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  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * DaVinci Power Management and Real Time Clock Driver for TI platforms
  4 *
  5 * Copyright (C) 2009 Texas Instruments, Inc
  6 *
  7 * Author: Miguel Aguilar <miguel.aguilar@ridgerun.com>
  8 */
  9#include <linux/kernel.h>
 10#include <linux/init.h>
 11#include <linux/module.h>
 12#include <linux/ioport.h>
 13#include <linux/delay.h>
 14#include <linux/spinlock.h>
 15#include <linux/rtc.h>
 16#include <linux/bcd.h>
 17#include <linux/platform_device.h>
 18#include <linux/io.h>
 19#include <linux/slab.h>
 20
 21/*
 22 * The DaVinci RTC is a simple RTC with the following
 23 * Sec: 0 - 59 : BCD count
 24 * Min: 0 - 59 : BCD count
 25 * Hour: 0 - 23 : BCD count
 26 * Day: 0 - 0x7FFF(32767) : Binary count ( Over 89 years )
 27 */
 28
 29/* PRTC interface registers */
 30#define DAVINCI_PRTCIF_PID		0x00
 31#define PRTCIF_CTLR			0x04
 32#define PRTCIF_LDATA			0x08
 33#define PRTCIF_UDATA			0x0C
 34#define PRTCIF_INTEN			0x10
 35#define PRTCIF_INTFLG			0x14
 36
 37/* PRTCIF_CTLR bit fields */
 38#define PRTCIF_CTLR_BUSY		BIT(31)
 39#define PRTCIF_CTLR_SIZE		BIT(25)
 40#define PRTCIF_CTLR_DIR			BIT(24)
 41#define PRTCIF_CTLR_BENU_MSB		BIT(23)
 42#define PRTCIF_CTLR_BENU_3RD_BYTE	BIT(22)
 43#define PRTCIF_CTLR_BENU_2ND_BYTE	BIT(21)
 44#define PRTCIF_CTLR_BENU_LSB		BIT(20)
 45#define PRTCIF_CTLR_BENU_MASK		(0x00F00000)
 46#define PRTCIF_CTLR_BENL_MSB		BIT(19)
 47#define PRTCIF_CTLR_BENL_3RD_BYTE	BIT(18)
 48#define PRTCIF_CTLR_BENL_2ND_BYTE	BIT(17)
 49#define PRTCIF_CTLR_BENL_LSB		BIT(16)
 50#define PRTCIF_CTLR_BENL_MASK		(0x000F0000)
 51
 52/* PRTCIF_INTEN bit fields */
 53#define PRTCIF_INTEN_RTCSS		BIT(1)
 54#define PRTCIF_INTEN_RTCIF		BIT(0)
 55#define PRTCIF_INTEN_MASK		(PRTCIF_INTEN_RTCSS \
 56					| PRTCIF_INTEN_RTCIF)
 57
 58/* PRTCIF_INTFLG bit fields */
 59#define PRTCIF_INTFLG_RTCSS		BIT(1)
 60#define PRTCIF_INTFLG_RTCIF		BIT(0)
 61#define PRTCIF_INTFLG_MASK		(PRTCIF_INTFLG_RTCSS \
 62					| PRTCIF_INTFLG_RTCIF)
 63
 64/* PRTC subsystem registers */
 65#define PRTCSS_RTC_INTC_EXTENA1		(0x0C)
 66#define PRTCSS_RTC_CTRL			(0x10)
 67#define PRTCSS_RTC_WDT			(0x11)
 68#define PRTCSS_RTC_TMR0			(0x12)
 69#define PRTCSS_RTC_TMR1			(0x13)
 70#define PRTCSS_RTC_CCTRL		(0x14)
 71#define PRTCSS_RTC_SEC			(0x15)
 72#define PRTCSS_RTC_MIN			(0x16)
 73#define PRTCSS_RTC_HOUR			(0x17)
 74#define PRTCSS_RTC_DAY0			(0x18)
 75#define PRTCSS_RTC_DAY1			(0x19)
 76#define PRTCSS_RTC_AMIN			(0x1A)
 77#define PRTCSS_RTC_AHOUR		(0x1B)
 78#define PRTCSS_RTC_ADAY0		(0x1C)
 79#define PRTCSS_RTC_ADAY1		(0x1D)
 80#define PRTCSS_RTC_CLKC_CNT		(0x20)
 81
 82/* PRTCSS_RTC_INTC_EXTENA1 */
 83#define PRTCSS_RTC_INTC_EXTENA1_MASK	(0x07)
 84
 85/* PRTCSS_RTC_CTRL bit fields */
 86#define PRTCSS_RTC_CTRL_WDTBUS		BIT(7)
 87#define PRTCSS_RTC_CTRL_WEN		BIT(6)
 88#define PRTCSS_RTC_CTRL_WDRT		BIT(5)
 89#define PRTCSS_RTC_CTRL_WDTFLG		BIT(4)
 90#define PRTCSS_RTC_CTRL_TE		BIT(3)
 91#define PRTCSS_RTC_CTRL_TIEN		BIT(2)
 92#define PRTCSS_RTC_CTRL_TMRFLG		BIT(1)
