1 /*
2 * Copyright © 2014-2017 Broadcom
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16 #include <linux/clk.h>
17 #include <linux/device.h>
18 #include <linux/err.h>
19 #include <linux/init.h>
20 #include <linux/interrupt.h>
21 #include <linux/io.h>
22 #include <linux/irqreturn.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/of.h>
26 #include <linux/platform_device.h>
27 #include <linux/pm.h>
28 #include <linux/pm_wakeup.h>
29 #include <linux/reboot.h>
30 #include <linux/rtc.h>
31 #include <linux/stat.h>
32 #include <linux/suspend.h>
33
34 struct brcmstb_waketmr {
35 struct rtc_device *rtc;
36 struct device *dev;
37 void __iomem *base;
38 int irq;
39 struct notifier_block reboot_notifier;
40 struct clk *clk;
41 u32 rate;
42 };
43
44 #define BRCMSTB_WKTMR_EVENT 0x00
45 #define BRCMSTB_WKTMR_COUNTER 0x04
46 #define BRCMSTB_WKTMR_ALARM 0x08
47 #define BRCMSTB_WKTMR_PRESCALER 0x0C
48 #define BRCMSTB_WKTMR_PRESCALER_VAL 0x10
49
50 #define BRCMSTB_WKTMR_DEFAULT_FREQ 27000000
51
brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr * timer)52 static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer)
53 {
54 writel_relaxed(1, timer->base + BRCMSTB_WKTMR_EVENT);
55 (void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
56 }
57
brcmstb_waketmr_set_alarm(struct brcmstb_waketmr * timer,unsigned int secs)58 static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
59 unsigned int secs)
60 {
61 brcmstb_waketmr_clear_alarm(timer);
62
63 /* Make sure we are actually counting in seconds */
64 writel_relaxed(timer->rate, timer->base + BRCMSTB_WKTMR_PRESCALER);
65
66 writel_relaxed(secs + 1, timer->base + BRCMSTB_WKTMR_ALARM);
67 }
68
brcmstb_waketmr_irq(int irq,void * data)69 static irqreturn_t brcmstb_waketmr_irq(int irq, void *data)
70 {
71 struct brcmstb_waketmr *timer = data;
72
73 pm_wakeup_event(timer->dev, 0);
74
75 return IRQ_HANDLED;
76 }
77
78 struct wktmr_time {
79 u32 sec;
80 u32 pre;
81 };
82
wktmr_read(struct brcmstb_waketmr * timer,struct wktmr_time * t)83 static void wktmr_read(struct brcmstb_waketmr *timer,
84 struct wktmr_time *t)
85 {
86 u32 tmp;
87
88 do {
89 t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
90 tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL);
91 } while (tmp >= timer->rate);
92
93 t->pre = timer->rate - tmp;
94 }
95
brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr * timer)96 static int brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr *timer)
97 {
98 struct device *dev = timer->dev;
99 int ret = 0;
100
101 if (device_may_wakeup(dev)) {
102 ret = enable_irq_wake(timer->irq);
103 if (ret) {
104 dev_err(dev, "failed to enable wake-up interrupt\n");
105 return ret;
106 }
107 }
108
109 return ret;
110 }
111
112 /* If enabled as a wakeup-source, arm the timer when powering off */
brcmstb_waketmr_reboot(struct notifier_block * nb,unsigned long action,void * data)113 static int brcmstb_waketmr_reboot(struct notifier_block *nb,
114 unsigned long action, void *data)
115 {
116 struct brcmstb_waketmr *timer;
117
118 timer = container_of(nb, struct brcmstb_waketmr, reboot_notifier);
119
120 /* Set timer for cold boot */
121 if (action == SYS_POWER_OFF)
122 brcmstb_waketmr_prepare_suspend(timer);
123
124 return NOTIFY_DONE;
125 }
126
brcmstb_waketmr_gettime(struct device * dev,struct rtc_time * tm)127 static int brcmstb_waketmr_gettime(struct device *dev,
128 struct rtc_time *tm)
129 {
130 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
131 struct wktmr_time now;
132
133 wktmr_read(timer, &now);
134
135 rtc_time_to_tm(now.sec, tm);
136
137 return 0;
138 }
139
brcmstb_waketmr_settime(struct device * dev,struct rtc_time * tm)140 static int brcmstb_waketmr_settime(struct device *dev,
141 struct rtc_time *tm)
142 {
143 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
144 time64_t sec;
145
146 sec = rtc_tm_to_time64(tm);
147
148 writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER);
149
150 return 0;
151 }
152
brcmstb_waketmr_getalarm(struct device * dev,struct rtc_wkalrm * alarm)153 static int brcmstb_waketmr_getalarm(struct device *dev,
154 struct rtc_wkalrm *alarm)
155 {
156 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
157 time64_t sec;
158 u32 reg;
159
160 sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM);
161 if (sec != 0) {
162 /* Alarm is enabled */
163 alarm->enabled = 1;
164 rtc_time64_to_tm(sec, &alarm->time);
165 }
166
167 reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
168 alarm->pending = !!(reg & 1);
169
170 return 0;
171 }
172
brcmstb_waketmr_setalarm(struct device * dev,struct rtc_wkalrm * alarm)173 static int brcmstb_waketmr_setalarm(struct device *dev,
174 struct rtc_wkalrm *alarm)
175 {
176 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
177 time64_t sec;
178
179 if (alarm->enabled)
180 sec = rtc_tm_to_time64(&alarm->time);
181 else
182 sec = 0;
183
184 brcmstb_waketmr_set_alarm(timer, sec);
185
186 return 0;
187 }
188
189 /*
190 * Does not do much but keep the RTC class happy. We always support
191 * alarms.
