rtc-pl031.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * drivers/rtc/rtc-pl031.c
  4 *
  5 * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
  6 *
  7 * Author: Deepak Saxena <dsaxena@plexity.net>
  8 *
  9 * Copyright 2006 (c) MontaVista Software, Inc.
 10 *
 11 * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
 12 * Copyright 2010 (c) ST-Ericsson AB
 13 */
 14#include <linux/module.h>
 15#include <linux/rtc.h>
 16#include <linux/init.h>
 17#include <linux/interrupt.h>
 18#include <linux/amba/bus.h>
 19#include <linux/io.h>
 20#include <linux/bcd.h>
 21#include <linux/delay.h>
 22#include <linux/pm_wakeirq.h>
 23#include <linux/slab.h>
 24
 25/*
 26 * Register definitions
 27 */
 28#define	RTC_DR		0x00	/* Data read register */
 29#define	RTC_MR		0x04	/* Match register */
 30#define	RTC_LR		0x08	/* Data load register */
 31#define	RTC_CR		0x0c	/* Control register */
 32#define	RTC_IMSC	0x10	/* Interrupt mask and set register */
 33#define	RTC_RIS		0x14	/* Raw interrupt status register */
 34#define	RTC_MIS		0x18	/* Masked interrupt status register */
 35#define	RTC_ICR		0x1c	/* Interrupt clear register */
 36/* ST variants have additional timer functionality */
 37#define RTC_TDR		0x20	/* Timer data read register */
 38#define RTC_TLR		0x24	/* Timer data load register */
 39#define RTC_TCR		0x28	/* Timer control register */
 40#define RTC_YDR		0x30	/* Year data read register */
 41#define RTC_YMR		0x34	/* Year match register */
 42#define RTC_YLR		0x38	/* Year data load register */
 43
 44#define RTC_CR_EN	(1 << 0)	/* counter enable bit */
 45#define RTC_CR_CWEN	(1 << 26)	/* Clockwatch enable bit */
 46
 47#define RTC_TCR_EN	(1 << 1) /* Periodic timer enable bit */
 48
 49/* Common bit definitions for Interrupt status and control registers */
 50#define RTC_BIT_AI	(1 << 0) /* Alarm interrupt bit */
 51#define RTC_BIT_PI	(1 << 1) /* Periodic interrupt bit. ST variants only. */
 52
 53/* Common bit definations for ST v2 for reading/writing time */
 54#define RTC_SEC_SHIFT 0
 55#define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
 56#define RTC_MIN_SHIFT 6
 57#define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
 58#define RTC_HOUR_SHIFT 12
 59#define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
 60#define RTC_WDAY_SHIFT 17
 61#define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
 62#define RTC_MDAY_SHIFT 20
 63#define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
 64#define RTC_MON_SHIFT 25
 65#define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
 66
 67#define RTC_TIMER_FREQ 32768
 68
 69/**
 70 * struct pl031_vendor_data - per-vendor variations
 71 * @ops: the vendor-specific operations used on this silicon version
 72 * @clockwatch: if this is an ST Microelectronics silicon version with a
 73 *	clockwatch function
 74 * @st_weekday: if this is an ST Microelectronics silicon version that need
 75 *	the weekday fix
 76 * @irqflags: special IRQ flags per variant
 77 * @range_min: minimum date/time supported by the RTC
 78 * @range_max: maximum date/time supported by the RTC
 79 */
 80struct pl031_vendor_data {
 81	struct rtc_class_ops ops;
 82	bool clockwatch;
 83	bool st_weekday;
 84	unsigned long irqflags;
 85	time64_t range_min;
 86	timeu64_t range_max;
 87};
 88
 89struct pl031_local {
 90	struct pl031_vendor_data *vendor;
 91	struct rtc_device *rtc;
 92	void __iomem *base;
 93};
 94
 95static int pl031_alarm_irq_enable(struct device *dev,
 96	unsigned int enabled)
 97{
 98	struct pl031_local *ldata = dev_get_drvdata(dev);
 99	unsigned long imsc;
100
101	/* Clear any pending alarm interrupts. */
102	writel(RTC_BIT_AI, ldata->base + RTC_ICR);
103
104	imsc = readl(ldata->base + RTC_IMSC);
105
106	if (enabled == 1)
107		writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
108	else
109		writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
110
111	return 0;
112}
113
114/*
115 * Convert Gregorian date to ST v2 RTC format.
