rtc: rtc-omap footprint shrinkage
[linux-2.6.git] / drivers / rtc / rtc-omap.c
1 /*
2  * TI OMAP1 Real Time Clock interface for Linux
3  *
4  * Copyright (C) 2003 MontaVista Software, Inc.
5  * Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com>
6  *
7  * Copyright (C) 2006 David Brownell (new RTC framework)
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version
12  * 2 of the License, or (at your option) any later version.
13  */
14
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/ioport.h>
19 #include <linux/delay.h>
20 #include <linux/rtc.h>
21 #include <linux/bcd.h>
22 #include <linux/platform_device.h>
23
24 #include <asm/io.h>
25
26
27 /* The OMAP1 RTC is a year/month/day/hours/minutes/seconds BCD clock
28  * with century-range alarm matching, driven by the 32kHz clock.
29  *
30  * The main user-visible ways it differs from PC RTCs are by omitting
31  * "don't care" alarm fields and sub-second periodic IRQs, and having
32  * an autoadjust mechanism to calibrate to the true oscillator rate.
33  *
34  * Board-specific wiring options include using split power mode with
35  * RTC_OFF_NOFF used as the reset signal (so the RTC won't be reset),
36  * and wiring RTC_WAKE_INT (so the RTC alarm can wake the system from
37  * low power modes).  See the BOARD-SPECIFIC CUSTOMIZATION comment.
38  */
39
40 #define OMAP_RTC_BASE                   0xfffb4800
41
42 /* RTC registers */
43 #define OMAP_RTC_SECONDS_REG            0x00
44 #define OMAP_RTC_MINUTES_REG            0x04
45 #define OMAP_RTC_HOURS_REG              0x08
46 #define OMAP_RTC_DAYS_REG               0x0C
47 #define OMAP_RTC_MONTHS_REG             0x10
48 #define OMAP_RTC_YEARS_REG              0x14
49 #define OMAP_RTC_WEEKS_REG              0x18
50
51 #define OMAP_RTC_ALARM_SECONDS_REG      0x20
52 #define OMAP_RTC_ALARM_MINUTES_REG      0x24
53 #define OMAP_RTC_ALARM_HOURS_REG        0x28
54 #define OMAP_RTC_ALARM_DAYS_REG         0x2c
55 #define OMAP_RTC_ALARM_MONTHS_REG       0x30
56 #define OMAP_RTC_ALARM_YEARS_REG        0x34
57
58 #define OMAP_RTC_CTRL_REG               0x40
59 #define OMAP_RTC_STATUS_REG             0x44
60 #define OMAP_RTC_INTERRUPTS_REG         0x48
61
62 #define OMAP_RTC_COMP_LSB_REG           0x4c
63 #define OMAP_RTC_COMP_MSB_REG           0x50
64 #define OMAP_RTC_OSC_REG                0x54
65
66 /* OMAP_RTC_CTRL_REG bit fields: */
67 #define OMAP_RTC_CTRL_SPLIT             (1<<7)
68 #define OMAP_RTC_CTRL_DISABLE           (1<<6)
69 #define OMAP_RTC_CTRL_SET_32_COUNTER    (1<<5)
70 #define OMAP_RTC_CTRL_TEST              (1<<4)
71 #define OMAP_RTC_CTRL_MODE_12_24        (1<<3)
72 #define OMAP_RTC_CTRL_AUTO_COMP         (1<<2)
73 #define OMAP_RTC_CTRL_ROUND_30S         (1<<1)
74 #define OMAP_RTC_CTRL_STOP              (1<<0)
75
76 /* OMAP_RTC_STATUS_REG bit fields: */
77 #define OMAP_RTC_STATUS_POWER_UP        (1<<7)
78 #define OMAP_RTC_STATUS_ALARM           (1<<6)
79 #define OMAP_RTC_STATUS_1D_EVENT        (1<<5)
80 #define OMAP_RTC_STATUS_1H_EVENT        (1<<4)
81 #define OMAP_RTC_STATUS_1M_EVENT        (1<<3)
82 #define OMAP_RTC_STATUS_1S_EVENT        (1<<2)
83 #define OMAP_RTC_STATUS_RUN             (1<<1)
84 #define OMAP_RTC_STATUS_BUSY            (1<<0)
85
86 /* OMAP_RTC_INTERRUPTS_REG bit fields: */
87 #define OMAP_RTC_INTERRUPTS_IT_ALARM    (1<<3)
88 #define OMAP_RTC_INTERRUPTS_IT_TIMER    (1<<2)
89
90
91 #define rtc_read(addr)          omap_readb(OMAP_RTC_BASE + (addr))
92 #define rtc_write(val, addr)    omap_writeb(val, OMAP_RTC_BASE + (addr))
93
94
95 /* we rely on the rtc framework to handle locking (rtc->ops_lock),
96  * so the only other requirement is that register accesses which
97  * require BUSY to be clear are made with IRQs locally disabled
98  */
99 static void rtc_wait_not_busy(void)
100 {
101         int     count = 0;
102         u8      status;
103
104         /* BUSY may stay active for 1/32768 second (~30 usec) */
105         for (count = 0; count < 50; count++) {
106                 status = rtc_read(OMAP_RTC_STATUS_REG);
107                 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
108                         break;
109                 udelay(1);
110         }
111         /* now we have ~15 usec to read/write various registers */
112 }
113
114 static irqreturn_t rtc_irq(int irq, void *rtc)
115 {
116         unsigned long           events = 0;
117         u8                      irq_data;
118
119         irq_data = rtc_read(OMAP_RTC_STATUS_REG);
120
121         /* alarm irq? */
122         if (irq_data & OMAP_RTC_STATUS_ALARM) {
123                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
124                 events |= RTC_IRQF | RTC_AF;
125         }
126
127         /* 1/sec periodic/update irq? */
128         if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
129                 events |= RTC_IRQF | RTC_UF;
130
131         rtc_update_irq(rtc, 1, events);
132
133         return IRQ_HANDLED;
134 }
135
