drivers/rtc/rtc-davinci.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * DaVinci Power Management and Real Time Clock Driver for TI platforms
  *
  * Copyright (C) 2009 Texas Instruments, Inc
  *
  * Author: Miguel Aguilar <miguel.aguilar@ridgerun.com>
  */
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/ioport.h>
 #include <linux/delay.h>
 #include <linux/spinlock.h>
 #include <linux/rtc.h>
 #include <linux/bcd.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/slab.h>

 /*
  * The DaVinci RTC is a simple RTC with the following
  * Sec: 0 - 59 : BCD count
  * Min: 0 - 59 : BCD count
  * Hour: 0 - 23 : BCD count
  * Day: 0 - 0x7FFF(32767) : Binary count ( Over 89 years )
  */

 /* PRTC interface registers */
 #define DAVINCI_PRTCIF_PID		0x00
 #define PRTCIF_CTLR			0x04
 #define PRTCIF_LDATA			0x08
 #define PRTCIF_UDATA			0x0C
 #define PRTCIF_INTEN			0x10
 #define PRTCIF_INTFLG			0x14

 /* PRTCIF_CTLR bit fields */
 #define PRTCIF_CTLR_BUSY		BIT(31)
 #define PRTCIF_CTLR_SIZE		BIT(25)
 #define PRTCIF_CTLR_DIR			BIT(24)
 #define PRTCIF_CTLR_BENU_MSB		BIT(23)
 #define PRTCIF_CTLR_BENU_3RD_BYTE	BIT(22)
 #define PRTCIF_CTLR_BENU_2ND_BYTE	BIT(21)
 #define PRTCIF_CTLR_BENU_LSB		BIT(20)
 #define PRTCIF_CTLR_BENU_MASK		(0x00F00000)
 #define PRTCIF_CTLR_BENL_MSB		BIT(19)
 #define PRTCIF_CTLR_BENL_3RD_BYTE	BIT(18)
 #define PRTCIF_CTLR_BENL_2ND_BYTE	BIT(17)
 #define PRTCIF_CTLR_BENL_LSB		BIT(16)
 #define PRTCIF_CTLR_BENL_MASK		(0x000F0000)

 /* PRTCIF_INTEN bit fields */
 #define PRTCIF_INTEN_RTCSS		BIT(1)
 #define PRTCIF_INTEN_RTCIF		BIT(0)
 #define PRTCIF_INTEN_MASK		(PRTCIF_INTEN_RTCSS \
 					| PRTCIF_INTEN_RTCIF)

 /* PRTCIF_INTFLG bit fields */
 #define PRTCIF_INTFLG_RTCSS		BIT(1)
 #define PRTCIF_INTFLG_RTCIF		BIT(0)
 #define PRTCIF_INTFLG_MASK		(PRTCIF_INTFLG_RTCSS \
 					| PRTCIF_INTFLG_RTCIF)

 /* PRTC subsystem registers */
 #define PRTCSS_RTC_INTC_EXTENA1		(0x0C)
 #define PRTCSS_RTC_CTRL			(0x10)
 #define PRTCSS_RTC_WDT			(0x11)
 #define PRTCSS_RTC_TMR0			(0x12)
 #define PRTCSS_RTC_TMR1			(0x13)
 #define PRTCSS_RTC_CCTRL		(0x14)
 #define PRTCSS_RTC_SEC			(0x15)
 #define PRTCSS_RTC_MIN			(0x16)
 #define PRTCSS_RTC_HOUR			(0x17)
 #define PRTCSS_RTC_DAY0			(0x18)
 #define PRTCSS_RTC_DAY1			(0x19)
 #define PRTCSS_RTC_AMIN			(0x1A)
 #define PRTCSS_RTC_AHOUR		(0x1B)
 #define PRTCSS_RTC_ADAY0		(0x1C)
 #define PRTCSS_RTC_ADAY1		(0x1D)
 #define PRTCSS_RTC_CLKC_CNT		(0x20)

 /* PRTCSS_RTC_INTC_EXTENA1 */
 #define PRTCSS_RTC_INTC_EXTENA1_MASK	(0x07)

 /* PRTCSS_RTC_CTRL bit fields */
 #define PRTCSS_RTC_CTRL_WDTBUS		BIT(7)
 #define PRTCSS_RTC_CTRL_WEN		BIT(6)
 #define PRTCSS_RTC_CTRL_WDRT		BIT(5)
 #define PRTCSS_RTC_CTRL_WDTFLG		BIT(4)
 #define PRTCSS_RTC_CTRL_TE		BIT(3)
 #define PRTCSS_RTC_CTRL_TIEN		BIT(2)
 #define PRTCSS_RTC_CTRL_TMRFLG		BIT(1)
 #define PRTCSS_RTC_CTRL_TMMD		BIT(0)

