drivers/rtc/rtc-asm9260.c - SHIFTPHONES/kernel/shift/mainline - Gitiles

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) 2016 Oleksij Rempel <linux@rempel-privat.de>
  */

 #include <linux/clk.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/rtc.h>

 /* Miscellaneous registers */
 /* Interrupt Location Register */
 #define HW_ILR			0x00
 #define BM_RTCALF		BIT(1)
 #define BM_RTCCIF		BIT(0)

 /* Clock Control Register */
 #define HW_CCR			0x08
 /* Calibration counter disable */
 #define BM_CCALOFF		BIT(4)
 /* Reset internal oscillator divider */
 #define BM_CTCRST		BIT(1)
 /* Clock Enable */
 #define BM_CLKEN		BIT(0)

 /* Counter Increment Interrupt Register */
 #define HW_CIIR			0x0C
 #define BM_CIIR_IMYEAR		BIT(7)
 #define BM_CIIR_IMMON		BIT(6)
 #define BM_CIIR_IMDOY		BIT(5)
 #define BM_CIIR_IMDOW		BIT(4)
 #define BM_CIIR_IMDOM		BIT(3)
 #define BM_CIIR_IMHOUR		BIT(2)
 #define BM_CIIR_IMMIN		BIT(1)
 #define BM_CIIR_IMSEC		BIT(0)

 /* Alarm Mask Register */
 #define HW_AMR			0x10
 #define BM_AMR_IMYEAR		BIT(7)
 #define BM_AMR_IMMON		BIT(6)
 #define BM_AMR_IMDOY		BIT(5)
 #define BM_AMR_IMDOW		BIT(4)
 #define BM_AMR_IMDOM		BIT(3)
 #define BM_AMR_IMHOUR		BIT(2)
 #define BM_AMR_IMMIN		BIT(1)
 #define BM_AMR_IMSEC		BIT(0)
 #define BM_AMR_OFF		0xff

 /* Consolidated time registers */
 #define HW_CTIME0		0x14
 #define BM_CTIME0_DOW_S		24
 #define BM_CTIME0_DOW_M		0x7
 #define BM_CTIME0_HOUR_S	16
 #define BM_CTIME0_HOUR_M	0x1f
 #define BM_CTIME0_MIN_S		8
 #define BM_CTIME0_MIN_M		0x3f
 #define BM_CTIME0_SEC_S		0
 #define BM_CTIME0_SEC_M		0x3f

 #define HW_CTIME1		0x18
 #define BM_CTIME1_YEAR_S	16
 #define BM_CTIME1_YEAR_M	0xfff
 #define BM_CTIME1_MON_S		8
 #define BM_CTIME1_MON_M		0xf
 #define BM_CTIME1_DOM_S		0
 #define BM_CTIME1_DOM_M		0x1f

 #define HW_CTIME2		0x1C
 #define BM_CTIME2_DOY_S		0
 #define BM_CTIME2_DOY_M		0xfff

 /* Time counter registers */
 #define HW_SEC			0x20
 #define HW_MIN			0x24
 #define HW_HOUR			0x28
 #define HW_DOM			0x2C
 #define HW_DOW			0x30
 #define HW_DOY			0x34
 #define HW_MONTH		0x38
 #define HW_YEAR			0x3C

 #define HW_CALIBRATION		0x40
 #define BM_CALDIR_BACK		BIT(17)
 #define BM_CALVAL_M		0x1ffff

 /* General purpose registers */
 #define HW_GPREG0		0x44
 #define HW_GPREG1		0x48
 #define HW_GPREG2		0x4C
 #define HW_GPREG3		0x50
 #define HW_GPREG4		0x54

