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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / rtc / rtc-at91rm9200.c
blob3b833e02a6575fd4bcaf6ec16b0433a0e9f2b552
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Real Time Clock interface for Linux on Atmel AT91RM9200
4 *
5 * Copyright (C) 2002 Rick Bronson
6 *
7 * Converted to RTC class model by Andrew Victor
8 *
9 * Ported to Linux 2.6 by Steven Scholz
10 * Based on s3c2410-rtc.c Simtec Electronics
11 *
12 * Based on sa1100-rtc.c by Nils Faerber
13 * Based on rtc.c by Paul Gortmaker
14 */
15
16 #include <linux/bcd.h>
17 #include <linux/clk.h>
18 #include <linux/completion.h>
19 #include <linux/interrupt.h>
20 #include <linux/ioctl.h>
21 #include <linux/io.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/of_device.h>
25 #include <linux/of.h>
26 #include <linux/platform_device.h>
27 #include <linux/rtc.h>
28 #include <linux/spinlock.h>
29 #include <linux/suspend.h>
30 #include <linux/time.h>
31 #include <linux/uaccess.h>
32
33 #include "rtc-at91rm9200.h"
34
35 #define at91_rtc_read(field) \
36 readl_relaxed(at91_rtc_regs + field)
37 #define at91_rtc_write(field, val) \
38 writel_relaxed((val), at91_rtc_regs + field)
39
40 struct at91_rtc_config {
41 bool use_shadow_imr;
42 };
43
44 static const struct at91_rtc_config *at91_rtc_config;
45 static DECLARE_COMPLETION(at91_rtc_updated);
46 static DECLARE_COMPLETION(at91_rtc_upd_rdy);
47 static void __iomem *at91_rtc_regs;
48 static int irq;
49 static DEFINE_SPINLOCK(at91_rtc_lock);
50 static u32 at91_rtc_shadow_imr;
51 static bool suspended;
52 static DEFINE_SPINLOCK(suspended_lock);
53 static unsigned long cached_events;
54 static u32 at91_rtc_imr;
55 static struct clk *sclk;
56
57 static void at91_rtc_write_ier(u32 mask)
58 {
59 unsigned long flags;
60
61 spin_lock_irqsave(&at91_rtc_lock, flags);
62 at91_rtc_shadow_imr |= mask;
63 at91_rtc_write(AT91_RTC_IER, mask);
64 spin_unlock_irqrestore(&at91_rtc_lock, flags);
65 }
66
67 static void at91_rtc_write_idr(u32 mask)
68 {
69 unsigned long flags;
70
71 spin_lock_irqsave(&at91_rtc_lock, flags);
72 at91_rtc_write(AT91_RTC_IDR, mask);
73 /*
74 * Register read back (of any RTC-register) needed to make sure
75 * IDR-register write has reached the peripheral before updating
76 * shadow mask.
77 *
78 * Note that there is still a possibility that the mask is updated
79 * before interrupts have actually been disabled in hardware. The only
80 * way to be certain would be to poll the IMR-register, which is is
81 * the very register we are trying to emulate. The register read back
82 * is a reasonable heuristic.
83 */
84 at91_rtc_read(AT91_RTC_SR);
85 at91_rtc_shadow_imr &= ~mask;
86 spin_unlock_irqrestore(&at91_rtc_lock, flags);
87 }
88
89 static u32 at91_rtc_read_imr(void)
90 {
91 unsigned long flags;
92 u32 mask;
93
94 if (at91_rtc_config->use_shadow_imr) {
95 spin_lock_irqsave(&at91_rtc_lock, flags);
96 mask = at91_rtc_shadow_imr;
97 spin_unlock_irqrestore(&at91_rtc_lock, flags);
98 } else {
99 mask = at91_rtc_read(AT91_RTC_IMR);
100 }
101
102 return mask;
103 }
104
105 /*
106 * Decode time/date into rtc_time structure
107 */
108 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
109 struct rtc_time *tm)
110 {
111 unsigned int time, date;
112
113 /* must read twice in case it changes */
114 do {
115 time = at91_rtc_read(timereg);
116 date = at91_rtc_read(calreg);
117 } while ((time != at91_rtc_read(timereg)) ||
118 (date != at91_rtc_read(calreg)));
119
120 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0);
121 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8);
122 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
123
124 /*
125 * The Calendar Alarm register does not have a field for
126 * the year - so these will return an invalid value.
