1/*
  2 * rtc-tps65910.c -- TPS65910 Real Time Clock interface
  3 *
  4 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
  5 * Author: Venu Byravarasu <vbyravarasu@nvidia.com>
  6 *
  7 * Based on original TI driver rtc-twl.c
  8 *   Copyright (C) 2007 MontaVista Software, Inc
  9 *   Author: Alexandre Rusev <source@mvista.com>
 10 *
 11 * This program is free software; you can redistribute it and/or
 12 * modify it under the terms of the GNU General Public License
 13 * as published by the Free Software Foundation; either version
 14 * 2 of the License, or (at your option) any later version.
 15 */
 16
 17#include <linux/kernel.h>
 18#include <linux/errno.h>
 19#include <linux/init.h>
 20#include <linux/module.h>
 21#include <linux/types.h>
 22#include <linux/rtc.h>
 23#include <linux/bcd.h>
 24#include <linux/math64.h>
 25#include <linux/platform_device.h>
 26#include <linux/interrupt.h>
 27#include <linux/mfd/tps65910.h>
 28
 29struct tps65910_rtc {
 30	struct rtc_device	*rtc;
 31	int irq;
 32};
 33
 34/* Total number of RTC registers needed to set time*/
 35#define NUM_TIME_REGS	(TPS65910_YEARS - TPS65910_SECONDS + 1)
 36
 37/* Total number of RTC registers needed to set compensation registers */
 38#define NUM_COMP_REGS	(TPS65910_RTC_COMP_MSB - TPS65910_RTC_COMP_LSB + 1)
 39
 40/* Min and max values supported with 'offset' interface (swapped sign) */
 41#define MIN_OFFSET	(-277761)
 42#define MAX_OFFSET	(277778)
 43
 44/* Number of ticks per hour */
 45#define TICKS_PER_HOUR	(32768 * 3600)
 46
 47/* Multiplier for ppb conversions */
 48#define PPB_MULT	(1000000000LL)
 49
 50static int tps65910_rtc_alarm_irq_enable(struct device *dev,
 51					 unsigned int enabled)
 52{
 53	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 54	u8 val = 0;
 55
 56	if (enabled)
 57		val = TPS65910_RTC_INTERRUPTS_IT_ALARM;
 58
 59	return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
 60}
 61
 62/*
 63 * Gets current tps65910 RTC time and date parameters.
 64 *
 65 * The RTC's time/alarm representation is not what gmtime(3) requires
 66 * Linux to use:
 67 *
 68 *  - Months are 1..12 vs Linux 0-11
 69 *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
 70 */
 71static int tps65910_rtc_read_time(struct device *dev, struct rtc_time *tm)
 72{
 73	unsigned char rtc_data[NUM_TIME_REGS];
 74	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 75	int ret;
 76
 77	/* Copy RTC counting registers to static registers or latches */
 78	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 79		TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
 80	if (ret < 0) {
 81		dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
 82		return ret;
 83	}
 84
 85	ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
 86		NUM_TIME_REGS);
 87	if (ret < 0) {
 88		dev_err(dev, "reading from RTC failed with err:%d\n", ret);
 89		return ret;
 90	}
 91
 92	tm->tm_sec = bcd2bin(rtc_data[0]);
 93	tm->tm_min = bcd2bin(rtc_data[1]);
 94	tm->tm_hour = bcd2bin(rtc_data[2]);
 95	tm->tm_mday = bcd2bin(rtc_data[3]);
 96	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
 97	tm->tm_year = bcd2bin(rtc_data[5]) + 100;
 98
 99	return ret;
100}
101
102static int tps65910_rtc_set_time(struct device *dev, struct rtc_time *tm)
103{
104	unsigned char rtc_data[NUM_TIME_REGS];
105	struct tps65910 *tps = dev_get_drvdata(dev->parent);
106	int ret;
107
108	rtc_data[0] = bin2bcd(tm->tm_sec);
109	rtc_data[1] = bin2bcd(tm->tm_min);
110	rtc_data[2] = bin2bcd(tm->tm_hour);
111	rtc_data[3] = bin2bcd(tm->tm_mday);
112	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
113	rtc_data[5] = bin2bcd(tm->tm_year - 100);
114
115	/* Stop RTC while updating the RTC time registers */
116	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
117		TPS65910_RTC_CTRL_STOP_RTC, 0);
118	if (ret < 0) {
119		dev_err(dev, "RTC stop failed with err:%d\n", ret);
120		return ret;
121	}
122
123	/* update all the time registers in one shot */
124	ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
125		NUM_TIME_REGS);
126	if (ret < 0) {
127		dev_err(dev, "rtc_set_time error %d\n", ret);
128		return ret;
129	}
130
131	/* Start back RTC */
132	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
133		TPS65910_RTC_CTRL_STOP_RTC, 1);
134	if (ret < 0)
135		dev_err(dev, "RTC start failed with err:%d\n", ret);
136
137	return ret;
138}
139
140/*
141 * Gets current tps65910 RTC alarm time.