 /* Alarm register group */
 #define HW_ALSEC		0x60
 #define HW_ALMIN		0x64
 #define HW_ALHOUR		0x68
 #define HW_ALDOM		0x6C
 #define HW_ALDOW		0x70
 #define HW_ALDOY		0x74
 #define HW_ALMON		0x78
 #define HW_ALYEAR		0x7C

 struct asm9260_rtc_priv {
 	struct device		*dev;
 	void __iomem		*iobase;
 	struct rtc_device	*rtc;
 	struct clk		*clk;
 };

 static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
 {
 	struct asm9260_rtc_priv *priv = dev_id;
 	u32 isr;
 	unsigned long events = 0;

 	mutex_lock(&priv->rtc->ops_lock);
 	isr = ioread32(priv->iobase + HW_CIIR);
 	if (!isr) {
 		mutex_unlock(&priv->rtc->ops_lock);
 		return IRQ_NONE;
 	}

 	iowrite32(0, priv->iobase + HW_CIIR);
 	mutex_unlock(&priv->rtc->ops_lock);

 	events |= RTC_AF | RTC_IRQF;

 	rtc_update_irq(priv->rtc, 1, events);

 	return IRQ_HANDLED;
 }

 static int asm9260_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
 	u32 ctime0, ctime1, ctime2;

 	ctime0 = ioread32(priv->iobase + HW_CTIME0);
 	ctime1 = ioread32(priv->iobase + HW_CTIME1);
 	ctime2 = ioread32(priv->iobase + HW_CTIME2);

 	if (ctime1 != ioread32(priv->iobase + HW_CTIME1)) {
 		/*
 		 * woops, counter flipped right now. Now we are safe
 		 * to reread.
 		 */
 		ctime0 = ioread32(priv->iobase + HW_CTIME0);
 		ctime1 = ioread32(priv->iobase + HW_CTIME1);
 		ctime2 = ioread32(priv->iobase + HW_CTIME2);
 	}

 	tm->tm_sec  = (ctime0 >> BM_CTIME0_SEC_S)  & BM_CTIME0_SEC_M;
 	tm->tm_min  = (ctime0 >> BM_CTIME0_MIN_S)  & BM_CTIME0_MIN_M;
 	tm->tm_hour = (ctime0 >> BM_CTIME0_HOUR_S) & BM_CTIME0_HOUR_M;
 	tm->tm_wday = (ctime0 >> BM_CTIME0_DOW_S)  & BM_CTIME0_DOW_M;

 	tm->tm_mday = (ctime1 >> BM_CTIME1_DOM_S)  & BM_CTIME1_DOM_M;
 	tm->tm_mon  = (ctime1 >> BM_CTIME1_MON_S)  & BM_CTIME1_MON_M;
 	tm->tm_year = (ctime1 >> BM_CTIME1_YEAR_S) & BM_CTIME1_YEAR_M;

 	tm->tm_yday = (ctime2 >> BM_CTIME2_DOY_S)  & BM_CTIME2_DOY_M;

 	return 0;
 }

 static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);

 	/*
 	 * make sure SEC counter will not flip other counter on write time,
 	 * real value will be written at the enf of sequence.
 	 */
 	iowrite32(0, priv->iobase + HW_SEC);

 	iowrite32(tm->tm_year, priv->iobase + HW_YEAR);
 	iowrite32(tm->tm_mon,  priv->iobase + HW_MONTH);
 	iowrite32(tm->tm_mday, priv->iobase + HW_DOM);
 	iowrite32(tm->tm_wday, priv->iobase + HW_DOW);
 	iowrite32(tm->tm_yday, priv->iobase + HW_DOY);
 	iowrite32(tm->tm_hour, priv->iobase + HW_HOUR);
 	iowrite32(tm->tm_min,  priv->iobase + HW_MIN);
 	iowrite32(tm->tm_sec,  priv->iobase + HW_SEC);

 	return 0;
 }

 static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);

 	alrm->time.tm_year = ioread32(priv->iobase + HW_ALYEAR);
 	alrm->time.tm_mon  = ioread32(priv->iobase + HW_ALMON);
 	alrm->time.tm_mday = ioread32(priv->iobase + HW_ALDOM);
 	alrm->time.tm_wday = ioread32(priv->iobase + HW_ALDOW);
 	alrm->time.tm_yday = ioread32(priv->iobase + HW_ALDOY);
 	alrm->time.tm_hour = ioread32(priv->iobase + HW_ALHOUR);
 	alrm->time.tm_min  = ioread32(priv->iobase + HW_ALMIN);
 	alrm->time.tm_sec  = ioread32(priv->iobase + HW_ALSEC);