127 */
128 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
129 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
130
131 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
132 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
133 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
134 }
135
136 /*
137 * Read current time and date in RTC
138 */
139 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
140 {
141 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
142 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
143 tm->tm_year = tm->tm_year - 1900;
144
145 dev_dbg(dev, "%s(): %ptR\n", __func__, tm);
146
147 return 0;
148 }
149
150 /*
151 * Set current time and date in RTC
152 */
153 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
154 {
155 unsigned long cr;
156
157 dev_dbg(dev, "%s(): %ptR\n", __func__, tm);
158
159 wait_for_completion(&at91_rtc_upd_rdy);
160
161 /* Stop Time/Calendar from counting */
162 cr = at91_rtc_read(AT91_RTC_CR);
163 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
164
165 at91_rtc_write_ier(AT91_RTC_ACKUPD);
166 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
167 at91_rtc_write_idr(AT91_RTC_ACKUPD);
168
169 at91_rtc_write(AT91_RTC_TIMR,
170 bin2bcd(tm->tm_sec) << 0
171 | bin2bcd(tm->tm_min) << 8
172 | bin2bcd(tm->tm_hour) << 16);
173
174 at91_rtc_write(AT91_RTC_CALR,
175 bin2bcd((tm->tm_year + 1900) / 100) /* century */
176 | bin2bcd(tm->tm_year % 100) << 8 /* year */
177 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
178 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
179 | bin2bcd(tm->tm_mday) << 24);
180
181 /* Restart Time/Calendar */
182 cr = at91_rtc_read(AT91_RTC_CR);
183 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
184 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
185 at91_rtc_write_ier(AT91_RTC_SECEV);
186
187 return 0;
188 }
189
190 /*
191 * Read alarm time and date in RTC
192 */
193 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
194 {
195 struct rtc_time *tm = &alrm->time;
196
197 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
198 tm->tm_year = -1;
199
200 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
201 ? 1 : 0;
202
203 dev_dbg(dev, "%s(): %ptR %sabled\n", __func__, tm,
204 alrm->enabled ? "en" : "dis");
205
206 return 0;
207 }
208
209 /*
210 * Set alarm time and date in RTC
211 */
212 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
213 {
214 struct rtc_time tm;
215
216 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
217
218 tm.tm_mon = alrm->time.tm_mon;
219 tm.tm_mday = alrm->time.tm_mday;
220 tm.tm_hour = alrm->time.tm_hour;
221 tm.tm_min = alrm->time.tm_min;
222 tm.tm_sec = alrm->time.tm_sec;
223
224 at91_rtc_write_idr(AT91_RTC_ALARM);
225 at91_rtc_write(AT91_RTC_TIMALR,
226 bin2bcd(tm.tm_sec) << 0
227 | bin2bcd(tm.tm_min) << 8
228 | bin2bcd(tm.tm_hour) << 16
229 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
230 at91_rtc_write(AT91_RTC_CALALR,
231 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
232 | bin2bcd(tm.tm_mday) << 24
233 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
234
235 if (alrm->enabled) {
236 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
237 at91_rtc_write_ier(AT91_RTC_ALARM);
238 }
239
240 dev_dbg(dev, "%s(): %ptR\n", __func__, &tm);
241
242 return 0;
243 }
244
245 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
246 {
247 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
248
249 if (enabled) {
250 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
251 at91_rtc_write_ier(AT91_RTC_ALARM);
252 } else
253 at91_rtc_write_idr(AT91_RTC_ALARM);
254
255 return 0;
256 }
257 /*
258 * Provide additional RTC information in /proc/driver/rtc
259 */
260 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
261 {
262 unsigned long imr = at91_rtc_read_imr();
263
