1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * Watchdog driver for Conexant Digicolor |
4 | * |
5 | * Copyright (C) 2015 Paradox Innovation Ltd. |
6 | * |
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> |
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; |
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(lock: &wdt->lock, flags); |
46 | } |
47 | |
48 | static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action, |
49 | void *data) |
50 | { |
51 | struct dc_wdt *wdt = watchdog_get_drvdata(wdd: wdog); |
52 | |
53 | dc_wdt_set(wdt, ticks: 1); |
54 | /* wait for reset to assert... */ |
55 | mdelay(500); |
56 | |
57 | return 0; |
58 | } |
59 | |
60 | static int dc_wdt_start(struct watchdog_device *wdog) |
61 | { |
62 | struct dc_wdt *wdt = watchdog_get_drvdata(wdd: wdog); |
63 | |
64 | dc_wdt_set(wdt, ticks: wdog->timeout * clk_get_rate(clk: 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(wdd: 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(wdd: wdog); |
81 | |
82 | dc_wdt_set(wdt, ticks: t * clk_get_rate(clk: 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(wdd: wdog); |
91 | uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT); |
92 | |
93 | return count / clk_get_rate(clk: wdt->clk); |
94 | } |
95 | |
96 | static const struct watchdog_ops dc_wdt_ops = { |
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, |
102 | .restart = dc_wdt_restart, |
103 | }; |
104 | |
105 | static const struct watchdog_info dc_wdt_info = { |
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 | { |
119 | struct device *dev = &pdev->dev; |
120 | struct dc_wdt *wdt; |
121 | |
122 | wdt = devm_kzalloc(dev, size: sizeof(struct dc_wdt), GFP_KERNEL); |
123 | if (!wdt) |
124 | return -ENOMEM; |
125 | |
126 | wdt->base = devm_platform_ioremap_resource(pdev, index: 0); |
127 | if (IS_ERR(ptr: wdt->base)) |
128 | return PTR_ERR(ptr: wdt->base); |
129 | |
130 | wdt->clk = devm_clk_get(dev, NULL); |
131 | if (IS_ERR(ptr: wdt->clk)) |
132 | return PTR_ERR(ptr: wdt->clk); |
133 | dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(clk: wdt->clk); |
134 | dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout; |
135 | dc_wdt_wdd.parent = dev; |
136 | |
137 | spin_lock_init(&wdt->lock); |
138 | |
139 | watchdog_set_drvdata(wdd: &dc_wdt_wdd, data: wdt); |
140 | watchdog_set_restart_priority(wdd: &dc_wdt_wdd, priority: 128); |
141 | watchdog_init_timeout(wdd: &dc_wdt_wdd, timeout_parm: timeout, dev); |
142 | watchdog_stop_on_reboot(wdd: &dc_wdt_wdd); |
143 | return devm_watchdog_register_device(dev, &dc_wdt_wdd); |
144 | } |
145 | |
146 | static const struct of_device_id dc_wdt_of_match[] = { |
147 | { .compatible = "cnxt,cx92755-wdt" , }, |
148 | {}, |
149 | }; |
150 | MODULE_DEVICE_TABLE(of, dc_wdt_of_match); |
151 | |
152 | static struct platform_driver dc_wdt_driver = { |
153 | .probe = dc_wdt_probe, |
154 | .driver = { |
155 | .name = "digicolor-wdt" , |
156 | .of_match_table = dc_wdt_of_match, |
157 | }, |
158 | }; |
159 | module_platform_driver(dc_wdt_driver); |
160 | |
161 | MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>" ); |
162 | MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer" ); |
163 | MODULE_LICENSE("GPL" ); |
164 | |