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iio:ad_sigma_delta: Remove redundant call to iio_sw_buffer_preenable().
[linux-2.6/btrfs-unstable.git] / drivers / rtc / rtc-at91rm9200.c
blob741892632ae09ef4c561e6ee0801d6ea0cec435f
1 /*
2 * Real Time Clock interface for Linux on Atmel AT91RM9200
3 *
4 * Copyright (C) 2002 Rick Bronson
5 *
6 * Converted to RTC class model by Andrew Victor
7 *
8 * Ported to Linux 2.6 by Steven Scholz
9 * Based on s3c2410-rtc.c Simtec Electronics
10 *
11 * Based on sa1100-rtc.c by Nils Faerber
12 * Based on rtc.c by Paul Gortmaker
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
18 *
19 */
20
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/platform_device.h>
24 #include <linux/time.h>
25 #include <linux/rtc.h>
26 #include <linux/bcd.h>
27 #include <linux/interrupt.h>
28 #include <linux/spinlock.h>
29 #include <linux/ioctl.h>
30 #include <linux/completion.h>
31 #include <linux/io.h>
32 #include <linux/of.h>
33 #include <linux/of_device.h>
34 #include <linux/uaccess.h>
35
36 #include "rtc-at91rm9200.h"
37
38 #define at91_rtc_read(field) \
39 __raw_readl(at91_rtc_regs + field)
40 #define at91_rtc_write(field, val) \
41 __raw_writel((val), at91_rtc_regs + field)
42
43 #define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */
44
45 struct at91_rtc_config {
46 bool use_shadow_imr;
47 };
48
49 static const struct at91_rtc_config *at91_rtc_config;
50 static DECLARE_COMPLETION(at91_rtc_updated);
51 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
52 static void __iomem *at91_rtc_regs;
53 static int irq;
54 static DEFINE_SPINLOCK(at91_rtc_lock);
55 static u32 at91_rtc_shadow_imr;
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. When an
127 * alarm is set, at91_alarm_year will store the current year.
128 */
129 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
130 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
131
132 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
133 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
134 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
135 }
136
137 /*
138 * Read current time and date in RTC
139 */
140 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
141 {
142 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
143 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
144 tm->tm_year = tm->tm_year - 1900;
145
146 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
147 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
148 tm->tm_hour, tm->tm_min, tm->tm_sec);
149
150 return 0;
151 }
152
153 /*
154 * Set current time and date in RTC
155 */
156 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
157 {
158 unsigned long cr;
159
160 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
161 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
162 tm->tm_hour, tm->tm_min, tm->tm_sec);
163
164 /* Stop Time/Calendar from counting */
165 cr = at91_rtc_read(AT91_RTC_CR);
166 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
167
168 at91_rtc_write_ier(AT91_RTC_ACKUPD);
169 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
170 at91_rtc_write_idr(AT91_RTC_ACKUPD);
171
172 at91_rtc_write(AT91_RTC_TIMR,
173 bin2bcd(tm->tm_sec) << 0
174 | bin2bcd(tm->tm_min) << 8
175 | bin2bcd(tm->tm_hour) << 16);
176
177 at91_rtc_write(AT91_RTC_CALR,
178 bin2bcd((tm->tm_year + 1900) / 100) /* century */
179 | bin2bcd(tm->tm_year % 100) << 8 /* year */
180 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
181 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
182 | bin2bcd(tm->tm_mday) << 24);
183
184 /* Restart Time/Calendar */
185 cr = at91_rtc_read(AT91_RTC_CR);
186 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
187
188 return 0;
189 }
190
191 /*
192 * Read alarm time and date in RTC
193 */
194 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
195 {
196 struct rtc_time *tm = &alrm->time;
197
198 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
