1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright © 2014-2017 Broadcom
4 */
5
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8 #include <linux/clk.h>
9 #include <linux/device.h>
10 #include <linux/err.h>
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/irqreturn.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/platform_device.h>
19 #include <linux/pm.h>
20 #include <linux/pm_wakeup.h>
21 #include <linux/reboot.h>
22 #include <linux/rtc.h>
23 #include <linux/stat.h>
24 #include <linux/suspend.h>
25
26 struct brcmstb_waketmr {
27 struct rtc_device *rtc;
28 struct device *dev;
29 void __iomem *base;
30 unsigned int wake_irq;
31 unsigned int alarm_irq;
32 struct notifier_block reboot_notifier;
33 struct clk *clk;
34 u32 rate;
35 unsigned long rtc_alarm;
36 bool alarm_en;
37 };
38
39 #define BRCMSTB_WKTMR_EVENT 0x00
40 #define WKTMR_ALARM_EVENT BIT(0)
41 #define BRCMSTB_WKTMR_COUNTER 0x04
42 #define BRCMSTB_WKTMR_ALARM 0x08
43 #define BRCMSTB_WKTMR_PRESCALER 0x0C
44 #define BRCMSTB_WKTMR_PRESCALER_VAL 0x10
45
46 #define BRCMSTB_WKTMR_DEFAULT_FREQ 27000000
47
brcmstb_waketmr_is_pending(struct brcmstb_waketmr * timer)48 static inline bool brcmstb_waketmr_is_pending(struct brcmstb_waketmr *timer)
49 {
50 u32 reg;
51
52 reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
53 return !!(reg & WKTMR_ALARM_EVENT);
54 }
55
brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr * timer)56 static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer)
57 {
58 u32 reg;
59
60 if (timer->alarm_en && timer->alarm_irq)
61 disable_irq(timer->alarm_irq);
62 timer->alarm_en = false;
63 reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
64 writel_relaxed(reg - 1, timer->base + BRCMSTB_WKTMR_ALARM);
65 writel_relaxed(WKTMR_ALARM_EVENT, timer->base + BRCMSTB_WKTMR_EVENT);
66 (void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
67 }
68
brcmstb_waketmr_set_alarm(struct brcmstb_waketmr * timer,unsigned int secs)69 static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
70 unsigned int secs)
71 {
72 unsigned int now;
73
74 brcmstb_waketmr_clear_alarm(timer);
75
76 /* Make sure we are actually counting in seconds */
77 writel_relaxed(timer->rate, timer->base + BRCMSTB_WKTMR_PRESCALER);
78
79 writel_relaxed(secs, timer->base + BRCMSTB_WKTMR_ALARM);
80 now = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
81
82 while ((int)(secs - now) <= 0 &&
83 !brcmstb_waketmr_is_pending(timer)) {
84 secs = now + 1;
85 writel_relaxed(secs, timer->base + BRCMSTB_WKTMR_ALARM);
86 now = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
87 }
88 }
89
brcmstb_waketmr_irq(int irq,void * data)90 static irqreturn_t brcmstb_waketmr_irq(int irq, void *data)
91 {
92 struct brcmstb_waketmr *timer = data;
93
94 if (!timer->alarm_irq)
95 pm_wakeup_event(timer->dev, 0);
96 return IRQ_HANDLED;
97 }
98
brcmstb_alarm_irq(int irq,void * data)99 static irqreturn_t brcmstb_alarm_irq(int irq, void *data)
100 {
101 struct brcmstb_waketmr *timer = data;
102
103 /* Ignore spurious interrupts */
104 if (!brcmstb_waketmr_is_pending(timer))
105 return IRQ_HANDLED;
106
107 if (timer->alarm_en) {
108 if (!device_may_wakeup(timer->dev))
109 writel_relaxed(WKTMR_ALARM_EVENT,
110 timer->base + BRCMSTB_WKTMR_EVENT);
111 rtc_update_irq(timer->rtc, 1, RTC_IRQF | RTC_AF);
112 }
113
114 return IRQ_HANDLED;
115 }
116
117 struct wktmr_time {
118 u32 sec;
119 u32 pre;
120 };
121
wktmr_read(struct brcmstb_waketmr * timer,struct wktmr_time * t)122 static void wktmr_read(struct brcmstb_waketmr *timer,
123 struct wktmr_time *t)
124 {
125 u32 tmp;
126
127 do {
128 t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
129 tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL);
130 } while (tmp >= timer->rate);
131
132 t->pre = timer->rate - tmp;
133 }
134
brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr * timer)135 static int brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr *timer)