192 */
brcmstb_waketmr_alarm_enable(struct device * dev,unsigned int enabled)193 static int brcmstb_waketmr_alarm_enable(struct device *dev,
194 unsigned int enabled)
195 {
196 return 0;
197 }
198
199 static const struct rtc_class_ops brcmstb_waketmr_ops = {
200 .read_time = brcmstb_waketmr_gettime,
201 .set_time = brcmstb_waketmr_settime,
202 .read_alarm = brcmstb_waketmr_getalarm,
203 .set_alarm = brcmstb_waketmr_setalarm,
204 .alarm_irq_enable = brcmstb_waketmr_alarm_enable,
205 };
206
brcmstb_waketmr_probe(struct platform_device * pdev)207 static int brcmstb_waketmr_probe(struct platform_device *pdev)
208 {
209 struct device *dev = &pdev->dev;
210 struct brcmstb_waketmr *timer;
211 struct resource *res;
212 int ret;
213
214 timer = devm_kzalloc(dev, sizeof(*timer), GFP_KERNEL);
215 if (!timer)
216 return -ENOMEM;
217
218 platform_set_drvdata(pdev, timer);
219 timer->dev = dev;
220
221 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
222 timer->base = devm_ioremap_resource(dev, res);
223 if (IS_ERR(timer->base))
224 return PTR_ERR(timer->base);
225
226 timer->rtc = devm_rtc_allocate_device(dev);
227 if (IS_ERR(timer->rtc))
228 return PTR_ERR(timer->rtc);
229
230 /*
231 * Set wakeup capability before requesting wakeup interrupt, so we can
232 * process boot-time "wakeups" (e.g., from S5 soft-off)
233 */
234 device_set_wakeup_capable(dev, true);
235 device_wakeup_enable(dev);
236
237 timer->irq = platform_get_irq(pdev, 0);
238 if (timer->irq < 0)
239 return -ENODEV;
240
241 timer->clk = devm_clk_get(dev, NULL);
242 if (!IS_ERR(timer->clk)) {
243 ret = clk_prepare_enable(timer->clk);
244 if (ret)
245 return ret;
246 timer->rate = clk_get_rate(timer->clk);
247 if (!timer->rate)
248 timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
249 } else {
250 timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
251 timer->clk = NULL;
252 }
253
254 ret = devm_request_irq(dev, timer->irq, brcmstb_waketmr_irq, 0,
255 "brcmstb-waketimer", timer);
256 if (ret < 0)
257 goto err_clk;
258
259 timer->reboot_notifier.notifier_call = brcmstb_waketmr_reboot;
260 register_reboot_notifier(&timer->reboot_notifier);
261
262 timer->rtc->ops = &brcmstb_waketmr_ops;
263 timer->rtc->range_max = U32_MAX;
264
265 ret = rtc_register_device(timer->rtc);
266 if (ret) {
267 dev_err(dev, "unable to register device\n");
268 goto err_notifier;
269 }
270
271 dev_info(dev, "registered, with irq %d\n", timer->irq);
272
273 return 0;
274
275 err_notifier:
276 unregister_reboot_notifier(&timer->reboot_notifier);
277
278 err_clk:
279 if (timer->clk)
280 clk_disable_unprepare(timer->clk);
281
282 return ret;
283 }
284
brcmstb_waketmr_remove(struct platform_device * pdev)285 static int brcmstb_waketmr_remove(struct platform_device *pdev)
286 {
287 struct brcmstb_waketmr *timer = dev_get_drvdata(&pdev->dev);
288
289 unregister_reboot_notifier(&timer->reboot_notifier);
290
291 return 0;
292 }
293
294 #ifdef CONFIG_PM_SLEEP
brcmstb_waketmr_suspend(struct device * dev)295 static int brcmstb_waketmr_suspend(struct device *dev)
296 {
297 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
298
299 return brcmstb_waketmr_prepare_suspend(timer);
300 }
301
brcmstb_waketmr_resume(struct device * dev)302 static int brcmstb_waketmr_resume(struct device *dev)
303 {
304 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
305 int ret;
306
307 if (!device_may_wakeup(dev))
308 return 0;
309
310 ret = disable_irq_wake(timer->irq);
311
312 brcmstb_waketmr_clear_alarm(timer);
313
314 return ret;
315 }
316 #endif /* CONFIG_PM_SLEEP */
317
318 static SIMPLE_DEV_PM_OPS(brcmstb_waketmr_pm_ops,
319 brcmstb_waketmr_suspend, brcmstb_waketmr_resume);
320
321 static const struct of_device_id brcmstb_waketmr_of_match[] = {
322 { .compatible = "brcm,brcmstb-waketimer" },
323 { /* sentinel */ },
324 };
325
326 static struct platform_driver brcmstb_waketmr_driver = {
327 .probe = brcmstb_waketmr_probe,
328 .remove = brcmstb_waketmr_remove,
329 .driver = {
330 .name = "brcmstb-waketimer",
331 .pm = &brcmstb_waketmr_pm_ops,
332 .of_match_table = of_match_ptr(brcmstb_waketmr_of_match),
333 }
334 };
335 module_platform_driver(brcmstb_waketmr_driver);
336
337 MODULE_LICENSE("GPL v2");
338 MODULE_AUTHOR("Brian Norris");
339 MODULE_AUTHOR("Markus Mayer");
340 MODULE_DESCRIPTION("Wake-up timer driver for STB chips");
341
