694a0 | 52 | { |
d3b08185 | 53 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); |
336694a0 BS |
54 | |
55 | dc_wdt_set(wdt, 1); | |
56 | /* wait for reset to assert... */ | |
57 | mdelay(500); | |
58 | ||
d3b08185 | 59 | return 0; |
336694a0 BS |
60 | } |
61 | ||
62 | static int dc_wdt_start(struct watchdog_device *wdog) | |
63 | { | |
64 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
65 | ||
66 | dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk)); | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | static int dc_wdt_stop(struct watchdog_device *wdog) | |
72 | { | |
73 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
74 | ||
75 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); | |
76 | ||
77 | return 0; | |
78 | } | |
79 | ||
80 | static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) | |
81 | { | |
82 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
83 | ||
84 | dc_wdt_set(wdt, t * clk_get_rate(wdt->clk)); | |
85 | wdog->timeout = t; | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
90 | static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog) | |
91 | { | |
92 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
93 | uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT); | |
94 | ||
95 | return count / clk_get_rate(wdt->clk); | |
96 | } | |
97 | ||
98 | static struct watchdog_ops dc_wdt_ops = { | |
99 | .owner = THIS_MODULE, | |
100 | .start = dc_wdt_start, | |
101 | .stop = dc_wdt_stop, | |
102 | .set_timeout = dc_wdt_set_timeout, | |
103 | .get_timeleft = dc_wdt_get_timeleft, | |
d3b08185 | 104 | .restart = dc_wdt_restart, |
336694a0 BS |
105 | }; |
106 | ||
107 | static struct watchdog_info dc_wdt_info = { | |
108 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | |
109 | | WDIOF_KEEPALIVEPING, | |
110 | .identity = "Conexant Digicolor Watchdog", | |
111 | }; | |
112 | ||
113 | static struct watchdog_device dc_wdt_wdd = { | |
114 | .info = &dc_wdt_info, | |
115 | .ops = &dc_wdt_ops, | |
116 | .min_timeout = 1, | |
117 | }; | |
118 | ||
119 | static int dc_wdt_probe(struct platform_device *pdev) | |
120 | { | |
121 | struct device *dev = &pdev->dev; | |
122 | struct device_node *np = dev->of_node; | |
123 | struct dc_wdt *wdt; | |
124 | int ret; | |
125 | ||
126 | wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL); | |
127 | if (!wdt) | |
128 | return -ENOMEM; | |
129 | platform_set_drvdata(pdev, wdt); | |
130 | ||
131 | wdt->base = of_iomap(np, 0); | |
132 | if (!wdt->base) { | |
133 | dev_err(dev, "Failed to remap watchdog regs"); | |
134 | return -ENODEV; | |
135 | } | |
136 | ||
137 | wdt->clk = devm_clk_get(&pdev->dev, NULL); | |
138 | if (IS_ERR(wdt->clk)) { | |
139 | ret = PTR_ERR(wdt->clk); | |
140 | goto err_iounmap; | |
141 | } | |
142 | dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk); | |
143 | dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout; | |
6551881c | 144 | dc_wdt_wdd.parent = &pdev->dev; |
336694a0 BS |
145 | |
146 | spin_lock_init(&wdt->lock); | |
147 | ||
148 | watchdog_set_drvdata(&dc_wdt_wdd, wdt); | |
d3b08185 | 149 | watchdog_set_restart_priority(&dc_wdt_wdd, 128); |
336694a0 BS |
150 | watchdog_init_timeout(&dc_wdt_wdd, timeout, dev); |
151 | ret = watchdog_register_device(&dc_wdt_wdd); | |
152 | if (ret) { | |
153 | dev_err(dev, "Failed to register watchdog device"); | |
154 | goto err_iounmap; | |
155 | } | |
156 | ||
336694a0 BS |
157 | return 0; |
158 | ||
159 | err_iounmap: | |
160 | iounmap(wdt->base); | |
161 | return ret; | |
162 | } | |
163 | ||
164 | static int dc_wdt_remove(struct platform_device *pdev) | |
165 | { | |
166 | struct dc_wdt *wdt = platform_get_drvdata(pdev); | |
167 | ||
336694a0 BS |
168 | watchdog_unregister_device(&dc_wdt_wdd); |
169 | iounmap(wdt->base); | |
170 | ||
171 | return 0; | |
172 | } | |
173 | ||
174 | static void dc_wdt_shutdown(struct platform_device *pdev) | |
175 | { | |
176 | dc_wdt_stop(&dc_wdt_wdd); | |
177 | } | |
178 | ||
179 | static const struct of_device_id dc_wdt_of_match[] = { | |
180 | { .compatible = "cnxt,cx92755-wdt", }, | |
181 | {}, | |
182 | }; | |
183 | MODULE_DEVICE_TABLE(of, dc_wdt_of_match); | |
184 | ||
185 | static struct platform_driver dc_wdt_driver = { | |
186 | .probe = dc_wdt_probe, | |
187 | .remove = dc_wdt_remove, | |
188 | .shutdown = dc_wdt_shutdown, | |
189 | .driver = { | |
190 | .name = "digicolor-wdt", | |
191 | .of_match_table = dc_wdt_of_match, | |
192 | }, | |
193 | }; | |
194 | module_platform_driver(dc_wdt_driver); | |
195 | ||
196 | MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); | |
197 | MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer"); | |
198 | MODULE_LICENSE("GPL"); |