136 {
137 struct device *dev = timer->dev;
138 int ret;
139
140 if (device_may_wakeup(dev)) {
141 ret = enable_irq_wake(timer->wake_irq);
142 if (ret) {
143 dev_err(dev, "failed to enable wake-up interrupt\n");
144 return ret;
145 }
146 if (timer->alarm_en && timer->alarm_irq) {
147 ret = enable_irq_wake(timer->alarm_irq);
148 if (ret) {
149 dev_err(dev, "failed to enable rtc interrupt\n");
150 disable_irq_wake(timer->wake_irq);
151 return ret;
152 }
153 }
154 }
155
156 return 0;
157 }
158
159 /* If enabled as a wakeup-source, arm the timer when powering off */
brcmstb_waketmr_reboot(struct notifier_block * nb,unsigned long action,void * data)160 static int brcmstb_waketmr_reboot(struct notifier_block *nb,
161 unsigned long action, void *data)
162 {
163 struct brcmstb_waketmr *timer;
164
165 timer = container_of(nb, struct brcmstb_waketmr, reboot_notifier);
166
167 /* Set timer for cold boot */
168 if (action == SYS_POWER_OFF)
169 brcmstb_waketmr_prepare_suspend(timer);
170
171 return NOTIFY_DONE;
172 }
173
brcmstb_waketmr_gettime(struct device * dev,struct rtc_time * tm)174 static int brcmstb_waketmr_gettime(struct device *dev,
175 struct rtc_time *tm)
176 {
177 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
178 struct wktmr_time now;
179
180 wktmr_read(timer, &now);
181
182 rtc_time64_to_tm(now.sec, tm);
183
184 return 0;
185 }
186
brcmstb_waketmr_settime(struct device * dev,struct rtc_time * tm)187 static int brcmstb_waketmr_settime(struct device *dev,
188 struct rtc_time *tm)
189 {
190 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
191 time64_t sec;
192
193 sec = rtc_tm_to_time64(tm);
194
195 writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER);
196
197 return 0;
198 }
199
brcmstb_waketmr_getalarm(struct device * dev,struct rtc_wkalrm * alarm)200 static int brcmstb_waketmr_getalarm(struct device *dev,
201 struct rtc_wkalrm *alarm)
202 {
203 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
204
205 alarm->enabled = timer->alarm_en;
206 rtc_time64_to_tm(timer->rtc_alarm, &alarm->time);
207
208 alarm->pending = brcmstb_waketmr_is_pending(timer);
209
210 return 0;
211 }
212
brcmstb_waketmr_alarm_enable(struct device * dev,unsigned int enabled)213 static int brcmstb_waketmr_alarm_enable(struct device *dev,
214 unsigned int enabled)
215 {
216 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
217
218 if (enabled && !timer->alarm_en) {
219 if ((int)(readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER) -
220 readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM)) >= 0 &&
221 !brcmstb_waketmr_is_pending(timer))
222 return -EINVAL;
223 timer->alarm_en = true;
224 if (timer->alarm_irq)
225 enable_irq(timer->alarm_irq);
226 } else if (!enabled && timer->alarm_en) {
227 if (timer->alarm_irq)
228 disable_irq(timer->alarm_irq);
229 timer->alarm_en = false;
230 }
231
232 return 0;
233 }
234
brcmstb_waketmr_setalarm(struct device * dev,struct rtc_wkalrm * alarm)235 static int brcmstb_waketmr_setalarm(struct device *dev,
236 struct rtc_wkalrm *alarm)
237 {
238 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
239
240 timer->rtc_alarm = rtc_tm_to_time64(&alarm->time);
241
242 brcmstb_waketmr_set_alarm(timer, timer->rtc_alarm);
243
244 return brcmstb_waketmr_alarm_enable(dev, alarm->enabled);
245 }
246
247 static const struct rtc_class_ops brcmstb_waketmr_ops = {
248 .read_time = brcmstb_waketmr_gettime,
249 .set_time = brcmstb_waketmr_settime,
250 .read_alarm = brcmstb_waketmr_getalarm,
251 .set_alarm = brcmstb_waketmr_setalarm,
252 .alarm_irq_enable = brcmstb_waketmr_alarm_enable,
253 };
254
brcmstb_waketmr_probe(struct platform_device * pdev)255 static int brcmstb_waketmr_probe(struct platform_device *pdev)
256 {
257 struct device *dev = &pdev->dev;
258 struct brcmstb_waketmr *timer;
259 int ret;
260
261 timer = devm_kzalloc(dev, sizeof(*timer), GFP_KERNEL);