142 */
143static int tps65910_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
144{
145	unsigned char alarm_data[NUM_TIME_REGS];
146	u32 int_val;
147	struct tps65910 *tps = dev_get_drvdata(dev->parent);
148	int ret;
149
150	ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, alarm_data,
151		NUM_TIME_REGS);
152	if (ret < 0) {
153		dev_err(dev, "rtc_read_alarm error %d\n", ret);
154		return ret;
155	}
156
157	alm->time.tm_sec = bcd2bin(alarm_data[0]);
158	alm->time.tm_min = bcd2bin(alarm_data[1]);
159	alm->time.tm_hour = bcd2bin(alarm_data[2]);
160	alm->time.tm_mday = bcd2bin(alarm_data[3]);
161	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
162	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
163
164	ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
165	if (ret < 0)
166		return ret;
167
168	if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
169		alm->enabled = 1;
170
171	return ret;
172}
173
174static int tps65910_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
175{
176	unsigned char alarm_data[NUM_TIME_REGS];
177	struct tps65910 *tps = dev_get_drvdata(dev->parent);
178	int ret;
179
180	ret = tps65910_rtc_alarm_irq_enable(dev, 0);
181	if (ret)
182		return ret;
183
184	alarm_data[0] = bin2bcd(alm->time.tm_sec);
185	alarm_data[1] = bin2bcd(alm->time.tm_min);
186	alarm_data[2] = bin2bcd(alm->time.tm_hour);
187	alarm_data[3] = bin2bcd(alm->time.tm_mday);
188	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
189	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
190
191	/* update all the alarm registers in one shot */
192	ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
193		alarm_data, NUM_TIME_REGS);
194	if (ret) {
195		dev_err(dev, "rtc_set_alarm error %d\n", ret);
196		return ret;
197	}
198
199	if (alm->enabled)
200		ret = tps65910_rtc_alarm_irq_enable(dev, 1);
201
202	return ret;
203}
204
205static int tps65910_rtc_set_calibration(struct device *dev, int calibration)
206{
207	unsigned char comp_data[NUM_COMP_REGS];
208	struct tps65910 *tps = dev_get_drvdata(dev->parent);
209	s16 value;
210	int ret;
211
212	/*
213	 * TPS65910 uses two's complement 16 bit value for compensation for RTC
214	 * crystal inaccuracies. One time every hour when seconds counter
215	 * increments from 0 to 1 compensation value will be added to internal
216	 * RTC counter value.
217	 *
218	 * Compensation value 0x7FFF is prohibited value.