 /* PRTCSS_RTC_CCTRL bit fields */
 #define PRTCSS_RTC_CCTRL_CALBUSY	BIT(7)
 #define PRTCSS_RTC_CCTRL_DAEN		BIT(5)
 #define PRTCSS_RTC_CCTRL_HAEN		BIT(4)
 #define PRTCSS_RTC_CCTRL_MAEN		BIT(3)
 #define PRTCSS_RTC_CCTRL_ALMFLG		BIT(2)
 #define PRTCSS_RTC_CCTRL_AIEN		BIT(1)
 #define PRTCSS_RTC_CCTRL_CAEN		BIT(0)

 static DEFINE_SPINLOCK(davinci_rtc_lock);

 struct davinci_rtc {
 	struct rtc_device		*rtc;
 	void __iomem			*base;
 	int				irq;
 };

 static inline void rtcif_write(struct davinci_rtc *davinci_rtc,
 			       u32 val, u32 addr)
 {
 	writel(val, davinci_rtc->base + addr);
 }

 static inline u32 rtcif_read(struct davinci_rtc *davinci_rtc, u32 addr)
 {
 	return readl(davinci_rtc->base + addr);
 }

 static inline void rtcif_wait(struct davinci_rtc *davinci_rtc)
 {
 	while (rtcif_read(davinci_rtc, PRTCIF_CTLR) & PRTCIF_CTLR_BUSY)
 		cpu_relax();
 }

 static inline void rtcss_write(struct davinci_rtc *davinci_rtc,
 			       unsigned long val, u8 addr)
 {
 	rtcif_wait(davinci_rtc);

 	rtcif_write(davinci_rtc, PRTCIF_CTLR_BENL_LSB | addr, PRTCIF_CTLR);
 	rtcif_write(davinci_rtc, val, PRTCIF_LDATA);

 	rtcif_wait(davinci_rtc);
 }

 static inline u8 rtcss_read(struct davinci_rtc *davinci_rtc, u8 addr)
 {
 	rtcif_wait(davinci_rtc);

 	rtcif_write(davinci_rtc, PRTCIF_CTLR_DIR | PRTCIF_CTLR_BENL_LSB | addr,
 		    PRTCIF_CTLR);

 	rtcif_wait(davinci_rtc);

 	return rtcif_read(davinci_rtc, PRTCIF_LDATA);
 }

 static inline void davinci_rtcss_calendar_wait(struct davinci_rtc *davinci_rtc)
 {
 	while (rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL) &
 	       PRTCSS_RTC_CCTRL_CALBUSY)
 		cpu_relax();
 }

 static irqreturn_t davinci_rtc_interrupt(int irq, void *class_dev)
 {
 	struct davinci_rtc *davinci_rtc = class_dev;
 	unsigned long events = 0;
 	u32 irq_flg;
 	u8 alm_irq, tmr_irq;
 	u8 rtc_ctrl, rtc_cctrl;
 	int ret = IRQ_NONE;

 	irq_flg = rtcif_read(davinci_rtc, PRTCIF_INTFLG) &
 		  PRTCIF_INTFLG_RTCSS;

 	alm_irq = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL) &
 		  PRTCSS_RTC_CCTRL_ALMFLG;

 	tmr_irq = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL) &
 		  PRTCSS_RTC_CTRL_TMRFLG;

 	if (irq_flg) {
 		if (alm_irq) {
 			events |= RTC_IRQF | RTC_AF;
 			rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);
 			rtc_cctrl |=  PRTCSS_RTC_CCTRL_ALMFLG;
 			rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);
 		} else if (tmr_irq) {
 			events |= RTC_IRQF | RTC_PF;
 			rtc_ctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL);
 			rtc_ctrl |=  PRTCSS_RTC_CTRL_TMRFLG;
 			rtcss_write(davinci_rtc, rtc_ctrl, PRTCSS_RTC_CTRL);
 		}

 		rtcif_write(davinci_rtc, PRTCIF_INTFLG_RTCSS,
 				    PRTCIF_INTFLG);
 		rtc_update_irq(davinci_rtc->rtc, 1, events);

 		ret = IRQ_HANDLED;
 	}

 	return ret;
 }

 static int
 davinci_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
 	u8 rtc_ctrl;
 	unsigned long flags;
 	int ret = 0;

 	spin_lock_irqsave(&davinci_rtc_lock, flags);

 	rtc_ctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL);

 	switch (cmd) {
 	case RTC_WIE_ON:
 		rtc_ctrl |= PRTCSS_RTC_CTRL_WEN | PRTCSS_RTC_CTRL_WDTFLG;
 		break;
 	case RTC_WIE_OFF:
 		rtc_ctrl &= ~PRTCSS_RTC_CTRL_WEN;
 		break;
 	default:
 		ret = -ENOIOCTLCMD;
 	}

 	rtcss_write(davinci_rtc, rtc_ctrl, PRTCSS_RTC_CTRL);