136 #ifdef  CONFIG_RTC_INTF_DEV
137
138 static int
139 omap_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
140 {
141         u8 reg;
142
143         switch (cmd) {
144         case RTC_AIE_OFF:
145         case RTC_AIE_ON:
146         case RTC_UIE_OFF:
147         case RTC_UIE_ON:
148                 break;
149         default:
150                 return -ENOIOCTLCMD;
151         }
152
153         local_irq_disable();
154         rtc_wait_not_busy();
155         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
156         switch (cmd) {
157         /* AIE = Alarm Interrupt Enable */
158         case RTC_AIE_OFF:
159                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
160                 break;
161         case RTC_AIE_ON:
162                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
163                 break;
164         /* UIE = Update Interrupt Enable (1/second) */
165         case RTC_UIE_OFF:
166                 reg &= ~OMAP_RTC_INTERRUPTS_IT_TIMER;
167                 break;
168         case RTC_UIE_ON:
169                 reg |= OMAP_RTC_INTERRUPTS_IT_TIMER;
170                 break;
171         }
172         rtc_wait_not_busy();
173         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
174         local_irq_enable();
175
176         return 0;
177 }
178
179 #else
180 #define omap_rtc_ioctl  NULL
181 #endif
182
183 /* this hardware doesn't support "don't care" alarm fields */
184 static int tm2bcd(struct rtc_time *tm)
185 {
186         if (rtc_valid_tm(tm) != 0)
187                 return -EINVAL;
188
189         tm->tm_sec = BIN2BCD(tm->tm_sec);
190         tm->tm_min = BIN2BCD(tm->tm_min);
191         tm->tm_hour = BIN2BCD(tm->tm_hour);
192         tm->tm_mday = BIN2BCD(tm->tm_mday);
193
194         tm->tm_mon = BIN2BCD(tm->tm_mon + 1);
195
196         /* epoch == 1900 */
197         if (tm->tm_year < 100 || tm->tm_year > 199)
198                 return -EINVAL;
199         tm->tm_year = BIN2BCD(tm->tm_year - 100);
200
201         return 0;
202 }
203
204 static void bcd2tm(struct rtc_time *tm)
205 {
206         tm->tm_sec = BCD2BIN(tm->tm_sec);
207         tm->tm_min = BCD2BIN(tm->tm_min);
208         tm->tm_hour = BCD2BIN(tm->tm_hour);
209         tm->tm_mday = BCD2BIN(tm->tm_mday);
210         tm->tm_mon = BCD2BIN(tm->tm_mon) - 1;
211         /* epoch == 1900 */
212         tm->tm_year = BCD2BIN(tm->tm_year) + 100;
213 }
214
215
216 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
217 {
218         /* we don't report wday/yday/isdst ... */
219         local_irq_disable();
220         rtc_wait_not_busy();
221
222         tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
223         tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
224         tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
225         tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
226         tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
227         tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
228
229         local_irq_enable();
230
231         bcd2tm(tm);
232         return 0;
233 }
234
235 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
236 {
237         if (tm2bcd(tm) < 0)
238                 return -EINVAL;
239         local_irq_disable();
240         rtc_wait_not_busy();
241
242         rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
243         rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
244         rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
245         rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
246         rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
247         rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
248
249         local_irq_enable();
250
251         return 0;
252 }
253
254 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
255 {
256         local_irq_disable();
257         rtc_wait_not_busy();
258
259         alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
260         alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
261         alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
262         alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
263         alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
264         alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
265
266         local_irq_enable();
267
268         bcd2tm(&alm->time);
269         alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
270                         & OMAP_RTC_INTERRUPTS_IT_ALARM);
271
272         return 0;
273 }
274
275 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
276 {
277         u8 reg;
278
279         if (tm2bcd(&alm->time) < 0)
280                 return -EINVAL;
281
282         local_irq_disable();
283         rtc_wait_not_busy();
284
285         rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
286         rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