219	 *
220	 * Valid range for compensation value: [-32768 .. 32766]
221	 */
222	if ((calibration < -32768) || (calibration > 32766)) {
223		dev_err(dev, "RTC calibration value out of range: %d\n",
224			calibration);
225		return -EINVAL;
226	}
227
228	value = (s16)calibration;
229
230	comp_data[0] = (u16)value & 0xFF;
231	comp_data[1] = ((u16)value >> 8) & 0xFF;
232
233	/* Update all the compensation registers in one shot */
234	ret = regmap_bulk_write(tps->regmap, TPS65910_RTC_COMP_LSB,
235		comp_data, NUM_COMP_REGS);
236	if (ret < 0) {
237		dev_err(dev, "rtc_set_calibration error: %d\n", ret);
238		return ret;
239	}
240
241	/* Enable automatic compensation */
242	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
243		TPS65910_RTC_CTRL_AUTO_COMP, TPS65910_RTC_CTRL_AUTO_COMP);
244	if (ret < 0)
245		dev_err(dev, "auto_comp enable failed with error: %d\n", ret);
246
247	return ret;
248}
249
250static int tps65910_rtc_get_calibration(struct device *dev, int *calibration)
251{
252	unsigned char comp_data[NUM_COMP_REGS];
253	struct tps65910 *tps = dev_get_drvdata(dev->parent);
254	unsigned int ctrl;
255	u16 value;
256	int ret;
257
258	ret = regmap_read(tps->regmap, TPS65910_RTC_CTRL, &ctrl);
259	if (ret < 0)
260		return ret;
261
262	/* If automatic compensation is not enabled report back zero */
263	if (!(ctrl & TPS65910_RTC_CTRL_AUTO_COMP)) {
264		*calibration = 0;
265		return 0;
266	}
267
268	ret = regmap_bulk_read(tps->regmap, TPS65910_RTC_COMP_LSB, comp_data,
269		NUM_COMP_REGS);
270	if (ret < 0) {
271		dev_err(dev, "rtc_get_calibration error: %d\n", ret);
272		return ret;
273	}
274
275	value = (u16)comp_data[0] | ((u16)comp_data[1] << 8);
276
277	*calibration = (s16)value;
278
279	return 0;
280}
281
282static int tps65910_read_offset(struct device *dev, long *offset)
283{
284	int calibration;
285	s64 tmp;
286	int ret;
287
288	ret = tps65910_rtc_get_calibration(dev, &calibration);
289	if (ret < 0)
290		return ret;
291
292	/* Convert from RTC calibration register format to ppb format */
293	tmp = calibration * (s64)PPB_MULT;
294	if (tmp < 0)
295		tmp -= TICKS_PER_HOUR / 2LL;
296	else
297		tmp += TICKS_PER_HOUR / 2LL;
298	tmp = div_s64(tmp, TICKS_PER_HOUR);
299
300	/* Offset value operates in negative way, so swap sign */
301	*offset = (long)-tmp;
302
303	return 0;
304}
305
306static int tps65910_set_offset(struct device *dev, long offset)
307{
308	int calibration;
309	s64 tmp;
310	int ret;
311
312	/* Make sure offset value is within supported range */
313	if (offset < MIN_OFFSET || offset > MAX_OFFSET)
314		return -ERANGE;
315
316	/* Convert from ppb format to RTC calibration register format */
317	tmp = offset * (s64)TICKS_PER_HOUR;
318	if (tmp < 0)
319		tmp -= PPB_MULT / 2LL;
320	else
321		tmp += PPB_MULT / 2LL;
322	tmp = div_s64(tmp, PPB_MULT);
323
324	/* Offset value operates in negative way, so swap sign */
325	calibration = (int)-tmp;
326
327	ret = tps65910_rtc_set_calibration(dev, calibration);
328
329	return ret;
330}
331
332static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
333{
334	struct device *dev = rtc;
335	unsigned long events = 0;
336	struct tps65910 *tps = dev_get_drvdata(dev->parent);
337	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
338	int ret;
339	u32 rtc_reg;
340
341	ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
342	if (ret)
343		return IRQ_NONE;
344
345	if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
346		events = RTC_IRQF | RTC_AF;
347
348	ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
349	if (ret)