116 */
117static int pl031_stv2_tm_to_time(struct device *dev,
118				 struct rtc_time *tm, unsigned long *st_time,
119	unsigned long *bcd_year)
120{
121	int year = tm->tm_year + 1900;
122	int wday = tm->tm_wday;
123
124	/* wday masking is not working in hardware so wday must be valid */
125	if (wday < -1 || wday > 6) {
126		dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
127		return -EINVAL;
128	} else if (wday == -1) {
129		/* wday is not provided, calculate it here */
130		struct rtc_time calc_tm;
131
132		rtc_time64_to_tm(rtc_tm_to_time64(tm), &calc_tm);
133		wday = calc_tm.tm_wday;
134	}
135
136	*bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
137
138	*st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
139			|	(tm->tm_mday << RTC_MDAY_SHIFT)
140			|	((wday + 1) << RTC_WDAY_SHIFT)
141			|	(tm->tm_hour << RTC_HOUR_SHIFT)
142			|	(tm->tm_min << RTC_MIN_SHIFT)
143			|	(tm->tm_sec << RTC_SEC_SHIFT);
144
145	return 0;
146}
147
148/*
149 * Convert ST v2 RTC format to Gregorian date.
150 */
151static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
152	struct rtc_time *tm)
153{
154	tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
155	tm->tm_mon  = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
156	tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
157	tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
158	tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
159	tm->tm_min  = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
160	tm->tm_sec  = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
161
162	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
163	tm->tm_year -= 1900;
164
165	return 0;
166}
167
168static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
169{
170	struct pl031_local *ldata = dev_get_drvdata(dev);
171
172	pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
173			readl(ldata->base + RTC_YDR), tm);
174
175	return 0;
176}
177
178static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
179{
180	unsigned long time;
181	unsigned long bcd_year;
182	struct pl031_local *ldata = dev_get_drvdata(dev);
183	int ret;
184
185	ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
186	if (ret == 0) {
187		writel(bcd_year, ldata->base + RTC_YLR);
188		writel(time, ldata->base + RTC_LR);
189	}
190
191	return ret;
192}
193
194static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
195{
196	struct pl031_local *ldata = dev_get_drvdata(dev);
197	int ret;
198
199	ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
200			readl(ldata->base + RTC_YMR), &alarm->time);
201
202	alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
203	alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
204
205	return ret;
206}
207
208static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
209{
210	struct pl031_local *ldata = dev_get_drvdata(dev);
211	unsigned long time;
212	unsigned long bcd_year;
213	int ret;
214
215	ret = pl031_stv2_tm_to_time(dev, &alarm->time,
216				    &time, &bcd_year);
217	if (ret == 0) {
218		writel(bcd_year, ldata->base + RTC_YMR);
219		writel(time, ldata->base + RTC_MR);
220
221		pl031_alarm_irq_enable(dev, alarm->enabled);
222	}
223
224	return ret;
225}
226
227static irqreturn_t pl031_interrupt(int irq, void *dev_id)
228{
229	struct pl031_local *ldata = dev_id;
230	unsigned long rtcmis;
231	unsigned long events = 0;
232
233	rtcmis = readl(ldata->base + RTC_MIS);
234	if (rtcmis & RTC_BIT_AI) {
235		writel(RTC_BIT_AI, ldata->base + RTC_ICR);
236		events |= (RTC_AF | RTC_IRQF);
237		rtc_update_irq(ldata->rtc, 1, events);
238
239		return IRQ_HANDLED;
240	}
241
242	return IRQ_NONE;
243}
244
245static int pl031_read_time(struct device *dev, struct rtc_time *tm)
246{
247	struct pl031_local *ldata = dev_get_drvdata(dev);
248
249	rtc_time64_to_tm(readl(ldata->base + RTC_DR), tm);
250
251	return 0;
252}
253
254static int pl031_set_time(struct device *dev, struct rtc_time *tm)
255{
256	struct pl031_local *ldata = dev_get_drvdata(dev);
257
258	writel(rtc_tm_to_time64(tm), ldata->base + RTC_LR);
259
260	return 0;
261}
262
263static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
264{
265	struct pl031_local *ldata = dev_get_drvdata(dev);
266
267	rtc_time64_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
268
269	alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
270	alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
271
272	return 0;
273}
274
275static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
276{
277	struct pl031_local *ldata = dev_get_drvdata(dev);
278
279	writel(rtc_tm_to_time64(&alarm->time), ldata->base + RTC_MR);
280	pl031_alarm_irq_enable(dev, alarm->enabled);
281
282	return 0;
283}
284
285static void pl031_remove(struct amba_device *adev)
286{
287	struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