287         rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
288         rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
289         rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
290         rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
291
292         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
293         if (alm->enabled)
294                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
295         else
296                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
297         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
298
299         local_irq_enable();
300
301         return 0;
302 }
303
304 static struct rtc_class_ops omap_rtc_ops = {
305         .ioctl          = omap_rtc_ioctl,
306         .read_time      = omap_rtc_read_time,
307         .set_time       = omap_rtc_set_time,
308         .read_alarm     = omap_rtc_read_alarm,
309         .set_alarm      = omap_rtc_set_alarm,
310 };
311
312 static int omap_rtc_alarm;
313 static int omap_rtc_timer;
314
315 static int __init omap_rtc_probe(struct platform_device *pdev)
316 {
317         struct resource         *res, *mem;
318         struct rtc_device       *rtc;
319         u8                      reg, new_ctrl;
320
321         omap_rtc_timer = platform_get_irq(pdev, 0);
322         if (omap_rtc_timer <= 0) {
323                 pr_debug("%s: no update irq?\n", pdev->name);
324                 return -ENOENT;
325         }
326
327         omap_rtc_alarm = platform_get_irq(pdev, 1);
328         if (omap_rtc_alarm <= 0) {
329                 pr_debug("%s: no alarm irq?\n", pdev->name);
330                 return -ENOENT;
331         }
332
333         /* NOTE:  using static mapping for RTC registers */
334         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
335         if (res && res->start != OMAP_RTC_BASE) {
336                 pr_debug("%s: RTC registers at %08x, expected %08x\n",
337                         pdev->name, (unsigned) res->start, OMAP_RTC_BASE);
338                 return -ENOENT;
339         }
340
341         if (res)
342                 mem = request_mem_region(res->start,
343                                 res->end - res->start + 1,
344                                 pdev->name);
345         else
346                 mem = NULL;
347         if (!mem) {
348                 pr_debug("%s: RTC registers at %08x are not free\n",
349                         pdev->name, OMAP_RTC_BASE);
350                 return -EBUSY;
351         }
352
353         rtc = rtc_device_register(pdev->name, &pdev->dev,
354                         &omap_rtc_ops, THIS_MODULE);
355         if (IS_ERR(rtc)) {
356                 pr_debug("%s: can't register RTC device, err %ld\n",
357                         pdev->name, PTR_ERR(rtc));
358                 goto fail;
359         }
360         platform_set_drvdata(pdev, rtc);
361         dev_set_drvdata(&rtc->dev, mem);
362
363         /* clear pending irqs, and set 1/second periodic,
364          * which we'll use instead of update irqs
365          */
366         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
367
368         /* clear old status */
369         reg = rtc_read(OMAP_RTC_STATUS_REG);
370         if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
371                 pr_info("%s: RTC power up reset detected\n",
372                         pdev->name);
373                 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
374         }
375         if (reg & (u8) OMAP_RTC_STATUS_ALARM)
376                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
377
378         /* handle periodic and alarm irqs */
379         if (request_irq(omap_rtc_timer, rtc_irq, IRQF_DISABLED,
380                         rtc->dev.bus_id, rtc)) {
381                 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
382                         pdev->name, omap_rtc_timer);
383                 goto fail0;
384         }
385         if (request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED,
386                         rtc->dev.bus_id, rtc)) {
387                 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
388                         pdev->name, omap_rtc_alarm);
389                 goto fail1;
390         }
391
392         /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
393         reg = rtc_read(OMAP_RTC_CTRL_REG);
394         if (reg & (u8) OMAP_RTC_CTRL_STOP)
395                 pr_info("%s: already running\n", pdev->name);
396
397         /* force to 24 hour mode */
398         new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
399         new_ctrl |= OMAP_RTC_CTRL_STOP;
400
401         /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
402          *
403          *  - Boards wired so that RTC_WAKE_INT does something, and muxed
404          *    right (W13_1610_RTC_WAKE_INT is the default after chip reset),
405          *    should initialize the device wakeup flag appropriately.