350		return IRQ_NONE;
351
352	/* Notify RTC core on event */
353	rtc_update_irq(tps_rtc->rtc, 1, events);
354
355	return IRQ_HANDLED;
356}
357
358static const struct rtc_class_ops tps65910_rtc_ops = {
359	.read_time	= tps65910_rtc_read_time,
360	.set_time	= tps65910_rtc_set_time,
361	.read_alarm	= tps65910_rtc_read_alarm,
362	.set_alarm	= tps65910_rtc_set_alarm,
363	.alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
364	.read_offset	= tps65910_read_offset,
365	.set_offset	= tps65910_set_offset,
366};
367
368static int tps65910_rtc_probe(struct platform_device *pdev)
369{
370	struct tps65910 *tps65910 = NULL;
371	struct tps65910_rtc *tps_rtc = NULL;
372	int ret;
373	int irq;
374	u32 rtc_reg;
375
376	tps65910 = dev_get_drvdata(pdev->dev.parent);
377
378	tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
379			GFP_KERNEL);
380	if (!tps_rtc)
381		return -ENOMEM;
382
383	/* Clear pending interrupts */
384	ret = regmap_read(tps65910->regmap, TPS65910_RTC_STATUS, &rtc_reg);
385	if (ret < 0)
386		return ret;
387
388	ret = regmap_write(tps65910->regmap, TPS65910_RTC_STATUS, rtc_reg);
389	if (ret < 0)
390		return ret;
391
392	dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n");
393
394	/* Enable RTC digital power domain */
395	ret = regmap_update_bits(tps65910->regmap, TPS65910_DEVCTRL,
396		DEVCTRL_RTC_PWDN_MASK, 0 << DEVCTRL_RTC_PWDN_SHIFT);
397	if (ret < 0)
398		return ret;
399
400	rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
401	ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
402	if (ret < 0)
403		return ret;
404
405	platform_set_drvdata(pdev, tps_rtc);
406
407	irq  = platform_get_irq(pdev, 0);
408	if (irq <= 0) {
409		dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
410			irq);
411		return -ENXIO;
412	}
413
414	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
415		tps65910_rtc_interrupt, IRQF_TRIGGER_LOW,
416		dev_name(&pdev->dev), &pdev->dev);
417	if (ret < 0) {
418		dev_err(&pdev->dev, "IRQ is not free.\n");
419		return ret;
420	}
421	tps_rtc->irq = irq;
422	device_set_wakeup_capable(&pdev->dev, 1);
423
424	tps_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
425		&tps65910_rtc_ops, THIS_MODULE);
426	if (IS_ERR(tps_rtc->rtc)) {
427		ret = PTR_ERR(tps_rtc->rtc);
428		dev_err(&pdev->dev, "RTC device register: err %d\n", ret);
429		return ret;
430	}
431
432	return 0;
433}
434
435/*
436 * Disable tps65910 RTC interrupts.
437 * Sets status flag to free.
438 */
439static int tps65910_rtc_remove(struct platform_device *pdev)
440{
441	tps65910_rtc_alarm_irq_enable(&pdev->dev, 0);
442
443	return 0;
444}
445
446#ifdef CONFIG_PM_SLEEP
447static int tps65910_rtc_suspend(struct device *dev)
448{
449	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
450
451	if (device_may_wakeup(dev))
452		enable_irq_wake(tps_rtc->irq);
453	return 0;
454}
455
456static int tps65910_rtc_resume(struct device *dev)
457{
458	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
459
460	if (device_may_wakeup(dev))
461		disable_irq_wake(tps_rtc->irq);
462	return 0;
463}
464#endif
465
466static SIMPLE_DEV_PM_OPS(tps65910_rtc_pm_ops, tps65910_rtc_suspend,
467			tps65910_rtc_resume);
468
469static struct platform_driver tps65910_rtc_driver = {
470	.probe		= tps65910_rtc_probe,
471	.remove		= tps65910_rtc_remove,
472	.driver		= {
473		.name	= "tps65910-rtc",
474		.pm	= &tps65910_rtc_pm_ops,
475	},
476};
477
478module_platform_driver(tps65910_rtc_driver);
479MODULE_ALIAS("platform:rtc-tps65910");
480MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
481MODULE_LICENSE("GPL");