1/*
2 * rtc-twl.c -- TWL Real Time Clock interface
3 *
4 * Copyright (C) 2007 MontaVista Software, Inc
5 * Author: Alexandre Rusev <source@mvista.com>
6 *
7 * Based on original TI driver twl4030-rtc.c
8 *   Copyright (C) 2006 Texas Instruments, Inc.
9 *
10 * Based on rtc-omap.c
11 *   Copyright (C) 2003 MontaVista Software, Inc.
12 *   Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com>
13 *   Copyright (C) 2006 David Brownell
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
19 */
20
21#include <linux/kernel.h>
22#include <linux/errno.h>
23#include <linux/init.h>
24#include <linux/module.h>
25#include <linux/types.h>
26#include <linux/rtc.h>
27#include <linux/bcd.h>
28#include <linux/platform_device.h>
29#include <linux/interrupt.h>
30#include <linux/of.h>
31
32#include <linux/i2c/twl.h>
33
34
35/*
36 * RTC block register offsets (use TWL_MODULE_RTC)
37 */
38enum {
39	REG_SECONDS_REG = 0,
40	REG_MINUTES_REG,
41	REG_HOURS_REG,
42	REG_DAYS_REG,
43	REG_MONTHS_REG,
44	REG_YEARS_REG,
45	REG_WEEKS_REG,
46
47	REG_ALARM_SECONDS_REG,
48	REG_ALARM_MINUTES_REG,
49	REG_ALARM_HOURS_REG,
50	REG_ALARM_DAYS_REG,
51	REG_ALARM_MONTHS_REG,
52	REG_ALARM_YEARS_REG,
53
54	REG_RTC_CTRL_REG,
55	REG_RTC_STATUS_REG,
56	REG_RTC_INTERRUPTS_REG,
57
58	REG_RTC_COMP_LSB_REG,
59	REG_RTC_COMP_MSB_REG,
60};
61static const u8 twl4030_rtc_reg_map[] = {
62	[REG_SECONDS_REG] = 0x00,
63	[REG_MINUTES_REG] = 0x01,
64	[REG_HOURS_REG] = 0x02,
65	[REG_DAYS_REG] = 0x03,
66	[REG_MONTHS_REG] = 0x04,
67	[REG_YEARS_REG] = 0x05,
68	[REG_WEEKS_REG] = 0x06,
69
70	[REG_ALARM_SECONDS_REG] = 0x07,
71	[REG_ALARM_MINUTES_REG] = 0x08,
72	[REG_ALARM_HOURS_REG] = 0x09,
73	[REG_ALARM_DAYS_REG] = 0x0A,
74	[REG_ALARM_MONTHS_REG] = 0x0B,
75	[REG_ALARM_YEARS_REG] = 0x0C,
76
77	[REG_RTC_CTRL_REG] = 0x0D,
78	[REG_RTC_STATUS_REG] = 0x0E,
79	[REG_RTC_INTERRUPTS_REG] = 0x0F,
80
81	[REG_RTC_COMP_LSB_REG] = 0x10,
82	[REG_RTC_COMP_MSB_REG] = 0x11,
83};
84static const u8 twl6030_rtc_reg_map[] = {
85	[REG_SECONDS_REG] = 0x00,
86	[REG_MINUTES_REG] = 0x01,
87	[REG_HOURS_REG] = 0x02,
88	[REG_DAYS_REG] = 0x03,
89	[REG_MONTHS_REG] = 0x04,
90	[REG_YEARS_REG] = 0x05,
91	[REG_WEEKS_REG] = 0x06,
92
93	[REG_ALARM_SECONDS_REG] = 0x08,
94	[REG_ALARM_MINUTES_REG] = 0x09,
95	[REG_ALARM_HOURS_REG] = 0x0A,
96	[REG_ALARM_DAYS_REG] = 0x0B,
97	[REG_ALARM_MONTHS_REG] = 0x0C,
98	[REG_ALARM_YEARS_REG] = 0x0D,
99
100	[REG_RTC_CTRL_REG] = 0x10,
101	[REG_RTC_STATUS_REG] = 0x11,
102	[REG_RTC_INTERRUPTS_REG] = 0x12,
103
104	[REG_RTC_COMP_LSB_REG] = 0x13,
105	[REG_RTC_COMP_MSB_REG] = 0x14,
106};
107
108/* RTC_CTRL_REG bitfields */
109#define BIT_RTC_CTRL_REG_STOP_RTC_M              0x01