264 seq_printf(seq, "update_IRQ\t: %s\n",
265 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
266 seq_printf(seq, "periodic_IRQ\t: %s\n",
267 (imr & AT91_RTC_SECEV) ? "yes" : "no");
268
269 return 0;
270 }
271
272 /*
273 * IRQ handler for the RTC
274 */
275 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
276 {
277 struct platform_device *pdev = dev_id;
278 struct rtc_device *rtc = platform_get_drvdata(pdev);
279 unsigned int rtsr;
280 unsigned long events = 0;
281 int ret = IRQ_NONE;
282
283 spin_lock(&suspended_lock);
284 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
285 if (rtsr) { /* this interrupt is shared! Is it ours? */
286 if (rtsr & AT91_RTC_ALARM)
287 events |= (RTC_AF | RTC_IRQF);
288 if (rtsr & AT91_RTC_SECEV) {
289 complete(&at91_rtc_upd_rdy);
290 at91_rtc_write_idr(AT91_RTC_SECEV);
291 }
292 if (rtsr & AT91_RTC_ACKUPD)
293 complete(&at91_rtc_updated);
294
295 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
296
297 if (!suspended) {
298 rtc_update_irq(rtc, 1, events);
299
300 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
301 __func__, events >> 8, events & 0x000000FF);
302 } else {
303 cached_events |= events;
304 at91_rtc_write_idr(at91_rtc_imr);
305 pm_system_wakeup();
306 }
307
308 ret = IRQ_HANDLED;
309 }
310 spin_unlock(&suspended_lock);
311
312 return ret;
313 }
314
315 static const struct at91_rtc_config at91rm9200_config = {
316 };
317
318 static const struct at91_rtc_config at91sam9x5_config = {
319 .use_shadow_imr = true,
320 };
321
322 static const struct of_device_id at91_rtc_dt_ids[] = {
323 {
324 .compatible = "atmel,at91rm9200-rtc",
325 .data = &at91rm9200_config,
326 }, {
327 .compatible = "atmel,at91sam9x5-rtc",
328 .data = &at91sam9x5_config,
329 }, {
330 /* sentinel */
331 }
332 };
333 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
334
335 static const struct rtc_class_ops at91_rtc_ops = {
336 .read_time = at91_rtc_readtime,
337 .set_time = at91_rtc_settime,
338 .read_alarm = at91_rtc_readalarm,
339 .set_alarm = at91_rtc_setalarm,
340 .proc = at91_rtc_proc,
341 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
342 };
343
344 /*
345 * Initialize and install RTC driver
346 */
347 static int __init at91_rtc_probe(struct platform_device *pdev)
348 {
349 struct rtc_device *rtc;
350 struct resource *regs;
351 int ret = 0;
352
353 at91_rtc_config = of_device_get_match_data(&pdev->dev);
354 if (!at91_rtc_config)
355 return -ENODEV;
356
357 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
358 if (!regs) {
359 dev_err(&pdev->dev, "no mmio resource defined\n");
360 return -ENXIO;
361 }
362
363 irq = platform_get_irq(pdev, 0);
364 if (irq < 0)
365 return -ENXIO;
366
367 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
368 resource_size(regs));
369 if (!at91_rtc_regs) {
370 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
371 return -ENOMEM;
372 }
373
374 rtc = devm_rtc_allocate_device(&pdev->dev);
375 if (IS_ERR(rtc))
376 return PTR_ERR(rtc);
377 platform_set_drvdata(pdev, rtc);
378
379 sclk = devm_clk_get(&pdev->dev, NULL);
380 if (IS_ERR(sclk))
381 return PTR_ERR(sclk);
382
383 ret = clk_prepare_enable(sclk);
384 if (ret) {
385 dev_err(&pdev->dev, "Could not enable slow clock\n");
386 return ret;
387 }
388
389 at91_rtc_write(AT91_RTC_CR, 0);
390 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
391
392 /* Disable all interrupts */
393 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
394 AT91_RTC_SECEV | AT91_RTC_TIMEV |
395 AT91_RTC_CALEV);
396
397 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
398 IRQF_SHARED | IRQF_COND_SUSPEND,
399 "at91_rtc", pdev);
400 if (ret) {
401 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
402 goto err_clk;
403 }
404
405 /* cpu init code should really have flagged this device as
406 * being wake-capable; if it didn't, do that here.