 	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

 	return ret;
 }

 static int convertfromdays(u16 days, struct rtc_time *tm)
 {
 	int tmp_days, year, mon;

 	for (year = 2000;; year++) {
 		tmp_days = rtc_year_days(1, 12, year);
 		if (days >= tmp_days)
 			days -= tmp_days;
 		else {
 			for (mon = 0;; mon++) {
 				tmp_days = rtc_month_days(mon, year);
 				if (days >= tmp_days) {
 					days -= tmp_days;
 				} else {
 					tm->tm_year = year - 1900;
 					tm->tm_mon = mon;
 					tm->tm_mday = days + 1;
 					break;
 				}
 			}
 			break;
 		}
 	}
 	return 0;
 }

 static int convert2days(u16 *days, struct rtc_time *tm)
 {
 	int i;
 	*days = 0;

 	/* epoch == 1900 */
 	if (tm->tm_year < 100 || tm->tm_year > 199)
 		return -EINVAL;

 	for (i = 2000; i < 1900 + tm->tm_year; i++)
 		*days += rtc_year_days(1, 12, i);

 	*days += rtc_year_days(tm->tm_mday, tm->tm_mon, 1900 + tm->tm_year);

 	return 0;
 }

 static int davinci_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
 	u16 days = 0;
 	u8 day0, day1;
 	unsigned long flags;

 	spin_lock_irqsave(&davinci_rtc_lock, flags);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	tm->tm_sec = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_SEC));

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	tm->tm_min = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_MIN));

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	tm->tm_hour = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_HOUR));

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	day0 = rtcss_read(davinci_rtc, PRTCSS_RTC_DAY0);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	day1 = rtcss_read(davinci_rtc, PRTCSS_RTC_DAY1);

 	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

 	days |= day1;
 	days <<= 8;
 	days |= day0;

 	if (convertfromdays(days, tm) < 0)
 		return -EINVAL;

 	return 0;
 }

 static int davinci_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
 	u16 days;
 	u8 rtc_cctrl;
 	unsigned long flags;

 	if (convert2days(&days, tm) < 0)
 		return -EINVAL;

 	spin_lock_irqsave(&davinci_rtc_lock, flags);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, bin2bcd(tm->tm_sec), PRTCSS_RTC_SEC);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, bin2bcd(tm->tm_min), PRTCSS_RTC_MIN);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, bin2bcd(tm->tm_hour), PRTCSS_RTC_HOUR);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, days & 0xFF, PRTCSS_RTC_DAY0);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, (days & 0xFF00) >> 8, PRTCSS_RTC_DAY1);

 	rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);
 	rtc_cctrl |= PRTCSS_RTC_CCTRL_CAEN;
 	rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);

 	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

 	return 0;
 }

 static int davinci_rtc_alarm_irq_enable(struct device *dev,
 					unsigned int enabled)
 {
 	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
 	unsigned long flags;
 	u8 rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);

 	spin_lock_irqsave(&davinci_rtc_lock, flags);

 	if (enabled)
 		rtc_cctrl |= PRTCSS_RTC_CCTRL_DAEN |
 			     PRTCSS_RTC_CCTRL_HAEN |
 			     PRTCSS_RTC_CCTRL_MAEN |
 			     PRTCSS_RTC_CCTRL_ALMFLG |
 			     PRTCSS_RTC_CCTRL_AIEN;
 	else
 		rtc_cctrl &= ~PRTCSS_RTC_CCTRL_AIEN;

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);

 	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

 	return 0;
 }

 static int davinci_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
 	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
 	u16 days = 0;
 	u8 day0, day1;
 	unsigned long flags;

 	alm->time.tm_sec = 0;

 	spin_lock_irqsave(&davinci_rtc_lock, flags);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	alm->time.tm_min = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_AMIN));

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	alm->time.tm_hour = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_AHOUR));

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	day0 = rtcss_read(davinci_rtc, PRTCSS_RTC_ADAY0);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	day1 = rtcss_read(davinci_rtc, PRTCSS_RTC_ADAY1);

 	spin_unlock_irqrestore(&davinci_rtc_lock, flags);
 	days |= day1;
 	days <<= 8;
 	days |= day0;

 	if (convertfromdays(days, &alm->time) < 0)
 		return -EINVAL;

 	alm->pending = !!(rtcss_read(davinci_rtc,
 			  PRTCSS_RTC_CCTRL) &
 			PRTCSS_RTC_CCTRL_AIEN);
 	alm->enabled = alm->pending && device_may_wakeup(dev);

 	return 0;
 }

 static int davinci_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
 	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
 	unsigned long flags;
 	u16 days;

 	if (alm->time.tm_mday <= 0 && alm->time.tm_mon < 0
 	    && alm->time.tm_year < 0) {
 		struct rtc_time tm;
 		unsigned long now, then;