110#define BIT_RTC_CTRL_REG_ROUND_30S_M             0x02
111#define BIT_RTC_CTRL_REG_AUTO_COMP_M             0x04
112#define BIT_RTC_CTRL_REG_MODE_12_24_M            0x08
113#define BIT_RTC_CTRL_REG_TEST_MODE_M             0x10
114#define BIT_RTC_CTRL_REG_SET_32_COUNTER_M        0x20
115#define BIT_RTC_CTRL_REG_GET_TIME_M              0x40
116#define BIT_RTC_CTRL_REG_RTC_V_OPT               0x80
117
118/* RTC_STATUS_REG bitfields */
119#define BIT_RTC_STATUS_REG_RUN_M                 0x02
120#define BIT_RTC_STATUS_REG_1S_EVENT_M            0x04
121#define BIT_RTC_STATUS_REG_1M_EVENT_M            0x08
122#define BIT_RTC_STATUS_REG_1H_EVENT_M            0x10
123#define BIT_RTC_STATUS_REG_1D_EVENT_M            0x20
124#define BIT_RTC_STATUS_REG_ALARM_M               0x40
125#define BIT_RTC_STATUS_REG_POWER_UP_M            0x80
126
127/* RTC_INTERRUPTS_REG bitfields */
128#define BIT_RTC_INTERRUPTS_REG_EVERY_M           0x03
129#define BIT_RTC_INTERRUPTS_REG_IT_TIMER_M        0x04
130#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M        0x08
131
132
133/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
134#define ALL_TIME_REGS		6
135
136/*----------------------------------------------------------------------*/
137static u8  *rtc_reg_map;
138
139/*
140 * Supports 1 byte read from TWL RTC register.
141 */
142static int twl_rtc_read_u8(u8 *data, u8 reg)
143{
144	int ret;
145
146	ret = twl_i2c_read_u8(TWL_MODULE_RTC, data, (rtc_reg_map[reg]));
147	if (ret < 0)
148		pr_err("twl_rtc: Could not read TWL"
149		       "register %X - error %d\n", reg, ret);
150	return ret;
151}
152
153/*
154 * Supports 1 byte write to TWL RTC registers.
155 */
156static int twl_rtc_write_u8(u8 data, u8 reg)
157{
158	int ret;
159
160	ret = twl_i2c_write_u8(TWL_MODULE_RTC, data, (rtc_reg_map[reg]));
161	if (ret < 0)
162		pr_err("twl_rtc: Could not write TWL"
163		       "register %X - error %d\n", reg, ret);
164	return ret;
165}
166
167/*
168 * Cache the value for timer/alarm interrupts register; this is
169 * only changed by callers holding rtc ops lock (or resume).
170 */
171static unsigned char rtc_irq_bits;
172
173/*
174 * Enable 1/second update and/or alarm interrupts.
175 */
176static int set_rtc_irq_bit(unsigned char bit)
177{
178	unsigned char val;
179	int ret;
180
181	/* if the bit is set, return from here */
182	if (rtc_irq_bits & bit)
183		return 0;
184
185	val = rtc_irq_bits | bit;
186	val &= ~BIT_RTC_INTERRUPTS_REG_EVERY_M;
187	ret = twl_rtc_write_u8(val, REG_RTC_INTERRUPTS_REG);
188	if (ret == 0)
189		rtc_irq_bits = val;
190
191	return ret;
192}
193
194/*
195 * Disable update and/or alarm interrupts.
