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15#include <linux/clk.h>
16#include <linux/init.h>
17#include <linux/io.h>
18#include <linux/kernel.h>
19#include <linux/mfd/syscon.h>
20#include <linux/module.h>
21#include <linux/of.h>
22#include <linux/of_platform.h>
23#include <linux/platform_device.h>
24#include <linux/regmap.h>
25#include <linux/watchdog.h>
26
27#include <dt-bindings/mfd/st-lpc.h>
28
29
30#define LPC_LPA_LSB_OFF 0x410
31#define LPC_LPA_START_OFF 0x418
32
33
34#define LPC_WDT_OFF 0x510
35
36static struct watchdog_device st_wdog_dev;
37
38struct st_wdog_syscfg {
39 unsigned int reset_type_reg;
40 unsigned int reset_type_mask;
41 unsigned int enable_reg;
42 unsigned int enable_mask;
43};
44
45struct st_wdog {
46 void __iomem *base;
47 struct device *dev;
48 struct regmap *regmap;
49 struct st_wdog_syscfg *syscfg;
50 struct clk *clk;
51 unsigned long clkrate;
52 bool warm_reset;
53};
54
55static struct st_wdog_syscfg stih407_syscfg = {
56 .enable_reg = 0x204,
57 .enable_mask = BIT(19),
58};
59
60static const struct of_device_id st_wdog_match[] = {
61 {
62 .compatible = "st,stih407-lpc",
63 .data = &stih407_syscfg,
64 },
65 {},
66};
67MODULE_DEVICE_TABLE(of, st_wdog_match);
68
69static void st_wdog_setup(struct st_wdog *st_wdog, bool enable)
70{
71
72 if (st_wdog->syscfg->reset_type_reg)
73 regmap_update_bits(st_wdog->regmap,
74 st_wdog->syscfg->reset_type_reg,
75 st_wdog->syscfg->reset_type_mask,
76 st_wdog->warm_reset);
77
78
79 regmap_update_bits(st_wdog->regmap,
80 st_wdog->syscfg->enable_reg,
81 st_wdog->syscfg->enable_mask,
82 enable ? 0 : st_wdog->syscfg->enable_mask);
83}
84
85static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout)
86{
87 unsigned long clkrate = st_wdog->clkrate;
88
89 writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF);
90 writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF);
91}
92
93static int st_wdog_start(struct watchdog_device *wdd)
94{
95 struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
96
97 writel_relaxed(1, st_wdog->base + LPC_WDT_OFF);
98
99 return 0;
100}
101
102static int st_wdog_stop(struct watchdog_device *wdd)
103{
104 struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
105
106 writel_relaxed(0, st_wdog->base + LPC_WDT_OFF);
107
108 return 0;
109}
110
111static int st_wdog_set_timeout(struct watchdog_device *wdd,
112 unsigned int timeout)
113{
114 struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
115
116 wdd->timeout = timeout;
117 st_wdog_load_timer(st_wdog, timeout);
118
119 return 0;
120}
121
122static int st_wdog_keepalive(struct watchdog_device *wdd)
123{
124 struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
125
126 st_wdog_load_timer(st_wdog, wdd->timeout);
127
128 return 0;
129}
130
131static const struct watchdog_info st_wdog_info = {
132 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
133 .identity = "ST LPC WDT",
134};
135
136static const struct watchdog_ops st_wdog_ops = {
137 .owner = THIS_MODULE,
138 .start = st_wdog_start,
139 .stop = st_wdog_stop,
140 .ping = st_wdog_keepalive,
141 .set_timeout = st_wdog_set_timeout,
142};
143
144static struct watchdog_device st_wdog_dev = {
145 .info = &st_wdog_info,
146 .ops = &st_wdog_ops,
147};
148
149static int st_wdog_probe(struct platform_device *pdev)
150{
151 const struct of_device_id *match;
152 struct device_node *np = pdev->dev.of_node;
153 struct st_wdog *st_wdog;
154 struct regmap *regmap;
155 struct resource *res;
156 struct clk *clk;
157 void __iomem *base;
158 uint32_t mode;
159 int ret;
160
161 ret = of_property_read_u32(np, "st,lpc-mode", &mode);
162 if (ret) {
163 dev_err(&pdev->dev, "An LPC mode must be provided\n");
164 return -EINVAL;
165 }
166
167
168 if (mode != ST_LPC_MODE_WDT)
169 return -ENODEV;