288
289	if (adev->irq[0])
290		free_irq(adev->irq[0], ldata);
291	amba_release_regions(adev);
292}
293
294static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
295{
296	int ret;
297	struct pl031_local *ldata;
298	struct pl031_vendor_data *vendor = id->data;
299	struct rtc_class_ops *ops;
300	unsigned long time, data;
301
302	ret = amba_request_regions(adev, NULL);
303	if (ret)
304		goto err_req;
305
306	ldata = devm_kzalloc(&adev->dev, sizeof(struct pl031_local),
307			     GFP_KERNEL);
308	ops = devm_kmemdup(&adev->dev, &vendor->ops, sizeof(vendor->ops),
309			   GFP_KERNEL);
310	if (!ldata || !ops) {
311		ret = -ENOMEM;
312		goto out;
313	}
314
315	ldata->vendor = vendor;
316	ldata->base = devm_ioremap(&adev->dev, adev->res.start,
317				   resource_size(&adev->res));
318	if (!ldata->base) {
319		ret = -ENOMEM;
320		goto out;
321	}
322
323	amba_set_drvdata(adev, ldata);
324
325	dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev));
326	dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev));
327
328	data = readl(ldata->base + RTC_CR);
329	/* Enable the clockwatch on ST Variants */
330	if (vendor->clockwatch)
331		data |= RTC_CR_CWEN;
332	else
333		data |= RTC_CR_EN;
334	writel(data, ldata->base + RTC_CR);
335
336	/*
337	 * On ST PL031 variants, the RTC reset value does not provide correct
338	 * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
339	 */
340	if (vendor->st_weekday) {
341		if (readl(ldata->base + RTC_YDR) == 0x2000) {
342			time = readl(ldata->base + RTC_DR);
343			if ((time &
344			     (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
345			    == 0x02120000) {
346				time = time | (0x7 << RTC_WDAY_SHIFT);
347				writel(0x2000, ldata->base + RTC_YLR);
348				writel(time, ldata->base + RTC_LR);
349			}
350		}
351	}
352
353	devm_device_init_wakeup(&adev->dev);
354	ldata->rtc = devm_rtc_allocate_device(&adev->dev);
355	if (IS_ERR(ldata->rtc)) {
356		ret = PTR_ERR(ldata->rtc);
357		goto out;
358	}
359
360	if (!adev->irq[0])
361		clear_bit(RTC_FEATURE_ALARM, ldata->rtc->features);
362
363	ldata->rtc->ops = ops;
364	ldata->rtc->range_min = vendor->range_min;
365	ldata->rtc->range_max = vendor->range_max;
366
367	ret = devm_rtc_register_device(ldata->rtc);
368	if (ret)
369		goto out;
370
371	if (adev->irq[0]) {
372		ret = request_irq(adev->irq[0], pl031_interrupt,
373				  vendor->irqflags, "rtc-pl031", ldata);
374		if (ret)
375			goto out;
376		devm_pm_set_wake_irq(&adev->dev, adev->irq[0]);
377	}
378	return 0;
379
380out:
381	amba_release_regions(adev);
382err_req:
383
384	return ret;
385}
386
387/* Operations for the original ARM version */
388static struct pl031_vendor_data arm_pl031 = {
389	.ops = {
390		.read_time = pl031_read_time,
391		.set_time = pl031_set_time,
392		.read_alarm = pl031_read_alarm,
393		.set_alarm = pl031_set_alarm,
394		.alarm_irq_enable = pl031_alarm_irq_enable,
395	},
396	.range_max = U32_MAX,
397};
398
399/* The First ST derivative */
400static struct pl031_vendor_data stv1_pl031 = {
401	.ops = {
402		.read_time = pl031_read_time,
403		.set_time = pl031_set_time,
404		.read_alarm = pl031_read_alarm,
405		.set_alarm = pl031_set_alarm,
406		.alarm_irq_enable = pl031_alarm_irq_enable,
407	},
408	.clockwatch = true,
409	.st_weekday = true,
410	.range_max = U32_MAX,
411};
412
413/* And the second ST derivative */
414static struct pl031_vendor_data stv2_pl031 = {
415	.ops = {
416		.read_time = pl031_stv2_read_time,
417		.set_time = pl031_stv2_set_time,
418		.read_alarm = pl031_stv2_read_alarm,
419		.set_alarm = pl031_stv2_set_alarm,
420		.alarm_irq_enable = pl031_alarm_irq_enable,
421	},
422	.clockwatch = true,
423	.st_weekday = true,
424	/*
425	 * This variant shares the IRQ with another block and must not
426	 * suspend that IRQ line.
427	 * TODO check if it shares with IRQF_NO_SUSPEND user, else we can
428	 * remove IRQF_COND_SUSPEND
429	 */
430	.irqflags = IRQF_SHARED | IRQF_COND_SUSPEND,
431	.range_min = RTC_TIMESTAMP_BEGIN_0000,
432	.range_max = RTC_TIMESTAMP_END_9999,
433};
434
435static const struct amba_id pl031_ids[] = {
436	{
437		.id = 0x00041031,
438		.mask = 0x000fffff,
439		.data = &arm_pl031,
440	},
441	/* ST Micro variants */
442	{
443		.id = 0x00180031,
444		.mask = 0x00ffffff,
445		.data = &stv1_pl031,
446	},
447	{
448		.id = 0x00280031,
449		.mask = 0x00ffffff,
450		.data = &stv2_pl031,
451	},
452	{0, 0},
453};
454
455MODULE_DEVICE_TABLE(amba, pl031_ids);
456
457static struct amba_driver pl031_driver = {
458	.drv = {
459		.name = "rtc-pl031",
460	},
461	.id_table = pl031_ids,
462	.probe = pl031_probe,
463	.remove = pl031_remove,
464};
465
466module_amba_driver(pl031_driver);
467
468MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
469MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
470MODULE_LICENSE("GPL");