1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * rtc-tps65910.c -- TPS65910 Real Time Clock interface
  4 *
  5 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
  6 * Author: Venu Byravarasu <vbyravarasu@nvidia.com>
  7 *
  8 * Based on original TI driver rtc-twl.c
  9 *   Copyright (C) 2007 MontaVista Software, Inc
 10 *   Author: Alexandre Rusev <source@mvista.com>
 11 */
 12
 13#include <linux/kernel.h>
 14#include <linux/errno.h>
 15#include <linux/init.h>
 16#include <linux/module.h>
 17#include <linux/types.h>
 18#include <linux/rtc.h>
 19#include <linux/bcd.h>
 20#include <linux/math64.h>
 21#include <linux/platform_device.h>
 22#include <linux/interrupt.h>
 23#include <linux/mfd/tps65910.h>
 24
 25struct tps65910_rtc {
 26	struct rtc_device	*rtc;
 27	int irq;
 28};
 29
 30/* Total number of RTC registers needed to set time*/
 31#define NUM_TIME_REGS	(TPS65910_YEARS - TPS65910_SECONDS + 1)
 32
 33/* Total number of RTC registers needed to set compensation registers */
 34#define NUM_COMP_REGS	(TPS65910_RTC_COMP_MSB - TPS65910_RTC_COMP_LSB + 1)
 35
 36/* Min and max values supported with 'offset' interface (swapped sign) */
 37#define MIN_OFFSET	(-277761)
 38#define MAX_OFFSET	(277778)
 39
 40/* Number of ticks per hour */
 41#define TICKS_PER_HOUR	(32768 * 3600)
 42
 43/* Multiplier for ppb conversions */
 44#define PPB_MULT	(1000000000LL)
 45
 46static int tps65910_rtc_alarm_irq_enable(struct device *dev,
 47					 unsigned int enabled)
 48{
 49	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 50	u8 val = 0;
 51
 52	if (enabled)
 53		val = TPS65910_RTC_INTERRUPTS_IT_ALARM;
 54
 55	return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
 56}
 57
 58/*
 59 * Gets current tps65910 RTC time and date parameters.
 60 *
 61 * The RTC's time/alarm representation is not what gmtime(3) requires
 62 * Linux to use:
 63 *
 64 *  - Months are 1..12 vs Linux 0-11
 65 *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
 66 */
 67static int tps65910_rtc_read_time(struct device *dev, struct rtc_time *tm)
 68{
 69	unsigned char rtc_data[NUM_TIME_REGS];
 70	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 71	int ret;
 72
 73	/* Copy RTC counting registers to static registers or latches */
 74	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 75		TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
 76	if (ret < 0) {
 77		dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
 78		return ret;
 79	}
 80
 81	ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
 82		NUM_TIME_REGS);
 83	if (ret < 0) {
 84		dev_err(dev, "reading from RTC failed with err:%d\n", ret);
 85		return ret;
 86	}
 87
 88	tm->tm_sec = bcd2bin(rtc_data[0]);
 89	tm->tm_min = bcd2bin(rtc_data[1]);
 90	tm->tm_hour = bcd2bin(rtc_data[2]);
 91	tm->tm_mday = bcd2bin(rtc_data[3]);
 92	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
 93	tm->tm_year = bcd2bin(rtc_data[5]) + 100;
 94
 95	return ret;
 96}
 97
 98static int tps65910_rtc_set_time(struct device *dev, struct rtc_time *tm)
 99{
100	unsigned char rtc_data[NUM_TIME_REGS];
101	struct tps65910 *tps = dev_get_drvdata(dev->parent);
102	int ret;
103
104	rtc_data[0] = bin2bcd(tm->tm_sec);
105	rtc_data[1] = bin2bcd(tm->tm_min);
106	rtc_data[2] = bin2bcd(tm->tm_hour);
107	rtc_data[3] = bin2bcd(tm->tm_mday);
108	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
109	rtc_data[5] = bin2bcd(tm->tm_year - 100);
110
111	/* Stop RTC while updating the RTC time registers */
112	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
113		TPS65910_RTC_CTRL_STOP_RTC, 0);
114	if (ret < 0) {
115		dev_err(dev, "RTC stop failed with err:%d\n", ret);
116		return ret;
117	}
118
119	/* update all the time registers in one shot */
120	ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
121		NUM_TIME_REGS);
122	if (ret < 0) {
123		dev_err(dev, "rtc_set_time error %d\n", ret);
124		return ret;
125	}
126
127	/* Start back RTC */
128	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
129		TPS65910_RTC_CTRL_STOP_RTC, 1);
130	if (ret < 0)
131		dev_err(dev, "RTC start failed with err:%d\n", ret);
132
133	return ret;
134}
135
136/*
137 * Gets current tps65910 RTC alarm time.