 	alrm->enabled = ioread32(priv->iobase + HW_AMR) ? 1 : 0;
 	alrm->pending = ioread32(priv->iobase + HW_CIIR) ? 1 : 0;

 	return rtc_valid_tm(&alrm->time);
 }

 static int asm9260_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);

 	iowrite32(alrm->time.tm_year, priv->iobase + HW_ALYEAR);
 	iowrite32(alrm->time.tm_mon,  priv->iobase + HW_ALMON);
 	iowrite32(alrm->time.tm_mday, priv->iobase + HW_ALDOM);
 	iowrite32(alrm->time.tm_wday, priv->iobase + HW_ALDOW);
 	iowrite32(alrm->time.tm_yday, priv->iobase + HW_ALDOY);
 	iowrite32(alrm->time.tm_hour, priv->iobase + HW_ALHOUR);
 	iowrite32(alrm->time.tm_min,  priv->iobase + HW_ALMIN);
 	iowrite32(alrm->time.tm_sec,  priv->iobase + HW_ALSEC);

 	iowrite32(alrm->enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);

 	return 0;
 }

 static int asm9260_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);

 	iowrite32(enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
 	return 0;
 }

 static const struct rtc_class_ops asm9260_rtc_ops = {
 	.read_time		= asm9260_rtc_read_time,
 	.set_time		= asm9260_rtc_set_time,
 	.read_alarm		= asm9260_rtc_read_alarm,
 	.set_alarm		= asm9260_rtc_set_alarm,
 	.alarm_irq_enable	= asm9260_alarm_irq_enable,
 };

 static int asm9260_rtc_probe(struct platform_device *pdev)
 {
 	struct asm9260_rtc_priv *priv;
 	struct device *dev = &pdev->dev;
 	struct resource	*res;
 	int irq_alarm, ret;
 	u32 ccr;

 	priv = devm_kzalloc(dev, sizeof(struct asm9260_rtc_priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	priv->dev = &pdev->dev;
 	platform_set_drvdata(pdev, priv);

 	irq_alarm = platform_get_irq(pdev, 0);
 	if (irq_alarm < 0) {
 		dev_err(dev, "No alarm IRQ resource defined\n");
 		return irq_alarm;
 	}

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

 	priv->clk = devm_clk_get(dev, "ahb");
 	ret = clk_prepare_enable(priv->clk);
 	if (ret) {
 		dev_err(dev, "Failed to enable clk!\n");
 		return ret;
 	}

 	ccr = ioread32(priv->iobase + HW_CCR);
 	/* if dev is not enabled, reset it */
 	if ((ccr & (BM_CLKEN | BM_CTCRST)) != BM_CLKEN) {
 		iowrite32(BM_CTCRST, priv->iobase + HW_CCR);
 		ccr = 0;
 	}

 	iowrite32(BM_CLKEN | ccr, priv->iobase + HW_CCR);
 	iowrite32(0, priv->iobase + HW_CIIR);
 	iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);

 	priv->rtc = devm_rtc_device_register(dev, dev_name(dev),
 					     &asm9260_rtc_ops, THIS_MODULE);
 	if (IS_ERR(priv->rtc)) {
 		ret = PTR_ERR(priv->rtc);
 		dev_err(dev, "Failed to register RTC device: %d\n", ret);
 		goto err_return;
 	}

 	ret = devm_request_threaded_irq(dev, irq_alarm, NULL,
 					asm9260_rtc_irq, IRQF_ONESHOT,
 					dev_name(dev), priv);
 	if (ret < 0) {
 		dev_err(dev, "can't get irq %i, err %d\n",
 			irq_alarm, ret);
 		goto err_return;
 	}

 	return 0;

 err_return:
 	clk_disable_unprepare(priv->clk);
 	return ret;
 }

 static int asm9260_rtc_remove(struct platform_device *pdev)
 {
 	struct asm9260_rtc_priv *priv = platform_get_drvdata(pdev);

