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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
24struct dc_wdt {
25 void __iomem *base;
26 struct clk *clk;
27 spinlock_t lock;
28};
29
30static unsigned timeout;
31module_param(timeout, uint, 0);
32MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
33
34static 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
48static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action,
49 void *data)
50{
51 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
52
53 dc_wdt_set(wdt, 1);
54
55 mdelay(500);
56
57 return 0;
58}
59
60static 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
69static 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
78static 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
88static 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
96static 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
105static const struct watchdog_info dc_wdt_info = {
106 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
107 | WDIOF_KEEPALIVEPING,
108 .identity = "Conexant Digicolor Watchdog",
109};
110
111static struct watchdog_device dc_wdt_wdd = {
112 .info = &dc_wdt_info,
113 .ops = &dc_wdt_ops,
114 .min_timeout = 1,
115};
116
117static 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, sizeof(struct dc_wdt), GFP_KERNEL);
123 if (!wdt)
124 return -ENOMEM;
125
126 wdt->base = devm_platform_ioremap_resource(pdev, 0);
127 if (IS_ERR(wdt->base))
128 return PTR_ERR(wdt->base);
129
130 wdt->clk = devm_clk_get(dev, NULL);
131 if (IS_ERR(wdt->clk))
132 return PTR_ERR(wdt->clk);
133 dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(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(&dc_wdt_wdd, wdt);
140 watchdog_set_restart_priority(&dc_wdt_wdd, 128);
141 watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
142 watchdog_stop_on_reboot(&dc_wdt_wdd);
143 return devm_watchdog_register_device(dev, &dc_wdt_wdd);
144}
145
146static const struct of_device_id dc_wdt_of_match[] = {
147 { .compatible = "cnxt,cx92755-wdt", },
148 {},
149};
150MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
151
152static 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};
159module_platform_driver(dc_wdt_driver);
160
161MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
162MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
163MODULE_LICENSE("GPL");
164