196 */
197static int mask_rtc_irq_bit(unsigned char bit)
198{
199	unsigned char val;
200	int ret;
201
202	/* if the bit is clear, return from here */
203	if (!(rtc_irq_bits & bit))
204		return 0;
205
206	val = rtc_irq_bits & ~bit;
207	ret = twl_rtc_write_u8(val, REG_RTC_INTERRUPTS_REG);
208	if (ret == 0)
209		rtc_irq_bits = val;
210
211	return ret;
212}
213
214static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
215{
216	struct platform_device *pdev = to_platform_device(dev);
217	int irq = platform_get_irq(pdev, 0);
218	static bool twl_rtc_wake_enabled;
219	int ret;
220
221	if (enabled) {
222		ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
223		if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
224			enable_irq_wake(irq);
225			twl_rtc_wake_enabled = true;
226		}
227	} else {
228		ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
229		if (twl_rtc_wake_enabled) {
230			disable_irq_wake(irq);
231			twl_rtc_wake_enabled = false;
232		}
233	}
234
235	return ret;
236}
237
238/*
239 * Gets current TWL RTC time and date parameters.
240 *
241 * The RTC's time/alarm representation is not what gmtime(3) requires
242 * Linux to use:
243 *
244 *  - Months are 1..12 vs Linux 0-11
245 *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
246 */
247static int twl_rtc_read_time(struct device *dev, struct rtc_time *tm)
248{
249	unsigned char rtc_data[ALL_TIME_REGS];
250	int ret;
251	u8 save_control;
252	u8 rtc_control;
253
254	ret = twl_rtc_read_u8(&save_control, REG_RTC_CTRL_REG);
255	if (ret < 0) {
256		dev_err(dev, "%s: reading CTRL_REG, error %d\n", __func__, ret);
257		return ret;
258	}
259	/* for twl6030/32 make sure BIT_RTC_CTRL_REG_GET_TIME_M is clear */
260	if (twl_class_is_6030()) {
261		if (save_control & BIT_RTC_CTRL_REG_GET_TIME_M) {
262			save_control &= ~BIT_RTC_CTRL_REG_GET_TIME_M;
263			ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG);
264			if (ret < 0) {
265				dev_err(dev, "%s clr GET_TIME, error %d\n",
266					__func__, ret);
267				return ret;
268			}
269		}
270	}
271
272	/* Copy RTC counting registers to static registers or latches */
273	rtc_control = save_control | BIT_RTC_CTRL_REG_GET_TIME_M;
274
275	/* for twl6030/32 enable read access to static shadowed registers */
276	if (twl_class_is_6030())
277		rtc_control |= BIT_RTC_CTRL_REG_RTC_V_OPT;
278
279	ret = twl_rtc_write_u8(rtc_control, REG_RTC_CTRL_REG);
280	if (ret < 0) {
281		dev_err(dev, "%s: writing CTRL_REG, error %d\n", __func__, ret);
282		return ret;
283	}
284
285	ret = twl_i2c_read(TWL_MODULE_RTC, rtc_data,
286			(rtc_reg_map[REG_SECONDS_REG]), ALL_TIME_REGS);
287
288	if (ret < 0) {
289		dev_err(dev, "%s: reading data, error %d\n", __func__, ret);
290		return ret;
291	}
292
293	/* for twl6030 restore original state of rtc control register */
294	if (twl_class_is_6030()) {
295		ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG);
296		if (ret < 0) {
297			dev_err(dev, "%s: restore CTRL_REG, error %d\n",
298				__func__, ret);
299			return ret;
300		}
301	}
302
303	tm->tm_sec = bcd2bin(rtc_data[0]);
304	tm->tm_min = bcd2bin(rtc_data[1]);
305	tm->tm_hour = bcd2bin(rtc_data[2]);
306	tm->tm_mday = bcd2bin(rtc_data[3]);
307	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
308	tm->tm_year = bcd2bin(rtc_data[5]) + 100;
309