 93#define PRTCSS_RTC_CTRL_TMMD		BIT(0)
 94
 95/* PRTCSS_RTC_CCTRL bit fields */
 96#define PRTCSS_RTC_CCTRL_CALBUSY	BIT(7)
 97#define PRTCSS_RTC_CCTRL_DAEN		BIT(5)
 98#define PRTCSS_RTC_CCTRL_HAEN		BIT(4)
 99#define PRTCSS_RTC_CCTRL_MAEN		BIT(3)
100#define PRTCSS_RTC_CCTRL_ALMFLG		BIT(2)
101#define PRTCSS_RTC_CCTRL_AIEN		BIT(1)
102#define PRTCSS_RTC_CCTRL_CAEN		BIT(0)
103
104static DEFINE_SPINLOCK(davinci_rtc_lock);
105
106struct davinci_rtc {
107	struct rtc_device		*rtc;
108	void __iomem			*base;
109	int				irq;
110};
111
112static inline void rtcif_write(struct davinci_rtc *davinci_rtc,
113			       u32 val, u32 addr)
114{
115	writel(val, davinci_rtc->base + addr);
116}
117
118static inline u32 rtcif_read(struct davinci_rtc *davinci_rtc, u32 addr)
119{
120	return readl(davinci_rtc->base + addr);
121}
122
123static inline void rtcif_wait(struct davinci_rtc *davinci_rtc)
124{
125	while (rtcif_read(davinci_rtc, PRTCIF_CTLR) & PRTCIF_CTLR_BUSY)
126		cpu_relax();
127}
128
129static inline void rtcss_write(struct davinci_rtc *davinci_rtc,
130			       unsigned long val, u8 addr)
131{
132	rtcif_wait(davinci_rtc);
133
134	rtcif_write(davinci_rtc, PRTCIF_CTLR_BENL_LSB | addr, PRTCIF_CTLR);
135	rtcif_write(davinci_rtc, val, PRTCIF_LDATA);
136
137	rtcif_wait(davinci_rtc);
138}
139
140static inline u8 rtcss_read(struct davinci_rtc *davinci_rtc, u8 addr)
141{
142	rtcif_wait(davinci_rtc);
143
144	rtcif_write(davinci_rtc, PRTCIF_CTLR_DIR | PRTCIF_CTLR_BENL_LSB | addr,
145		    PRTCIF_CTLR);
146
147	rtcif_wait(davinci_rtc);
148
149	return rtcif_read(davinci_rtc, PRTCIF_LDATA);
150}
151
152static inline void davinci_rtcss_calendar_wait(struct davinci_rtc *davinci_rtc)
153{
154	while (rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL) &
155	       PRTCSS_RTC_CCTRL_CALBUSY)
156		cpu_relax();
157}
158
159static irqreturn_t davinci_rtc_interrupt(int irq, void *class_dev)
160{
161	struct davinci_rtc *davinci_rtc = class_dev;
162	unsigned long events = 0;
163	u32 irq_flg;
164	u8 alm_irq, tmr_irq;
165	u8 rtc_ctrl, rtc_cctrl;
166	int ret = IRQ_NONE;
167
168	irq_flg = rtcif_read(davinci_rtc, PRTCIF_INTFLG) &
169		  PRTCIF_INTFLG_RTCSS;
170
171	alm_irq = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL) &
172		  PRTCSS_RTC_CCTRL_ALMFLG;
173
174	tmr_irq = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL) &
175		  PRTCSS_RTC_CTRL_TMRFLG;
176
177	if (irq_flg) {
178		if (alm_irq) {
179			events |= RTC_IRQF | RTC_AF;
180			rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);
181			rtc_cctrl |=  PRTCSS_RTC_CCTRL_ALMFLG;
182			rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);
183		} else if (tmr_irq) {
184			events |= RTC_IRQF | RTC_PF;
185			rtc_ctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL);
186			rtc_ctrl |=  PRTCSS_RTC_CTRL_TMRFLG;
187			rtcss_write(davinci_rtc, rtc_ctrl, PRTCSS_RTC_CTRL);
188		}
189
190		rtcif_write(davinci_rtc, PRTCIF_INTFLG_RTCSS,
191				    PRTCIF_INTFLG);
192		rtc_update_irq(davinci_rtc->rtc, 1, events);
193
194		ret = IRQ_HANDLED;
195	}
196
197	return ret;
198}
