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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>
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
27struct dc_wdt {
28 void __iomem *base;
29 struct clk *clk;
30 spinlock_t lock;
31};
32
33static unsigned timeout;
34module_param(timeout, uint, 0);
35MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
36
37static 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
51static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action,
52 void *data)
53{
54 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
55
56 dc_wdt_set(wdt, 1);
57
58 mdelay(500);
59
60 return 0;
61}
62
63static 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
72static 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
81static 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
91static 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
99static struct watchdog_ops dc_wdt_ops = {
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,
105 .restart = dc_wdt_restart,
106};
107
108static struct watchdog_info dc_wdt_info = {
109 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
110 | WDIOF_KEEPALIVEPING,
111 .identity = "Conexant Digicolor Watchdog",
112};
113
114static struct watchdog_device dc_wdt_wdd = {
115 .info = &dc_wdt_info,
116 .ops = &dc_wdt_ops,
117 .min_timeout = 1,
118};
119
120static int dc_wdt_probe(struct platform_device *pdev)
121{
122 struct device *dev = &pdev->dev;
123 struct device_node *np = dev->of_node;
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;
130 platform_set_drvdata(pdev, wdt);
131
132 wdt->base = of_iomap(np, 0);
133 if (!wdt->base) {
134 dev_err(dev, "Failed to remap watchdog regs");
135 return -ENODEV;
136 }
137
138 wdt->clk = devm_clk_get(&pdev->dev, NULL);
139 if (IS_ERR(wdt->clk)) {
140 ret = PTR_ERR(wdt->clk);
141 goto err_iounmap;
142 }
143 dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
144 dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
145 dc_wdt_wdd.parent = &pdev->dev;
146
147 spin_lock_init(&wdt->lock);
148
149 watchdog_set_drvdata(&dc_wdt_wdd, wdt);
150 watchdog_set_restart_priority(&dc_wdt_wdd, 128);
151 watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
152 ret = watchdog_register_device(&dc_wdt_wdd);
153 if (ret) {
154 dev_err(dev, "Failed to register watchdog device");
155 goto err_iounmap;
156 }
157
158 return 0;
159
160err_iounmap:
161 iounmap(wdt->base);
162 return ret;
163}
164
165static int dc_wdt_remove(struct platform_device *pdev)
166{
167 struct dc_wdt *wdt = platform_get_drvdata(pdev);
168
169 watchdog_unregister_device(&dc_wdt_wdd);
170 iounmap(wdt->base);
171
172 return 0;
173}
174
175static void dc_wdt_shutdown(struct platform_device *pdev)
176{
177 dc_wdt_stop(&dc_wdt_wdd);
178}
179
180static const struct of_device_id dc_wdt_of_match[] = {
181 { .compatible = "cnxt,cx92755-wdt", },
182 {},
183};
184MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
185
186static struct platform_driver dc_wdt_driver = {
187 .probe = dc_wdt_probe,
188 .remove = dc_wdt_remove,
189 .shutdown = dc_wdt_shutdown,
190 .driver = {
191 .name = "digicolor-wdt",
192 .of_match_table = dc_wdt_of_match,
193 },
194};
195module_platform_driver(dc_wdt_driver);
196
197MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
198MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
199MODULE_LICENSE("GPL");
200