310	return ret;
311}
312
313static int twl_rtc_set_time(struct device *dev, struct rtc_time *tm)
314{
315	unsigned char save_control;
316	unsigned char rtc_data[ALL_TIME_REGS];
317	int ret;
318
319	rtc_data[0] = bin2bcd(tm->tm_sec);
320	rtc_data[1] = bin2bcd(tm->tm_min);
321	rtc_data[2] = bin2bcd(tm->tm_hour);
322	rtc_data[3] = bin2bcd(tm->tm_mday);
323	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
324	rtc_data[5] = bin2bcd(tm->tm_year - 100);
325
326	/* Stop RTC while updating the TC registers */
327	ret = twl_rtc_read_u8(&save_control, REG_RTC_CTRL_REG);
328	if (ret < 0)
329		goto out;
330
331	save_control &= ~BIT_RTC_CTRL_REG_STOP_RTC_M;
332	ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG);
333	if (ret < 0)
334		goto out;
335
336	/* update all the time registers in one shot */
337	ret = twl_i2c_write(TWL_MODULE_RTC, rtc_data,
338		(rtc_reg_map[REG_SECONDS_REG]), ALL_TIME_REGS);
339	if (ret < 0) {
340		dev_err(dev, "rtc_set_time error %d\n", ret);
341		goto out;
342	}
343
344	/* Start back RTC */
345	save_control |= BIT_RTC_CTRL_REG_STOP_RTC_M;
346	ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG);
347
348out:
349	return ret;
350}
351
352/*
353 * Gets current TWL RTC alarm time.
354 */
355static int twl_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
356{
357	unsigned char rtc_data[ALL_TIME_REGS];
358	int ret;
359
360	ret = twl_i2c_read(TWL_MODULE_RTC, rtc_data,
361			(rtc_reg_map[REG_ALARM_SECONDS_REG]), ALL_TIME_REGS);
362	if (ret < 0) {
363		dev_err(dev, "rtc_read_alarm error %d\n", ret);
364		return ret;
365	}
366
367	/* some of these fields may be wildcard/"match all" */
368	alm->time.tm_sec = bcd2bin(rtc_data[0]);
369	alm->time.tm_min = bcd2bin(rtc_data[1]);
370	alm->time.tm_hour = bcd2bin(rtc_data[2]);
371	alm->time.tm_mday = bcd2bin(rtc_data[3]);
372	alm->time.tm_mon = bcd2bin(rtc_data[4]) - 1;
373	alm->time.tm_year = bcd2bin(rtc_data[5]) + 100;
374
375	/* report cached alarm enable state */
376	if (rtc_irq_bits & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M)
377		alm->enabled = 1;
378
379	return ret;
380}
381
382static int twl_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
383{
384	unsigned char alarm_data[ALL_TIME_REGS];
385	int ret;
386
387	ret = twl_rtc_alarm_irq_enable(dev, 0);
388	if (ret)
389		goto out;
390
391	alarm_data[0] = bin2bcd(alm->time.tm_sec);
392	alarm_data[1] = bin2bcd(alm->time.tm_min);
393	alarm_data[2] = bin2bcd(alm->time.tm_hour);
394	alarm_data[3] = bin2bcd(alm->time.tm_mday);
395	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
396	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
397
398	/* update all the alarm registers in one shot */
399	ret = twl_i2c_write(TWL_MODULE_RTC, alarm_data,
400		(rtc_reg_map[REG_ALARM_SECONDS_REG]), ALL_TIME_REGS);
401	if (ret) {
402		dev_err(dev, "rtc_set_alarm error %d\n", ret);
403		goto out;
404	}
405
406	if (alm->enabled)
407		ret = twl_rtc_alarm_irq_enable(dev, 1);
408out:
409	return ret;
410}
411
412static irqreturn_t twl_rtc_interrupt(int irq, void *rtc)
413{
414	unsigned long events;
415	int ret = IRQ_NONE;
416	int res;
417	u8 rd_reg;
418
419	res = twl_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG);
420	if (res)
421		goto out;
422	/*
423	 * Figure out source of interrupt: ALARM or TIMER in RTC_STATUS_REG.