199
200static int
201davinci_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
202{
203	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
204	u8 rtc_ctrl;
205	unsigned long flags;
206	int ret = 0;
207
208	spin_lock_irqsave(&davinci_rtc_lock, flags);
209
210	rtc_ctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL);
211
212	switch (cmd) {
213	case RTC_WIE_ON:
214		rtc_ctrl |= PRTCSS_RTC_CTRL_WEN | PRTCSS_RTC_CTRL_WDTFLG;
215		break;
216	case RTC_WIE_OFF:
217		rtc_ctrl &= ~PRTCSS_RTC_CTRL_WEN;
218		break;
219	default:
220		ret = -ENOIOCTLCMD;
221	}
222
223	rtcss_write(davinci_rtc, rtc_ctrl, PRTCSS_RTC_CTRL);
224
225	spin_unlock_irqrestore(&davinci_rtc_lock, flags);
226
227	return ret;
228}
229
230static void convertfromdays(u16 days, struct rtc_time *tm)
231{
232	int tmp_days, year, mon;
233
234	for (year = 2000;; year++) {
235		tmp_days = rtc_year_days(1, 12, year);
236		if (days >= tmp_days)
237			days -= tmp_days;
238		else {
239			for (mon = 0;; mon++) {
240				tmp_days = rtc_month_days(mon, year);
241				if (days >= tmp_days) {
242					days -= tmp_days;
243				} else {
244					tm->tm_year = year - 1900;
245					tm->tm_mon = mon;
246					tm->tm_mday = days + 1;
247					break;
248				}
249			}
250			break;
251		}
252	}
253}
254
255static void convert2days(u16 *days, struct rtc_time *tm)
256{
257	int i;
258	*days = 0;
259
260	for (i = 2000; i < 1900 + tm->tm_year; i++)
261		*days += rtc_year_days(1, 12, i);
262
263	*days += rtc_year_days(tm->tm_mday, tm->tm_mon, 1900 + tm->tm_year);
264}
265
266static int davinci_rtc_read_time(struct device *dev, struct rtc_time *tm)
267{
268	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
269	u16 days = 0;
270	u8 day0, day1;
271	unsigned long flags;
272
273	spin_lock_irqsave(&davinci_rtc_lock, flags);
274
275	davinci_rtcss_calendar_wait(davinci_rtc);
276	tm->tm_sec = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_SEC));
277
278	davinci_rtcss_calendar_wait(davinci_rtc);
279	tm->tm_min = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_MIN));
280
281	davinci_rtcss_calendar_wait(davinci_rtc);
282	tm->tm_hour = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_HOUR));
283
284	davinci_rtcss_calendar_wait(davinci_rtc);
285	day0 = rtcss_read(davinci_rtc, PRTCSS_RTC_DAY0);
286
287	davinci_rtcss_calendar_wait(davinci_rtc);
288	day1 = rtcss_read(davinci_rtc, PRTCSS_RTC_DAY1);
289
290	spin_unlock_irqrestore(&davinci_rtc_lock, flags);
291
292	days |= day1;
293	days <<= 8;
294	days |= day0;
295
296	convertfromdays(days, tm);
297
298	return 0;
299}
300
301static int davinci_rtc_set_time(struct device *dev, struct rtc_time *tm)
302{
303	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
304	u16 days;
305	u8 rtc_cctrl;
306	unsigned long flags;
307
308	convert2days(&days, tm);
309
310	spin_lock_irqsave(&davinci_rtc_lock, flags);
311
312	davinci_rtcss_calendar_wait(davinci_rtc);
313	rtcss_write(davinci_rtc, bin2bcd(tm->tm_sec), PRTCSS_RTC_SEC);
314
315	davinci_rtcss_calendar_wait(davinci_rtc);
316	rtcss_write(davinci_rtc, bin2bcd(tm->tm_min), PRTCSS_RTC_MIN);
317