 		davinci_rtc_read_time(dev, &tm);
 		rtc_tm_to_time(&tm, &now);

 		alm->time.tm_mday = tm.tm_mday;
 		alm->time.tm_mon = tm.tm_mon;
 		alm->time.tm_year = tm.tm_year;
 		rtc_tm_to_time(&alm->time, &then);

 		if (then < now) {
 			rtc_time_to_tm(now + 24 * 60 * 60, &tm);
 			alm->time.tm_mday = tm.tm_mday;
 			alm->time.tm_mon = tm.tm_mon;
 			alm->time.tm_year = tm.tm_year;
 		}
 	}

 	if (convert2days(&days, &alm->time) < 0)
 		return -EINVAL;

 	spin_lock_irqsave(&davinci_rtc_lock, flags);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, bin2bcd(alm->time.tm_min), PRTCSS_RTC_AMIN);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, bin2bcd(alm->time.tm_hour), PRTCSS_RTC_AHOUR);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, days & 0xFF, PRTCSS_RTC_ADAY0);

 	davinci_rtcss_calendar_wait(davinci_rtc);
 	rtcss_write(davinci_rtc, (days & 0xFF00) >> 8, PRTCSS_RTC_ADAY1);

 	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

 	return 0;
 }

 static const struct rtc_class_ops davinci_rtc_ops = {
 	.ioctl			= davinci_rtc_ioctl,
 	.read_time		= davinci_rtc_read_time,
 	.set_time		= davinci_rtc_set_time,
 	.alarm_irq_enable	= davinci_rtc_alarm_irq_enable,
 	.read_alarm		= davinci_rtc_read_alarm,
 	.set_alarm		= davinci_rtc_set_alarm,
 };

 static int __init davinci_rtc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct davinci_rtc *davinci_rtc;
 	struct resource *res;
 	int ret = 0;

 	davinci_rtc = devm_kzalloc(&pdev->dev, sizeof(struct davinci_rtc), GFP_KERNEL);
 	if (!davinci_rtc)
 		return -ENOMEM;

 	davinci_rtc->irq = platform_get_irq(pdev, 0);
 	if (davinci_rtc->irq < 0)
 		return davinci_rtc->irq;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	davinci_rtc->base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(davinci_rtc->base))
 		return PTR_ERR(davinci_rtc->base);

 	platform_set_drvdata(pdev, davinci_rtc);

 	davinci_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 				    &davinci_rtc_ops, THIS_MODULE);
 	if (IS_ERR(davinci_rtc->rtc)) {
 		dev_err(dev, "unable to register RTC device, err %d\n",
 				ret);
 		return PTR_ERR(davinci_rtc->rtc);
 	}

 	rtcif_write(davinci_rtc, PRTCIF_INTFLG_RTCSS, PRTCIF_INTFLG);
 	rtcif_write(davinci_rtc, 0, PRTCIF_INTEN);
 	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_INTC_EXTENA1);

 	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_CTRL);
 	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_CCTRL);

 	ret = devm_request_irq(dev, davinci_rtc->irq, davinci_rtc_interrupt,
 			  0, "davinci_rtc", davinci_rtc);
 	if (ret < 0) {
 		dev_err(dev, "unable to register davinci RTC interrupt\n");
 		return ret;
 	}

 	/* Enable interrupts */
 	rtcif_write(davinci_rtc, PRTCIF_INTEN_RTCSS, PRTCIF_INTEN);
 	rtcss_write(davinci_rtc, PRTCSS_RTC_INTC_EXTENA1_MASK,
 			    PRTCSS_RTC_INTC_EXTENA1);

 	rtcss_write(davinci_rtc, PRTCSS_RTC_CCTRL_CAEN, PRTCSS_RTC_CCTRL);

 	device_init_wakeup(&pdev->dev, 0);

 	return 0;
 }

 static int __exit davinci_rtc_remove(struct platform_device *pdev)
 {
 	struct davinci_rtc *davinci_rtc = platform_get_drvdata(pdev);

 	device_init_wakeup(&pdev->dev, 0);

 	rtcif_write(davinci_rtc, 0, PRTCIF_INTEN);

 	return 0;
 }

 static struct platform_driver davinci_rtc_driver = {
 	.remove		= __exit_p(davinci_rtc_remove),
 	.driver		= {
 		.name = "rtc_davinci",
 	},
 };

 module_platform_driver_probe(davinci_rtc_driver, davinci_rtc_probe);

 MODULE_AUTHOR("Miguel Aguilar <miguel.aguilar@ridgerun.com>");
 MODULE_DESCRIPTION("Texas Instruments DaVinci PRTC Driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* DaVinci Power Management and Real Time Clock Driver for TI platforms
	*
	* Copyright (C) 2009 Texas Instruments, Inc
	*
	* Author: Miguel Aguilar <miguel.aguilar@ridgerun.com>
	*/
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/ioport.h>
	#include <linux/delay.h>
	#include <linux/spinlock.h>
	#include <linux/rtc.h>
	#include <linux/bcd.h>
	#include <linux/platform_device.h>
	#include <linux/io.h>
	#include <linux/slab.h>