406          *
407          *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
408          *    rather than nPWRON_RESET, should forcibly enable split
409          *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
410          *    is write-only, and always reads as zero...)
411          */
412         device_init_wakeup(&pdev->dev, 0);
413
414         if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT)
415                 pr_info("%s: split power mode\n", pdev->name);
416
417         if (reg != new_ctrl)
418                 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG);
419
420         return 0;
421
422 fail1:
423         free_irq(omap_rtc_timer, NULL);
424 fail0:
425         rtc_device_unregister(rtc);
426 fail:
427         release_resource(mem);
428         return -EIO;
429 }
430
431 static int __exit omap_rtc_remove(struct platform_device *pdev)
432 {
433         struct rtc_device       *rtc = platform_get_drvdata(pdev);;
434
435         device_init_wakeup(&pdev->dev, 0);
436
437         /* leave rtc running, but disable irqs */
438         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
439
440         free_irq(omap_rtc_timer, rtc);
441         free_irq(omap_rtc_alarm, rtc);
442
443         release_resource(dev_get_drvdata(&rtc->dev));
444         rtc_device_unregister(rtc);
445         return 0;
446 }
447
448 #ifdef CONFIG_PM
449
450 static u8 irqstat;
451
452 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state)
453 {
454         irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
455
456         /* FIXME the RTC alarm is not currently acting as a wakeup event
457          * source, and in fact this enable() call is just saving a flag
458          * that's never used...
459          */
460         if (device_may_wakeup(&pdev->dev))
461                 enable_irq_wake(omap_rtc_alarm);
462         else
463                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
464
465         return 0;
466 }
467
468 static int omap_rtc_resume(struct platform_device *pdev)
469 {
470         if (device_may_wakeup(&pdev->dev))
471                 disable_irq_wake(omap_rtc_alarm);
472         else
473                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
474         return 0;
475 }
476
477 #else
478 #define omap_rtc_suspend NULL
479 #define omap_rtc_resume  NULL
480 #endif
481
482 static void omap_rtc_shutdown(struct platform_device *pdev)
483 {
484         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
485 }
486
487 MODULE_ALIAS("platform:omap_rtc");
488 static struct platform_driver omap_rtc_driver = {
489         .remove         = __exit_p(omap_rtc_remove),
490         .suspend        = omap_rtc_suspend,
491         .resume         = omap_rtc_resume,
492         .shutdown       = omap_rtc_shutdown,
493         .driver         = {
494                 .name   = "omap_rtc",
495                 .owner  = THIS_MODULE,
496         },
497 };
498
499 static int __init rtc_init(void)
500 {
501         return platform_driver_probe(&omap_rtc_driver, omap_rtc_probe);
502 }
503 module_init(rtc_init);
504
505 static void __exit rtc_exit(void)
506 {
507         platform_driver_unregister(&omap_rtc_driver);
508 }
509 module_exit(rtc_exit);
510
511 MODULE_AUTHOR("George G. Davis (and others)");
512 MODULE_LICENSE("GPL");