318	davinci_rtcss_calendar_wait(davinci_rtc);
319	rtcss_write(davinci_rtc, bin2bcd(tm->tm_hour), PRTCSS_RTC_HOUR);
320
321	davinci_rtcss_calendar_wait(davinci_rtc);
322	rtcss_write(davinci_rtc, days & 0xFF, PRTCSS_RTC_DAY0);
323
324	davinci_rtcss_calendar_wait(davinci_rtc);
325	rtcss_write(davinci_rtc, (days & 0xFF00) >> 8, PRTCSS_RTC_DAY1);
326
327	rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);
328	rtc_cctrl |= PRTCSS_RTC_CCTRL_CAEN;
329	rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);
330
331	spin_unlock_irqrestore(&davinci_rtc_lock, flags);
332
333	return 0;
334}
335
336static int davinci_rtc_alarm_irq_enable(struct device *dev,
337					unsigned int enabled)
338{
339	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
340	unsigned long flags;
341	u8 rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);
342
343	spin_lock_irqsave(&davinci_rtc_lock, flags);
344
345	if (enabled)
346		rtc_cctrl |= PRTCSS_RTC_CCTRL_DAEN |
347			     PRTCSS_RTC_CCTRL_HAEN |
348			     PRTCSS_RTC_CCTRL_MAEN |
349			     PRTCSS_RTC_CCTRL_ALMFLG |
350			     PRTCSS_RTC_CCTRL_AIEN;
351	else
352		rtc_cctrl &= ~PRTCSS_RTC_CCTRL_AIEN;
353
354	davinci_rtcss_calendar_wait(davinci_rtc);
355	rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);
356
357	spin_unlock_irqrestore(&davinci_rtc_lock, flags);
358
359	return 0;
360}
361
362static int davinci_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
363{
364	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
365	u16 days = 0;
366	u8 day0, day1;
367	unsigned long flags;
368
369	alm->time.tm_sec = 0;
370
371	spin_lock_irqsave(&davinci_rtc_lock, flags);
372
373	davinci_rtcss_calendar_wait(davinci_rtc);
374	alm->time.tm_min = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_AMIN));
375
376	davinci_rtcss_calendar_wait(davinci_rtc);
377	alm->time.tm_hour = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_AHOUR));
378
379	davinci_rtcss_calendar_wait(davinci_rtc);
380	day0 = rtcss_read(davinci_rtc, PRTCSS_RTC_ADAY0);
381
382	davinci_rtcss_calendar_wait(davinci_rtc);
383	day1 = rtcss_read(davinci_rtc, PRTCSS_RTC_ADAY1);
384
385	spin_unlock_irqrestore(&davinci_rtc_lock, flags);
386	days |= day1;
387	days <<= 8;
388	days |= day0;
389
390	convertfromdays(days, &alm->time);
391
392	alm->pending = !!(rtcss_read(davinci_rtc,
393			  PRTCSS_RTC_CCTRL) &
394			PRTCSS_RTC_CCTRL_AIEN);
395	alm->enabled = alm->pending && device_may_wakeup(dev);
396
397	return 0;
398}
399
400static int davinci_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
401{
402	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
403	unsigned long flags;
404	u16 days;
405
406	convert2days(&days, &alm->time);
407
408	spin_lock_irqsave(&davinci_rtc_lock, flags);
409
410	davinci_rtcss_calendar_wait(davinci_rtc);
411	rtcss_write(davinci_rtc, bin2bcd(alm->time.tm_min), PRTCSS_RTC_AMIN);
412
413	davinci_rtcss_calendar_wait(davinci_rtc);
414	rtcss_write(davinci_rtc, bin2bcd(alm->time.tm_hour), PRTCSS_RTC_AHOUR);
415
416	davinci_rtcss_calendar_wait(davinci_rtc);
417	rtcss_write(davinci_rtc, days & 0xFF, PRTCSS_RTC_ADAY0);