	/*
	* The DaVinci RTC is a simple RTC with the following
	* Sec: 0 - 59 : BCD count
	* Min: 0 - 59 : BCD count
	* Hour: 0 - 23 : BCD count
	* Day: 0 - 0x7FFF(32767) : Binary count ( Over 89 years )
	*/

	/* PRTC interface registers */
	#define DAVINCI_PRTCIF_PID 0x00
	#define PRTCIF_CTLR 0x04
	#define PRTCIF_LDATA 0x08
	#define PRTCIF_UDATA 0x0C
	#define PRTCIF_INTEN 0x10
	#define PRTCIF_INTFLG 0x14

	/* PRTCIF_CTLR bit fields */
	#define PRTCIF_CTLR_BUSY BIT(31)
	#define PRTCIF_CTLR_SIZE BIT(25)
	#define PRTCIF_CTLR_DIR BIT(24)
	#define PRTCIF_CTLR_BENU_MSB BIT(23)
	#define PRTCIF_CTLR_BENU_3RD_BYTE BIT(22)
	#define PRTCIF_CTLR_BENU_2ND_BYTE BIT(21)
	#define PRTCIF_CTLR_BENU_LSB BIT(20)
	#define PRTCIF_CTLR_BENU_MASK (0x00F00000)
	#define PRTCIF_CTLR_BENL_MSB BIT(19)
	#define PRTCIF_CTLR_BENL_3RD_BYTE BIT(18)
	#define PRTCIF_CTLR_BENL_2ND_BYTE BIT(17)
	#define PRTCIF_CTLR_BENL_LSB BIT(16)
	#define PRTCIF_CTLR_BENL_MASK (0x000F0000)

	/* PRTCIF_INTEN bit fields */
	#define PRTCIF_INTEN_RTCSS BIT(1)
	#define PRTCIF_INTEN_RTCIF BIT(0)
	#define PRTCIF_INTEN_MASK (PRTCIF_INTEN_RTCSS \
	\| PRTCIF_INTEN_RTCIF)

	/* PRTCIF_INTFLG bit fields */
	#define PRTCIF_INTFLG_RTCSS BIT(1)
	#define PRTCIF_INTFLG_RTCIF BIT(0)
	#define PRTCIF_INTFLG_MASK (PRTCIF_INTFLG_RTCSS \
	\| PRTCIF_INTFLG_RTCIF)

	/* PRTC subsystem registers */
	#define PRTCSS_RTC_INTC_EXTENA1 (0x0C)
	#define PRTCSS_RTC_CTRL (0x10)
	#define PRTCSS_RTC_WDT (0x11)
	#define PRTCSS_RTC_TMR0 (0x12)
	#define PRTCSS_RTC_TMR1 (0x13)
	#define PRTCSS_RTC_CCTRL (0x14)
	#define PRTCSS_RTC_SEC (0x15)
	#define PRTCSS_RTC_MIN (0x16)
	#define PRTCSS_RTC_HOUR (0x17)
	#define PRTCSS_RTC_DAY0 (0x18)
	#define PRTCSS_RTC_DAY1 (0x19)
	#define PRTCSS_RTC_AMIN (0x1A)
	#define PRTCSS_RTC_AHOUR (0x1B)
	#define PRTCSS_RTC_ADAY0 (0x1C)
	#define PRTCSS_RTC_ADAY1 (0x1D)
	#define PRTCSS_RTC_CLKC_CNT (0x20)

	/* PRTCSS_RTC_INTC_EXTENA1 */
	#define PRTCSS_RTC_INTC_EXTENA1_MASK (0x07)

	/* PRTCSS_RTC_CTRL bit fields */
	#define PRTCSS_RTC_CTRL_WDTBUS BIT(7)
	#define PRTCSS_RTC_CTRL_WEN BIT(6)
	#define PRTCSS_RTC_CTRL_WDRT BIT(5)
	#define PRTCSS_RTC_CTRL_WDTFLG BIT(4)
	#define PRTCSS_RTC_CTRL_TE BIT(3)
	#define PRTCSS_RTC_CTRL_TIEN BIT(2)
	#define PRTCSS_RTC_CTRL_TMRFLG BIT(1)
	#define PRTCSS_RTC_CTRL_TMMD BIT(0)