199 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
200 tm->tm_year = at91_alarm_year - 1900;
201
202 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
203 ? 1 : 0;
204
205 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
206 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
207 tm->tm_hour, tm->tm_min, tm->tm_sec);
208
209 return 0;
210 }
211
212 /*
213 * Set alarm time and date in RTC
214 */
215 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
216 {
217 struct rtc_time tm;
218
219 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
220
221 at91_alarm_year = tm.tm_year;
222
223 tm.tm_hour = alrm->time.tm_hour;
224 tm.tm_min = alrm->time.tm_min;
225 tm.tm_sec = alrm->time.tm_sec;
226
227 at91_rtc_write_idr(AT91_RTC_ALARM);
228 at91_rtc_write(AT91_RTC_TIMALR,
229 bin2bcd(tm.tm_sec) << 0
230 | bin2bcd(tm.tm_min) << 8
231 | bin2bcd(tm.tm_hour) << 16
232 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
233 at91_rtc_write(AT91_RTC_CALALR,
234 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
235 | bin2bcd(tm.tm_mday) << 24
236 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
237
238 if (alrm->enabled) {
239 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
240 at91_rtc_write_ier(AT91_RTC_ALARM);
241 }
242
243 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
244 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
245 tm.tm_min, tm.tm_sec);
246
247 return 0;
248 }
249
250 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
251 {
252 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
253
254 if (enabled) {
255 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
256 at91_rtc_write_ier(AT91_RTC_ALARM);
257 } else
258 at91_rtc_write_idr(AT91_RTC_ALARM);
259
260 return 0;
261 }
262 /*
263 * Provide additional RTC information in /proc/driver/rtc
264 */
265 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
266 {
267 unsigned long imr = at91_rtc_read_imr();
268
269 seq_printf(seq, "update_IRQ\t: %s\n",
270 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
271 seq_printf(seq, "periodic_IRQ\t: %s\n",
272 (imr & AT91_RTC_SECEV) ? "yes" : "no");
273
274 return 0;
275 }
276
277 /*
278 * IRQ handler for the RTC
279 */
280 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
281 {
282 struct platform_device *pdev = dev_id;
283 struct rtc_device *rtc = platform_get_drvdata(pdev);
284 unsigned int rtsr;
285 unsigned long events = 0;
286
287 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
288 if (rtsr) { /* this interrupt is shared! Is it ours? */
289 if (rtsr & AT91_RTC_ALARM)
290 events |= (RTC_AF | RTC_IRQF);
291 if (rtsr & AT91_RTC_SECEV)
292 events |= (RTC_UF | RTC_IRQF);
293 if (rtsr & AT91_RTC_ACKUPD)
294 complete(&at91_rtc_updated);
295
296 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
297
298 rtc_update_irq(rtc, 1, events);
299
300 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
301 events >> 8, events & 0x000000FF);
302
303 return IRQ_HANDLED;
304 }
305 return IRQ_NONE; /* not handled */
306 }
307
308 static const struct at91_rtc_config at91rm9200_config = {
309 };
310
311 static const struct at91_rtc_config at91sam9x5_config = {
312 .use_shadow_imr = true,
313 };
314
315 #ifdef CONFIG_OF
316 static const struct of_device_id at91_rtc_dt_ids[] = {
317 {
318 .compatible = "atmel,at91rm9200-rtc",
319 .data = &at91rm9200_config,
320 }, {
321 .compatible = "atmel,at91sam9x5-rtc",
322 .data = &at91sam9x5_config,
323 }, {
324 /* sentinel */
325 }
326 };
327 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
328 #endif
329
330 static const struct at91_rtc_config *
331 at91_rtc_get_config(struct platform_device *pdev)
332 {
333 const struct of_device_id *match;
334
335 if (pdev->dev.of_node) {
336 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
337 if (!match)
338 return NULL;
339 return (const struct at91_rtc_config *)match->data;
340 }
341
342 return &at91rm9200_config;
343 }
344