262 if (!timer)
263 return -ENOMEM;
264
265 platform_set_drvdata(pdev, timer);
266 timer->dev = dev;
267
268 timer->base = devm_platform_ioremap_resource(pdev, 0);
269 if (IS_ERR(timer->base))
270 return PTR_ERR(timer->base);
271
272 timer->rtc = devm_rtc_allocate_device(dev);
273 if (IS_ERR(timer->rtc))
274 return PTR_ERR(timer->rtc);
275
276 /*
277 * Set wakeup capability before requesting wakeup interrupt, so we can
278 * process boot-time "wakeups" (e.g., from S5 soft-off)
279 */
280 device_init_wakeup(dev, true);
281
282 ret = platform_get_irq(pdev, 0);
283 if (ret < 0)
284 return -ENODEV;
285 timer->wake_irq = (unsigned int)ret;
286
287 timer->clk = devm_clk_get(dev, NULL);
288 if (!IS_ERR(timer->clk)) {
289 ret = clk_prepare_enable(timer->clk);
290 if (ret)
291 return ret;
292 timer->rate = clk_get_rate(timer->clk);
293 if (!timer->rate)
294 timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
295 } else {
296 timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
297 timer->clk = NULL;
298 }
299
300 ret = devm_request_irq(dev, timer->wake_irq, brcmstb_waketmr_irq, 0,
301 "brcmstb-waketimer", timer);
302 if (ret < 0)
303 goto err_clk;
304
305 brcmstb_waketmr_clear_alarm(timer);
306
307 /* Attempt to initialize non-wake irq */
308 ret = platform_get_irq(pdev, 1);
309 if (ret > 0) {
310 timer->alarm_irq = (unsigned int)ret;
311 ret = devm_request_irq(dev, timer->alarm_irq, brcmstb_alarm_irq,
312 IRQF_NO_AUTOEN, "brcmstb-waketimer-rtc",
313 timer);
314 if (ret < 0)
315 timer->alarm_irq = 0;
316 }
317
318 timer->reboot_notifier.notifier_call = brcmstb_waketmr_reboot;
319 register_reboot_notifier(&timer->reboot_notifier);
320
321 timer->rtc->ops = &brcmstb_waketmr_ops;
322 timer->rtc->range_max = U32_MAX;
323
324 ret = devm_rtc_register_device(timer->rtc);
325 if (ret)
326 goto err_notifier;
327
328 return 0;
329
330 err_notifier:
331 unregister_reboot_notifier(&timer->reboot_notifier);
332
333 err_clk:
334 clk_disable_unprepare(timer->clk);
335
336 return ret;
337 }
338
brcmstb_waketmr_remove(struct platform_device * pdev)339 static void brcmstb_waketmr_remove(struct platform_device *pdev)
340 {
341 struct brcmstb_waketmr *timer = dev_get_drvdata(&pdev->dev);
342
343 unregister_reboot_notifier(&timer->reboot_notifier);
344 clk_disable_unprepare(timer->clk);
345 }
346
347 #ifdef CONFIG_PM_SLEEP
brcmstb_waketmr_suspend(struct device * dev)348 static int brcmstb_waketmr_suspend(struct device *dev)
349 {
350 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
351
352 return brcmstb_waketmr_prepare_suspend(timer);
353 }
354
brcmstb_waketmr_resume(struct device * dev)355 static int brcmstb_waketmr_resume(struct device *dev)
356 {
357 struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
358 int ret;
359
360 if (!device_may_wakeup(dev))
361 return 0;
362
363 ret = disable_irq_wake(timer->wake_irq);
364 if (timer->alarm_en && timer->alarm_irq)
365 disable_irq_wake(timer->alarm_irq);
366
367 brcmstb_waketmr_clear_alarm(timer);
368
369 return ret;
370 }
371 #endif /* CONFIG_PM_SLEEP */
372
373 static SIMPLE_DEV_PM_OPS(brcmstb_waketmr_pm_ops,
374 brcmstb_waketmr_suspend, brcmstb_waketmr_resume);
375
376 static const __maybe_unused struct of_device_id brcmstb_waketmr_of_match[] = {
377 { .compatible = "brcm,brcmstb-waketimer" },
378 { /* sentinel */ },
379 };
380
381 static struct platform_driver brcmstb_waketmr_driver = {
382 .probe = brcmstb_waketmr_probe,
383 .remove_new = brcmstb_waketmr_remove,
384 .driver = {
385 .name = "brcmstb-waketimer",
386 .pm = &brcmstb_waketmr_pm_ops,
387 .of_match_table = of_match_ptr(brcmstb_waketmr_of_match),
388 }
389 };
390 module_platform_driver(brcmstb_waketmr_driver);
391
392 MODULE_LICENSE("GPL v2");
393 MODULE_AUTHOR("Brian Norris");
394 MODULE_AUTHOR("Markus Mayer");
395 MODULE_AUTHOR("Doug Berger");
396 MODULE_DESCRIPTION("Wake-up timer driver for STB chips");
397