	/* PRTCSS_RTC_CCTRL bit fields */
	#define PRTCSS_RTC_CCTRL_CALBUSY BIT(7)
	#define PRTCSS_RTC_CCTRL_DAEN BIT(5)
	#define PRTCSS_RTC_CCTRL_HAEN BIT(4)
	#define PRTCSS_RTC_CCTRL_MAEN BIT(3)
	#define PRTCSS_RTC_CCTRL_ALMFLG BIT(2)
	#define PRTCSS_RTC_CCTRL_AIEN BIT(1)
	#define PRTCSS_RTC_CCTRL_CAEN BIT(0)

	static DEFINE_SPINLOCK(davinci_rtc_lock);

	struct davinci_rtc {
	struct rtc_device *rtc;
	void __iomem *base;
	int irq;
	};

	static inline void rtcif_write(struct davinci_rtc *davinci_rtc,
	u32 val, u32 addr)
	{
	writel(val, davinci_rtc->base + addr);
	}

	static inline u32 rtcif_read(struct davinci_rtc *davinci_rtc, u32 addr)
	{
	return readl(davinci_rtc->base + addr);
	}

	static inline void rtcif_wait(struct davinci_rtc *davinci_rtc)
	{
	while (rtcif_read(davinci_rtc, PRTCIF_CTLR) & PRTCIF_CTLR_BUSY)
	cpu_relax();
	}

	static inline void rtcss_write(struct davinci_rtc *davinci_rtc,
	unsigned long val, u8 addr)
	{
	rtcif_wait(davinci_rtc);

	rtcif_write(davinci_rtc, PRTCIF_CTLR_BENL_LSB \| addr, PRTCIF_CTLR);
	rtcif_write(davinci_rtc, val, PRTCIF_LDATA);

	rtcif_wait(davinci_rtc);
	}

	static inline u8 rtcss_read(struct davinci_rtc *davinci_rtc, u8 addr)
	{
	rtcif_wait(davinci_rtc);

	rtcif_write(davinci_rtc, PRTCIF_CTLR_DIR \| PRTCIF_CTLR_BENL_LSB \| addr,
	PRTCIF_CTLR);

	rtcif_wait(davinci_rtc);

	return rtcif_read(davinci_rtc, PRTCIF_LDATA);
	}

	static inline void davinci_rtcss_calendar_wait(struct davinci_rtc *davinci_rtc)
	{
	while (rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL) &
	PRTCSS_RTC_CCTRL_CALBUSY)
	cpu_relax();
	}

	static irqreturn_t davinci_rtc_interrupt(int irq, void *class_dev)
	{
	struct davinci_rtc *davinci_rtc = class_dev;
	unsigned long events = 0;
	u32 irq_flg;
	u8 alm_irq, tmr_irq;
	u8 rtc_ctrl, rtc_cctrl;
	int ret = IRQ_NONE;

	irq_flg = rtcif_read(davinci_rtc, PRTCIF_INTFLG) &
	PRTCIF_INTFLG_RTCSS;

	alm_irq = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL) &
	PRTCSS_RTC_CCTRL_ALMFLG;

	tmr_irq = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL) &
	PRTCSS_RTC_CTRL_TMRFLG;

	if (irq_flg) {
	if (alm_irq) {
	events \|= RTC_IRQF \| RTC_AF;
	rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);
	rtc_cctrl \|= PRTCSS_RTC_CCTRL_ALMFLG;
	rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);
	} else if (tmr_irq) {
	events \|= RTC_IRQF \| RTC_PF;
	rtc_ctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL);
	rtc_ctrl \|= PRTCSS_RTC_CTRL_TMRFLG;
	rtcss_write(davinci_rtc, rtc_ctrl, PRTCSS_RTC_CTRL);
	}

	rtcif_write(davinci_rtc, PRTCIF_INTFLG_RTCSS,
	PRTCIF_INTFLG);
	rtc_update_irq(davinci_rtc->rtc, 1, events);

	ret = IRQ_HANDLED;
	}

	return ret;
	}

	static int
	davinci_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
	{
	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
	u8 rtc_ctrl;
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&davinci_rtc_lock, flags);

	rtc_ctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CTRL);

	switch (cmd) {
	case RTC_WIE_ON:
	rtc_ctrl \|= PRTCSS_RTC_CTRL_WEN \| PRTCSS_RTC_CTRL_WDTFLG;
	break;
	case RTC_WIE_OFF:
	rtc_ctrl &= ~PRTCSS_RTC_CTRL_WEN;
	break;
	default:
	ret = -ENOIOCTLCMD;
	}

	rtcss_write(davinci_rtc, rtc_ctrl, PRTCSS_RTC_CTRL);

	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

	return ret;
	}

	static int convertfromdays(u16 days, struct rtc_time *tm)
	{
	int tmp_days, year, mon;

	for (year = 2000;; year++) {
	tmp_days = rtc_year_days(1, 12, year);
	if (days >= tmp_days)
	days -= tmp_days;
	else {
	for (mon = 0;; mon++) {
	tmp_days = rtc_month_days(mon, year);
	if (days >= tmp_days) {
	days -= tmp_days;
	} else {
	tm->tm_year = year - 1900;
	tm->tm_mon = mon;
	tm->tm_mday = days + 1;
	break;
	}
	}
	break;
	}
	}
	return 0;
	}

	static int convert2days(u16 days, struct rtc_time tm)
	{
	int i;
	*days = 0;