138 */
139static int tps65910_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
140{
141	unsigned char alarm_data[NUM_TIME_REGS];
142	u32 int_val;
143	struct tps65910 *tps = dev_get_drvdata(dev->parent);
144	int ret;
145
146	ret = regmap_bulk_read(tps->regmap, TPS65910_ALARM_SECONDS, alarm_data,
147		NUM_TIME_REGS);
148	if (ret < 0) {
149		dev_err(dev, "rtc_read_alarm error %d\n", ret);
150		return ret;
151	}
152
153	alm->time.tm_sec = bcd2bin(alarm_data[0]);
154	alm->time.tm_min = bcd2bin(alarm_data[1]);
155	alm->time.tm_hour = bcd2bin(alarm_data[2]);
156	alm->time.tm_mday = bcd2bin(alarm_data[3]);
157	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
158	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
159
160	ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
161	if (ret < 0)
162		return ret;
163
164	if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
165		alm->enabled = 1;
166
167	return ret;
168}
169
170static int tps65910_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
171{
172	unsigned char alarm_data[NUM_TIME_REGS];
173	struct tps65910 *tps = dev_get_drvdata(dev->parent);
174	int ret;
175
176	ret = tps65910_rtc_alarm_irq_enable(dev, 0);
177	if (ret)
178		return ret;
179
180	alarm_data[0] = bin2bcd(alm->time.tm_sec);
181	alarm_data[1] = bin2bcd(alm->time.tm_min);
182	alarm_data[2] = bin2bcd(alm->time.tm_hour);
183	alarm_data[3] = bin2bcd(alm->time.tm_mday);
184	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
185	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
186
187	/* update all the alarm registers in one shot */
188	ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
189		alarm_data, NUM_TIME_REGS);
190	if (ret) {
191		dev_err(dev, "rtc_set_alarm error %d\n", ret);
192		return ret;
193	}
194
195	if (alm->enabled)
196		ret = tps65910_rtc_alarm_irq_enable(dev, 1);
197
198	return ret;
199}
200
201static int tps65910_rtc_set_calibration(struct device *dev, int calibration)
202{
203	unsigned char comp_data[NUM_COMP_REGS];
204	struct tps65910 *tps = dev_get_drvdata(dev->parent);
205	s16 value;
206	int ret;
207
208	/*
209	 * TPS65910 uses two's complement 16 bit value for compensation for RTC
210	 * crystal inaccuracies. One time every hour when seconds counter
211	 * increments from 0 to 1 compensation value will be added to internal
212	 * RTC counter value.
213	 *
214	 * Compensation value 0x7FFF is prohibited value.
215	 *
216	 * Valid range for compensation value: [-32768 .. 32766]
217	 */
218	if ((calibration < -32768) || (calibration > 32766)) {
219		dev_err(dev, "RTC calibration value out of range: %d\n",
220			calibration);
221		return -EINVAL;
222	}
223
224	value = (s16)calibration;
225
226	comp_data[0] = (u16)value & 0xFF;
227	comp_data[1] = ((u16)value >> 8) & 0xFF;
228
229	/* Update all the compensation registers in one shot */
230	ret = regmap_bulk_write(tps->regmap, TPS65910_RTC_COMP_LSB,
231		comp_data, NUM_COMP_REGS);
232	if (ret < 0) {
233		dev_err(dev, "rtc_set_calibration error: %d\n", ret);
234		return ret;
235	}
236
237	/* Enable automatic compensation */
238	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
239		TPS65910_RTC_CTRL_AUTO_COMP, TPS65910_RTC_CTRL_AUTO_COMP);
240	if (ret < 0)
241		dev_err(dev, "auto_comp enable failed with error: %d\n", ret);
242
243	return ret;
244}
245
246static int tps65910_rtc_get_calibration(struct device *dev, int *calibration)
247{
248	unsigned char comp_data[NUM_COMP_REGS];
249	struct tps65910 *tps = dev_get_drvdata(dev->parent);
250	unsigned int ctrl;
251	u16 value;
252	int ret;
253
254	ret = regmap_read(tps->regmap, TPS65910_RTC_CTRL, &ctrl);
255	if (ret < 0)
256		return ret;
257
258	/* If automatic compensation is not enabled report back zero */
259	if (!(ctrl & TPS65910_RTC_CTRL_AUTO_COMP)) {
260		*calibration = 0;
261		return 0;
262	}
263
264	ret = regmap_bulk_read(tps->regmap, TPS65910_RTC_COMP_LSB, comp_data,
265		NUM_COMP_REGS);
266	if (ret < 0) {
267		dev_err(dev, "rtc_get_calibration error: %d\n", ret);
268		return ret;
269	}
270
271	value = (u16)comp_data[0] | ((u16)comp_data[1] << 8);