345 static const struct rtc_class_ops at91_rtc_ops = {
346 .read_time = at91_rtc_readtime,
347 .set_time = at91_rtc_settime,
348 .read_alarm = at91_rtc_readalarm,
349 .set_alarm = at91_rtc_setalarm,
350 .proc = at91_rtc_proc,
351 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
352 };
353
354 /*
355 * Initialize and install RTC driver
356 */
357 static int __init at91_rtc_probe(struct platform_device *pdev)
358 {
359 struct rtc_device *rtc;
360 struct resource *regs;
361 int ret = 0;
362
363 at91_rtc_config = at91_rtc_get_config(pdev);
364 if (!at91_rtc_config)
365 return -ENODEV;
366
367 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
368 if (!regs) {
369 dev_err(&pdev->dev, "no mmio resource defined\n");
370 return -ENXIO;
371 }
372
373 irq = platform_get_irq(pdev, 0);
374 if (irq < 0) {
375 dev_err(&pdev->dev, "no irq resource defined\n");
376 return -ENXIO;
377 }
378
379 at91_rtc_regs = ioremap(regs->start, resource_size(regs));
380 if (!at91_rtc_regs) {
381 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
382 return -ENOMEM;
383 }
384
385 at91_rtc_write(AT91_RTC_CR, 0);
386 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
387
388 /* Disable all interrupts */
389 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
390 AT91_RTC_SECEV | AT91_RTC_TIMEV |
391 AT91_RTC_CALEV);
392
393 ret = request_irq(irq, at91_rtc_interrupt,
394 IRQF_SHARED,
395 "at91_rtc", pdev);
396 if (ret) {
397 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
398 goto err_unmap;
399 }
400
401 /* cpu init code should really have flagged this device as
402 * being wake-capable; if it didn't, do that here.
403 */
404 if (!device_can_wakeup(&pdev->dev))
405 device_init_wakeup(&pdev->dev, 1);
406
407 rtc = rtc_device_register(pdev->name, &pdev->dev,
408 &at91_rtc_ops, THIS_MODULE);
409 if (IS_ERR(rtc)) {
410 ret = PTR_ERR(rtc);
411 goto err_free_irq;
412 }
413 platform_set_drvdata(pdev, rtc);
414
415 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
416 return 0;
417
418 err_free_irq:
419 free_irq(irq, pdev);
420 err_unmap:
421 iounmap(at91_rtc_regs);
422
423 return ret;
424 }
425
426 /*
427 * Disable and remove the RTC driver
428 */
429 static int __exit at91_rtc_remove(struct platform_device *pdev)
430 {
431 struct rtc_device *rtc = platform_get_drvdata(pdev);
432
433 /* Disable all interrupts */
434 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
435 AT91_RTC_SECEV | AT91_RTC_TIMEV |
436 AT91_RTC_CALEV);
437 free_irq(irq, pdev);
438
439 rtc_device_unregister(rtc);
440 iounmap(at91_rtc_regs);
441
442 return 0;
443 }
444
445 #ifdef CONFIG_PM_SLEEP
446
447 /* AT91RM9200 RTC Power management control */
448
449 static u32 at91_rtc_imr;
450
451 static int at91_rtc_suspend(struct device *dev)
452 {
453 /* this IRQ is shared with DBGU and other hardware which isn't
454 * necessarily doing PM like we are...
455 */
456 at91_rtc_imr = at91_rtc_read_imr()
457 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
458 if (at91_rtc_imr) {
459 if (device_may_wakeup(dev))
460 enable_irq_wake(irq);
461 else
462 at91_rtc_write_idr(at91_rtc_imr);
463 }
464 return 0;
465 }
466
467 static int at91_rtc_resume(struct device *dev)
468 {
469 if (at91_rtc_imr) {
470 if (device_may_wakeup(dev))
471 disable_irq_wake(irq);
472 else
473 at91_rtc_write_ier(at91_rtc_imr);
474 }
475 return 0;
476 }
477 #endif
478
479 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
480
481 static struct platform_driver at91_rtc_driver = {
482 .remove = __exit_p(at91_rtc_remove),
483 .driver = {
484 .name = "at91_rtc",
485 .owner = THIS_MODULE,
486 .pm = &at91_rtc_pm_ops,
487 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
488 },
489 };
490
491 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
492
493 MODULE_AUTHOR("Rick Bronson");
494 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
495 MODULE_LICENSE("GPL");
496 MODULE_ALIAS("platform:at91_rtc");
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