407 */
408 if (!device_can_wakeup(&pdev->dev))
409 device_init_wakeup(&pdev->dev, 1);
410
411 rtc->ops = &at91_rtc_ops;
412 rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
413 rtc->range_max = RTC_TIMESTAMP_END_2099;
414 ret = rtc_register_device(rtc);
415 if (ret)
416 goto err_clk;
417
418 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
419 * completion.
420 */
421 at91_rtc_write_ier(AT91_RTC_SECEV);
422
423 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
424 return 0;
425
426 err_clk:
427 clk_disable_unprepare(sclk);
428
429 return ret;
430 }
431
432 /*
433 * Disable and remove the RTC driver
434 */
435 static int __exit at91_rtc_remove(struct platform_device *pdev)
436 {
437 /* Disable all interrupts */
438 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
439 AT91_RTC_SECEV | AT91_RTC_TIMEV |
440 AT91_RTC_CALEV);
441
442 clk_disable_unprepare(sclk);
443
444 return 0;
445 }
446
447 static void at91_rtc_shutdown(struct platform_device *pdev)
448 {
449 /* Disable all interrupts */
450 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
451 AT91_RTC_SECEV | AT91_RTC_TIMEV |
452 AT91_RTC_CALEV);
453 }
454
455 #ifdef CONFIG_PM_SLEEP
456
457 /* AT91RM9200 RTC Power management control */
458
459 static int at91_rtc_suspend(struct device *dev)
460 {
461 /* this IRQ is shared with DBGU and other hardware which isn't
462 * necessarily doing PM like we are...
463 */
464 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
465
466 at91_rtc_imr = at91_rtc_read_imr()
467 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
468 if (at91_rtc_imr) {
469 if (device_may_wakeup(dev)) {
470 unsigned long flags;
471
472 enable_irq_wake(irq);
473
474 spin_lock_irqsave(&suspended_lock, flags);
475 suspended = true;
476 spin_unlock_irqrestore(&suspended_lock, flags);
477 } else {
478 at91_rtc_write_idr(at91_rtc_imr);
479 }
480 }
481 return 0;
482 }
483
484 static int at91_rtc_resume(struct device *dev)
485 {
486 struct rtc_device *rtc = dev_get_drvdata(dev);
487
488 if (at91_rtc_imr) {
489 if (device_may_wakeup(dev)) {
490 unsigned long flags;
491
492 spin_lock_irqsave(&suspended_lock, flags);
493
494 if (cached_events) {
495 rtc_update_irq(rtc, 1, cached_events);
496 cached_events = 0;
497 }
498
499 suspended = false;
500 spin_unlock_irqrestore(&suspended_lock, flags);
501
502 disable_irq_wake(irq);
503 }
504 at91_rtc_write_ier(at91_rtc_imr);
505 }
506 return 0;
507 }
508 #endif
509
510 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
511
512 static struct platform_driver at91_rtc_driver = {
513 .remove = __exit_p(at91_rtc_remove),
514 .shutdown = at91_rtc_shutdown,
515 .driver = {
516 .name = "at91_rtc",
517 .pm = &at91_rtc_pm_ops,
518 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
519 },
520 };
521
522 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
523
524 MODULE_AUTHOR("Rick Bronson");
525 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
526 MODULE_LICENSE("GPL");
527 MODULE_ALIAS("platform:at91_rtc");
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