418
419	davinci_rtcss_calendar_wait(davinci_rtc);
420	rtcss_write(davinci_rtc, (days & 0xFF00) >> 8, PRTCSS_RTC_ADAY1);
421
422	spin_unlock_irqrestore(&davinci_rtc_lock, flags);
423
424	return 0;
425}
426
427static const struct rtc_class_ops davinci_rtc_ops = {
428	.ioctl			= davinci_rtc_ioctl,
429	.read_time		= davinci_rtc_read_time,
430	.set_time		= davinci_rtc_set_time,
431	.alarm_irq_enable	= davinci_rtc_alarm_irq_enable,
432	.read_alarm		= davinci_rtc_read_alarm,
433	.set_alarm		= davinci_rtc_set_alarm,
434};
435
436static int __init davinci_rtc_probe(struct platform_device *pdev)
437{
438	struct device *dev = &pdev->dev;
439	struct davinci_rtc *davinci_rtc;
440	int ret = 0;
441
442	davinci_rtc = devm_kzalloc(&pdev->dev, sizeof(struct davinci_rtc), GFP_KERNEL);
443	if (!davinci_rtc)
444		return -ENOMEM;
445
446	davinci_rtc->irq = platform_get_irq(pdev, 0);
447	if (davinci_rtc->irq < 0)
448		return davinci_rtc->irq;
449
450	davinci_rtc->base = devm_platform_ioremap_resource(pdev, 0);
451	if (IS_ERR(davinci_rtc->base))
452		return PTR_ERR(davinci_rtc->base);
453
454	platform_set_drvdata(pdev, davinci_rtc);
455
456	davinci_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
457	if (IS_ERR(davinci_rtc->rtc))
458		return PTR_ERR(davinci_rtc->rtc);
459
460	davinci_rtc->rtc->ops = &davinci_rtc_ops;
461	davinci_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
462	davinci_rtc->rtc->range_max = RTC_TIMESTAMP_BEGIN_2000 + (1 << 16) * 86400ULL - 1;
463
464	rtcif_write(davinci_rtc, PRTCIF_INTFLG_RTCSS, PRTCIF_INTFLG);
465	rtcif_write(davinci_rtc, 0, PRTCIF_INTEN);
466	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_INTC_EXTENA1);
467
468	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_CTRL);
469	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_CCTRL);
470
471	ret = devm_request_irq(dev, davinci_rtc->irq, davinci_rtc_interrupt,
472			  0, "davinci_rtc", davinci_rtc);
473	if (ret < 0) {
474		dev_err(dev, "unable to register davinci RTC interrupt\n");
475		return ret;
476	}
477
478	/* Enable interrupts */
479	rtcif_write(davinci_rtc, PRTCIF_INTEN_RTCSS, PRTCIF_INTEN);
480	rtcss_write(davinci_rtc, PRTCSS_RTC_INTC_EXTENA1_MASK,
481			    PRTCSS_RTC_INTC_EXTENA1);
482
483	rtcss_write(davinci_rtc, PRTCSS_RTC_CCTRL_CAEN, PRTCSS_RTC_CCTRL);
484
485	device_init_wakeup(&pdev->dev, 0);
486
487	return rtc_register_device(davinci_rtc->rtc);
488}
489
490static int __exit davinci_rtc_remove(struct platform_device *pdev)
491{
492	struct davinci_rtc *davinci_rtc = platform_get_drvdata(pdev);
493
494	device_init_wakeup(&pdev->dev, 0);
495
496	rtcif_write(davinci_rtc, 0, PRTCIF_INTEN);
497
498	return 0;
499}
500
501static struct platform_driver davinci_rtc_driver = {
502	.remove		= __exit_p(davinci_rtc_remove),
503	.driver		= {
504		.name = "rtc_davinci",
505	},
506};
507
508module_platform_driver_probe(davinci_rtc_driver, davinci_rtc_probe);
509
510MODULE_AUTHOR("Miguel Aguilar <miguel.aguilar@ridgerun.com>");
511MODULE_DESCRIPTION("Texas Instruments DaVinci PRTC Driver");
512MODULE_LICENSE("GPL");