	/* epoch == 1900 */
	if (tm->tm_year < 100 \|\| tm->tm_year > 199)
	return -EINVAL;

	for (i = 2000; i < 1900 + tm->tm_year; i++)
	*days += rtc_year_days(1, 12, i);

	*days += rtc_year_days(tm->tm_mday, tm->tm_mon, 1900 + tm->tm_year);

	return 0;
	}

	static int davinci_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
	u16 days = 0;
	u8 day0, day1;
	unsigned long flags;

	spin_lock_irqsave(&davinci_rtc_lock, flags);

	davinci_rtcss_calendar_wait(davinci_rtc);
	tm->tm_sec = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_SEC));

	davinci_rtcss_calendar_wait(davinci_rtc);
	tm->tm_min = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_MIN));

	davinci_rtcss_calendar_wait(davinci_rtc);
	tm->tm_hour = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_HOUR));

	davinci_rtcss_calendar_wait(davinci_rtc);
	day0 = rtcss_read(davinci_rtc, PRTCSS_RTC_DAY0);

	davinci_rtcss_calendar_wait(davinci_rtc);
	day1 = rtcss_read(davinci_rtc, PRTCSS_RTC_DAY1);

	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

	days \|= day1;
	days <<= 8;
	days \|= day0;

	if (convertfromdays(days, tm) < 0)
	return -EINVAL;

	return 0;
	}

	static int davinci_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
	u16 days;
	u8 rtc_cctrl;
	unsigned long flags;

	if (convert2days(&days, tm) < 0)
	return -EINVAL;

	spin_lock_irqsave(&davinci_rtc_lock, flags);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, bin2bcd(tm->tm_sec), PRTCSS_RTC_SEC);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, bin2bcd(tm->tm_min), PRTCSS_RTC_MIN);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, bin2bcd(tm->tm_hour), PRTCSS_RTC_HOUR);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, days & 0xFF, PRTCSS_RTC_DAY0);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, (days & 0xFF00) >> 8, PRTCSS_RTC_DAY1);

	rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);
	rtc_cctrl \|= PRTCSS_RTC_CCTRL_CAEN;
	rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);

	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

	return 0;
	}

	static int davinci_rtc_alarm_irq_enable(struct device *dev,
	unsigned int enabled)
	{
	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
	unsigned long flags;
	u8 rtc_cctrl = rtcss_read(davinci_rtc, PRTCSS_RTC_CCTRL);

	spin_lock_irqsave(&davinci_rtc_lock, flags);

	if (enabled)
	rtc_cctrl \|= PRTCSS_RTC_CCTRL_DAEN \|
	PRTCSS_RTC_CCTRL_HAEN \|
	PRTCSS_RTC_CCTRL_MAEN \|
	PRTCSS_RTC_CCTRL_ALMFLG \|
	PRTCSS_RTC_CCTRL_AIEN;
	else
	rtc_cctrl &= ~PRTCSS_RTC_CCTRL_AIEN;

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, rtc_cctrl, PRTCSS_RTC_CCTRL);

	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

	return 0;
	}

	static int davinci_rtc_read_alarm(struct device dev, struct rtc_wkalrm alm)
	{
	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
	u16 days = 0;
	u8 day0, day1;
	unsigned long flags;

	alm->time.tm_sec = 0;

	spin_lock_irqsave(&davinci_rtc_lock, flags);

	davinci_rtcss_calendar_wait(davinci_rtc);
	alm->time.tm_min = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_AMIN));

	davinci_rtcss_calendar_wait(davinci_rtc);
	alm->time.tm_hour = bcd2bin(rtcss_read(davinci_rtc, PRTCSS_RTC_AHOUR));

	davinci_rtcss_calendar_wait(davinci_rtc);
	day0 = rtcss_read(davinci_rtc, PRTCSS_RTC_ADAY0);

	davinci_rtcss_calendar_wait(davinci_rtc);
	day1 = rtcss_read(davinci_rtc, PRTCSS_RTC_ADAY1);

	spin_unlock_irqrestore(&davinci_rtc_lock, flags);
	days \|= day1;
	days <<= 8;
	days \|= day0;

	if (convertfromdays(days, &alm->time) < 0)
	return -EINVAL;

	alm->pending = !!(rtcss_read(davinci_rtc,
	PRTCSS_RTC_CCTRL) &
	PRTCSS_RTC_CCTRL_AIEN);
	alm->enabled = alm->pending && device_may_wakeup(dev);

	return 0;
	}

	static int davinci_rtc_set_alarm(struct device dev, struct rtc_wkalrm alm)
	{
	struct davinci_rtc *davinci_rtc = dev_get_drvdata(dev);
	unsigned long flags;
	u16 days;