424	 * only one (ALARM or RTC) interrupt source may be enabled
425	 * at time, we also could check our results
426	 * by reading RTS_INTERRUPTS_REGISTER[IT_TIMER,IT_ALARM]
427	 */
428	if (rd_reg & BIT_RTC_STATUS_REG_ALARM_M)
429		events = RTC_IRQF | RTC_AF;
430	else
431		events = RTC_IRQF | RTC_PF;
432
433	res = twl_rtc_write_u8(BIT_RTC_STATUS_REG_ALARM_M,
434				   REG_RTC_STATUS_REG);
435	if (res)
436		goto out;
437
438	if (twl_class_is_4030()) {
439		/* Clear on Read enabled. RTC_IT bit of TWL4030_INT_PWR_ISR1
440		 * needs 2 reads to clear the interrupt. One read is done in
441		 * do_twl_pwrirq(). Doing the second read, to clear
442		 * the bit.
443		 *
444		 * FIXME the reason PWR_ISR1 needs an extra read is that
445		 * RTC_IF retriggered until we cleared REG_ALARM_M above.
446		 * But re-reading like this is a bad hack; by doing so we
447		 * risk wrongly clearing status for some other IRQ (losing
448		 * the interrupt).  Be smarter about handling RTC_UF ...
449		 */
450		res = twl_i2c_read_u8(TWL4030_MODULE_INT,
451			&rd_reg, TWL4030_INT_PWR_ISR1);
452		if (res)
453			goto out;
454	}
455
456	/* Notify RTC core on event */
457	rtc_update_irq(rtc, 1, events);
458
459	ret = IRQ_HANDLED;
460out:
461	return ret;
462}
463
464static struct rtc_class_ops twl_rtc_ops = {
465	.read_time	= twl_rtc_read_time,
466	.set_time	= twl_rtc_set_time,
467	.read_alarm	= twl_rtc_read_alarm,
468	.set_alarm	= twl_rtc_set_alarm,
469	.alarm_irq_enable = twl_rtc_alarm_irq_enable,
470};
471
472/*----------------------------------------------------------------------*/
473
474static int twl_rtc_probe(struct platform_device *pdev)
475{
476	struct rtc_device *rtc;
477	int ret = -EINVAL;
478	int irq = platform_get_irq(pdev, 0);
479	u8 rd_reg;
480
481	if (irq <= 0)
482		return ret;
483
484	/* Initialize the register map */
485	if (twl_class_is_4030())
486		rtc_reg_map = (u8 *)twl4030_rtc_reg_map;
487	else
488		rtc_reg_map = (u8 *)twl6030_rtc_reg_map;
489
490	ret = twl_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG);
491	if (ret < 0)
492		return ret;
493
494	if (rd_reg & BIT_RTC_STATUS_REG_POWER_UP_M)
495		dev_warn(&pdev->dev, "Power up reset detected.\n");
496
497	if (rd_reg & BIT_RTC_STATUS_REG_ALARM_M)
498		dev_warn(&pdev->dev, "Pending Alarm interrupt detected.\n");
499
500	/* Clear RTC Power up reset and pending alarm interrupts */
501	ret = twl_rtc_write_u8(rd_reg, REG_RTC_STATUS_REG);
502	if (ret < 0)
503		return ret;
504
505	if (twl_class_is_6030()) {
506		twl6030_interrupt_unmask(TWL6030_RTC_INT_MASK,
507			REG_INT_MSK_LINE_A);
508		twl6030_interrupt_unmask(TWL6030_RTC_INT_MASK,
509			REG_INT_MSK_STS_A);
510	}
511
512	dev_info(&pdev->dev, "Enabling TWL-RTC\n");
513	ret = twl_rtc_write_u8(BIT_RTC_CTRL_REG_STOP_RTC_M, REG_RTC_CTRL_REG);
514	if (ret < 0)
515		return ret;
516