170
171 st_wdog = devm_kzalloc(&pdev->dev, sizeof(*st_wdog), GFP_KERNEL);
172 if (!st_wdog)
173 return -ENOMEM;
174
175 match = of_match_device(st_wdog_match, &pdev->dev);
176 if (!match) {
177 dev_err(&pdev->dev, "Couldn't match device\n");
178 return -ENODEV;
179 }
180 st_wdog->syscfg = (struct st_wdog_syscfg *)match->data;
181
182 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
183 base = devm_ioremap_resource(&pdev->dev, res);
184 if (IS_ERR(base))
185 return PTR_ERR(base);
186
187 regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
188 if (IS_ERR(regmap)) {
189 dev_err(&pdev->dev, "No syscfg phandle specified\n");
190 return PTR_ERR(regmap);
191 }
192
193 clk = devm_clk_get(&pdev->dev, NULL);
194 if (IS_ERR(clk)) {
195 dev_err(&pdev->dev, "Unable to request clock\n");
196 return PTR_ERR(clk);
197 }
198
199 st_wdog->dev = &pdev->dev;
200 st_wdog->base = base;
201 st_wdog->clk = clk;
202 st_wdog->regmap = regmap;
203 st_wdog->warm_reset = of_property_read_bool(np, "st,warm_reset");
204 st_wdog->clkrate = clk_get_rate(st_wdog->clk);
205
206 if (!st_wdog->clkrate) {
207 dev_err(&pdev->dev, "Unable to fetch clock rate\n");
208 return -EINVAL;
209 }
210 st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate;
211 st_wdog_dev.parent = &pdev->dev;
212
213 ret = clk_prepare_enable(clk);
214 if (ret) {
215 dev_err(&pdev->dev, "Unable to enable clock\n");
216 return ret;
217 }
218
219 watchdog_set_drvdata(&st_wdog_dev, st_wdog);
220 watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT);
221
222
223 ret = watchdog_init_timeout(&st_wdog_dev, 0, &pdev->dev);
224 if (ret) {
225 dev_err(&pdev->dev, "Unable to initialise watchdog timeout\n");
226 clk_disable_unprepare(clk);
227 return ret;
228 }
229
230 ret = watchdog_register_device(&st_wdog_dev);
231 if (ret) {
232 dev_err(&pdev->dev, "Unable to register watchdog\n");
233 clk_disable_unprepare(clk);
234 return ret;
235 }
236
237 st_wdog_setup(st_wdog, true);
238
239 dev_info(&pdev->dev, "LPC Watchdog driver registered, reset type is %s",
240 st_wdog->warm_reset ? "warm" : "cold");
241
242 return ret;
243}
244
245static int st_wdog_remove(struct platform_device *pdev)
246{
247 struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
248
249 st_wdog_setup(st_wdog, false);
250 watchdog_unregister_device(&st_wdog_dev);
251 clk_disable_unprepare(st_wdog->clk);
252
253 return 0;
254}
255
256#ifdef CONFIG_PM_SLEEP
257static int st_wdog_suspend(struct device *dev)
258{
259 struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
260
261 if (watchdog_active(&st_wdog_dev))
262 st_wdog_stop(&st_wdog_dev);
263
264 st_wdog_setup(st_wdog, false);
265
266 clk_disable(st_wdog->clk);
267
268 return 0;
269}
270
271static int st_wdog_resume(struct device *dev)
272{
273 struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
274 int ret;
275
276 ret = clk_enable(st_wdog->clk);
277 if (ret) {
278 dev_err(dev, "Unable to re-enable clock\n");
279 watchdog_unregister_device(&st_wdog_dev);
280 clk_unprepare(st_wdog->clk);
281 return ret;
282 }
283
284 st_wdog_setup(st_wdog, true);
285
286 if (watchdog_active(&st_wdog_dev)) {
287 st_wdog_load_timer(st_wdog, st_wdog_dev.timeout);
288 st_wdog_start(&st_wdog_dev);
289 }
290
291 return 0;
292}
293#endif
294
295static SIMPLE_DEV_PM_OPS(st_wdog_pm_ops,
296 st_wdog_suspend,
297 st_wdog_resume);
298
299static struct platform_driver st_wdog_driver = {
300 .driver = {
301 .name = "st-lpc-wdt",
302 .pm = &st_wdog_pm_ops,
303 .of_match_table = st_wdog_match,
304 },
305 .probe = st_wdog_probe,
306 .remove = st_wdog_remove,
307};
308module_platform_driver(st_wdog_driver);
309
310MODULE_AUTHOR("David Paris <david.paris@st.com>");
311MODULE_DESCRIPTION("ST LPC Watchdog Driver");
312MODULE_LICENSE("GPL");
313