272
273	*calibration = (s16)value;
274
275	return 0;
276}
277
278static int tps65910_read_offset(struct device *dev, long *offset)
279{
280	int calibration;
281	s64 tmp;
282	int ret;
283
284	ret = tps65910_rtc_get_calibration(dev, &calibration);
285	if (ret < 0)
286		return ret;
287
288	/* Convert from RTC calibration register format to ppb format */
289	tmp = calibration * (s64)PPB_MULT;
290	if (tmp < 0)
291		tmp -= TICKS_PER_HOUR / 2LL;
292	else
293		tmp += TICKS_PER_HOUR / 2LL;
294	tmp = div_s64(tmp, TICKS_PER_HOUR);
295
296	/* Offset value operates in negative way, so swap sign */
297	*offset = (long)-tmp;
298
299	return 0;
300}
301
302static int tps65910_set_offset(struct device *dev, long offset)
303{
304	int calibration;
305	s64 tmp;
306	int ret;
307
308	/* Make sure offset value is within supported range */
309	if (offset < MIN_OFFSET || offset > MAX_OFFSET)
310		return -ERANGE;
311
312	/* Convert from ppb format to RTC calibration register format */
313	tmp = offset * (s64)TICKS_PER_HOUR;
314	if (tmp < 0)
315		tmp -= PPB_MULT / 2LL;
316	else
317		tmp += PPB_MULT / 2LL;
318	tmp = div_s64(tmp, PPB_MULT);
319
320	/* Offset value operates in negative way, so swap sign */
321	calibration = (int)-tmp;
322
323	ret = tps65910_rtc_set_calibration(dev, calibration);
324
325	return ret;
326}
327
328static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
329{
330	struct device *dev = rtc;
331	unsigned long events = 0;
332	struct tps65910 *tps = dev_get_drvdata(dev->parent);
333	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
334	int ret;
335	u32 rtc_reg;
336
337	ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
338	if (ret)
339		return IRQ_NONE;
340
341	if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
342		events = RTC_IRQF | RTC_AF;
343
344	ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
345	if (ret)
346		return IRQ_NONE;
347
348	/* Notify RTC core on event */
349	rtc_update_irq(tps_rtc->rtc, 1, events);
350
351	return IRQ_HANDLED;
352}
353
354static const struct rtc_class_ops tps65910_rtc_ops = {
355	.read_time	= tps65910_rtc_read_time,
356	.set_time	= tps65910_rtc_set_time,
357	.read_alarm	= tps65910_rtc_read_alarm,
358	.set_alarm	= tps65910_rtc_set_alarm,
359	.alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
360	.read_offset	= tps65910_read_offset,
361	.set_offset	= tps65910_set_offset,
362};
363
364static int tps65910_rtc_probe(struct platform_device *pdev)
365{
366	struct tps65910 *tps65910 = NULL;
367	struct tps65910_rtc *tps_rtc = NULL;
368	int ret;
369	int irq;
370	u32 rtc_reg;
371
372	tps65910 = dev_get_drvdata(pdev->dev.parent);
373
374	tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
375			GFP_KERNEL);
376	if (!tps_rtc)
377		return -ENOMEM;
378
379	tps_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
380	if (IS_ERR(tps_rtc->rtc))
381		return PTR_ERR(tps_rtc->rtc);
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->ops = &tps65910_rtc_ops;
425	tps_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
426	tps_rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;
427
428	return rtc_register_device(tps_rtc->rtc);
429}
430
431#ifdef CONFIG_PM_SLEEP
432static int tps65910_rtc_suspend(struct device *dev)
433{
434	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
435
436	if (device_may_wakeup(dev))
437		enable_irq_wake(tps_rtc->irq);
438	return 0;
439}
440
441static int tps65910_rtc_resume(struct device *dev)
442{
443	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
444
445	if (device_may_wakeup(dev))
446		disable_irq_wake(tps_rtc->irq);
447	return 0;
448}
449#endif
450
451static SIMPLE_DEV_PM_OPS(tps65910_rtc_pm_ops, tps65910_rtc_suspend,
452			tps65910_rtc_resume);
453
454static struct platform_driver tps65910_rtc_driver = {
455	.probe		= tps65910_rtc_probe,
456	.driver		= {
457		.name	= "tps65910-rtc",
458		.pm	= &tps65910_rtc_pm_ops,
459	},
460};
461
462module_platform_driver(tps65910_rtc_driver);
463MODULE_ALIAS("platform:rtc-tps65910");
464MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
465MODULE_LICENSE("GPL");