517	/* ensure interrupts are disabled, bootloaders can be strange */
518	ret = twl_rtc_write_u8(0, REG_RTC_INTERRUPTS_REG);
519	if (ret < 0)
520		dev_warn(&pdev->dev, "unable to disable interrupt\n");
521
522	/* init cached IRQ enable bits */
523	ret = twl_rtc_read_u8(&rtc_irq_bits, REG_RTC_INTERRUPTS_REG);
524	if (ret < 0)
525		return ret;
526
527	device_init_wakeup(&pdev->dev, 1);
528
529	rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
530					&twl_rtc_ops, THIS_MODULE);
531	if (IS_ERR(rtc)) {
532		dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
533			PTR_ERR(rtc));
534		return PTR_ERR(rtc);
535	}
536
537	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
538					twl_rtc_interrupt,
539					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
540					dev_name(&rtc->dev), rtc);
541	if (ret < 0) {
542		dev_err(&pdev->dev, "IRQ is not free.\n");
543		return ret;
544	}
545
546	platform_set_drvdata(pdev, rtc);
547	return 0;
548}
549
550/*
551 * Disable all TWL RTC module interrupts.
552 * Sets status flag to free.
553 */
554static int twl_rtc_remove(struct platform_device *pdev)
555{
556	/* leave rtc running, but disable irqs */
557	mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
558	mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M);
559	if (twl_class_is_6030()) {
560		twl6030_interrupt_mask(TWL6030_RTC_INT_MASK,
561			REG_INT_MSK_LINE_A);
562		twl6030_interrupt_mask(TWL6030_RTC_INT_MASK,
563			REG_INT_MSK_STS_A);
564	}
565
566	return 0;
567}
568
569static void twl_rtc_shutdown(struct platform_device *pdev)
570{
571	/* mask timer interrupts, but leave alarm interrupts on to enable
572	   power-on when alarm is triggered */
573	mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M);
574}
575
576#ifdef CONFIG_PM_SLEEP
577static unsigned char irqstat;
578
579static int twl_rtc_suspend(struct device *dev)
580{
581	irqstat = rtc_irq_bits;
582
583	mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M);
584	return 0;
585}
586
587static int twl_rtc_resume(struct device *dev)
588{
589	set_rtc_irq_bit(irqstat);
590	return 0;
591}
592#endif
593
594static SIMPLE_DEV_PM_OPS(twl_rtc_pm_ops, twl_rtc_suspend, twl_rtc_resume);
595
596#ifdef CONFIG_OF
597static const struct of_device_id twl_rtc_of_match[] = {
598	{.compatible = "ti,twl4030-rtc", },
599	{ },
600};
601MODULE_DEVICE_TABLE(of, twl_rtc_of_match);
602#endif
603
604MODULE_ALIAS("platform:twl_rtc");
605
606static struct platform_driver twl4030rtc_driver = {
607	.probe		= twl_rtc_probe,
608	.remove		= twl_rtc_remove,
609	.shutdown	= twl_rtc_shutdown,
610	.driver		= {
611		.owner		= THIS_MODULE,
612		.name		= "twl_rtc",
613		.pm		= &twl_rtc_pm_ops,
614		.of_match_table = of_match_ptr(twl_rtc_of_match),
615	},
616};
617
618module_platform_driver(twl4030rtc_driver);
619
620MODULE_AUTHOR("Texas Instruments, MontaVista Software");
621MODULE_LICENSE("GPL");
622