	if (alm->time.tm_mday <= 0 && alm->time.tm_mon < 0
	&& alm->time.tm_year < 0) {
	struct rtc_time tm;
	unsigned long now, then;

	davinci_rtc_read_time(dev, &tm);
	rtc_tm_to_time(&tm, &now);

	alm->time.tm_mday = tm.tm_mday;
	alm->time.tm_mon = tm.tm_mon;
	alm->time.tm_year = tm.tm_year;
	rtc_tm_to_time(&alm->time, &then);

	if (then < now) {
	rtc_time_to_tm(now + 24 * 60 * 60, &tm);
	alm->time.tm_mday = tm.tm_mday;
	alm->time.tm_mon = tm.tm_mon;
	alm->time.tm_year = tm.tm_year;
	}
	}

	if (convert2days(&days, &alm->time) < 0)
	return -EINVAL;

	spin_lock_irqsave(&davinci_rtc_lock, flags);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, bin2bcd(alm->time.tm_min), PRTCSS_RTC_AMIN);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, bin2bcd(alm->time.tm_hour), PRTCSS_RTC_AHOUR);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, days & 0xFF, PRTCSS_RTC_ADAY0);

	davinci_rtcss_calendar_wait(davinci_rtc);
	rtcss_write(davinci_rtc, (days & 0xFF00) >> 8, PRTCSS_RTC_ADAY1);

	spin_unlock_irqrestore(&davinci_rtc_lock, flags);

	return 0;
	}

	static const struct rtc_class_ops davinci_rtc_ops = {
	.ioctl = davinci_rtc_ioctl,
	.read_time = davinci_rtc_read_time,
	.set_time = davinci_rtc_set_time,
	.alarm_irq_enable = davinci_rtc_alarm_irq_enable,
	.read_alarm = davinci_rtc_read_alarm,
	.set_alarm = davinci_rtc_set_alarm,
	};

	static int __init davinci_rtc_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct davinci_rtc *davinci_rtc;
	struct resource *res;
	int ret = 0;

	davinci_rtc = devm_kzalloc(&pdev->dev, sizeof(struct davinci_rtc), GFP_KERNEL);
	if (!davinci_rtc)
	return -ENOMEM;

	davinci_rtc->irq = platform_get_irq(pdev, 0);
	if (davinci_rtc->irq < 0)
	return davinci_rtc->irq;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	davinci_rtc->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(davinci_rtc->base))
	return PTR_ERR(davinci_rtc->base);

	platform_set_drvdata(pdev, davinci_rtc);

	davinci_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
	&davinci_rtc_ops, THIS_MODULE);
	if (IS_ERR(davinci_rtc->rtc)) {
	dev_err(dev, "unable to register RTC device, err %d\n",
	ret);
	return PTR_ERR(davinci_rtc->rtc);
	}

	rtcif_write(davinci_rtc, PRTCIF_INTFLG_RTCSS, PRTCIF_INTFLG);
	rtcif_write(davinci_rtc, 0, PRTCIF_INTEN);
	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_INTC_EXTENA1);

	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_CTRL);
	rtcss_write(davinci_rtc, 0, PRTCSS_RTC_CCTRL);

	ret = devm_request_irq(dev, davinci_rtc->irq, davinci_rtc_interrupt,
	0, "davinci_rtc", davinci_rtc);
	if (ret < 0) {
	dev_err(dev, "unable to register davinci RTC interrupt\n");
	return ret;
	}

	/* Enable interrupts */
	rtcif_write(davinci_rtc, PRTCIF_INTEN_RTCSS, PRTCIF_INTEN);
	rtcss_write(davinci_rtc, PRTCSS_RTC_INTC_EXTENA1_MASK,
	PRTCSS_RTC_INTC_EXTENA1);

	rtcss_write(davinci_rtc, PRTCSS_RTC_CCTRL_CAEN, PRTCSS_RTC_CCTRL);

	device_init_wakeup(&pdev->dev, 0);

	return 0;
	}

	static int __exit davinci_rtc_remove(struct platform_device *pdev)
	{
	struct davinci_rtc *davinci_rtc = platform_get_drvdata(pdev);

	device_init_wakeup(&pdev->dev, 0);

	rtcif_write(davinci_rtc, 0, PRTCIF_INTEN);

	return 0;
	}

	static struct platform_driver davinci_rtc_driver = {
	.remove = __exit_p(davinci_rtc_remove),
	.driver = {
	.name = "rtc_davinci",
	},
	};

	module_platform_driver_probe(davinci_rtc_driver, davinci_rtc_probe);

	MODULE_AUTHOR("Miguel Aguilar <miguel.aguilar@ridgerun.com>");
	MODULE_DESCRIPTION("Texas Instruments DaVinci PRTC Driver");
	MODULE_LICENSE("GPL");