 	/* Disable alarm matching */
 	iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);
 	clk_disable_unprepare(priv->clk);
 	return 0;
 }

 static const struct of_device_id asm9260_dt_ids[] = {
 	{ .compatible = "alphascale,asm9260-rtc", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, asm9260_dt_ids);

 static struct platform_driver asm9260_rtc_driver = {
 	.probe		= asm9260_rtc_probe,
 	.remove		= asm9260_rtc_remove,
 	.driver		= {
 		.name	= "asm9260-rtc",
 		.of_match_table = asm9260_dt_ids,
 	},
 };

 module_platform_driver(asm9260_rtc_driver);

 MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
 MODULE_DESCRIPTION("Alphascale asm9260 SoC Realtime Clock Driver (RTC)");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (C) 2016 Oleksij Rempel <linux@rempel-privat.de>
	*/

	#include <linux/clk.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/rtc.h>

	/* Miscellaneous registers */
	/* Interrupt Location Register */
	#define HW_ILR 0x00
	#define BM_RTCALF BIT(1)
	#define BM_RTCCIF BIT(0)

	/* Clock Control Register */
	#define HW_CCR 0x08
	/* Calibration counter disable */
	#define BM_CCALOFF BIT(4)
	/* Reset internal oscillator divider */
	#define BM_CTCRST BIT(1)
	/* Clock Enable */
	#define BM_CLKEN BIT(0)

	/* Counter Increment Interrupt Register */
	#define HW_CIIR 0x0C
	#define BM_CIIR_IMYEAR BIT(7)
	#define BM_CIIR_IMMON BIT(6)
	#define BM_CIIR_IMDOY BIT(5)
	#define BM_CIIR_IMDOW BIT(4)
	#define BM_CIIR_IMDOM BIT(3)
	#define BM_CIIR_IMHOUR BIT(2)
	#define BM_CIIR_IMMIN BIT(1)
	#define BM_CIIR_IMSEC BIT(0)

	/* Alarm Mask Register */
	#define HW_AMR 0x10
	#define BM_AMR_IMYEAR BIT(7)
	#define BM_AMR_IMMON BIT(6)
	#define BM_AMR_IMDOY BIT(5)
	#define BM_AMR_IMDOW BIT(4)
	#define BM_AMR_IMDOM BIT(3)
	#define BM_AMR_IMHOUR BIT(2)
	#define BM_AMR_IMMIN BIT(1)
	#define BM_AMR_IMSEC BIT(0)
	#define BM_AMR_OFF 0xff

	/* Consolidated time registers */
	#define HW_CTIME0 0x14
	#define BM_CTIME0_DOW_S 24
	#define BM_CTIME0_DOW_M 0x7
	#define BM_CTIME0_HOUR_S 16
	#define BM_CTIME0_HOUR_M 0x1f
	#define BM_CTIME0_MIN_S 8
	#define BM_CTIME0_MIN_M 0x3f
	#define BM_CTIME0_SEC_S 0
	#define BM_CTIME0_SEC_M 0x3f

	#define HW_CTIME1 0x18
	#define BM_CTIME1_YEAR_S 16
	#define BM_CTIME1_YEAR_M 0xfff
	#define BM_CTIME1_MON_S 8
	#define BM_CTIME1_MON_M 0xf
	#define BM_CTIME1_DOM_S 0
	#define BM_CTIME1_DOM_M 0x1f

	#define HW_CTIME2 0x1C
	#define BM_CTIME2_DOY_S 0
	#define BM_CTIME2_DOY_M 0xfff

	/* Time counter registers */
	#define HW_SEC 0x20
	#define HW_MIN 0x24
	#define HW_HOUR 0x28
	#define HW_DOM 0x2C
	#define HW_DOW 0x30
	#define HW_DOY 0x34
	#define HW_MONTH 0x38
	#define HW_YEAR 0x3C

	#define HW_CALIBRATION 0x40
	#define BM_CALDIR_BACK BIT(17)
	#define BM_CALVAL_M 0x1ffff

	/* General purpose registers */
	#define HW_GPREG0 0x44
	#define HW_GPREG1 0x48
	#define HW_GPREG2 0x4C
	#define HW_GPREG3 0x50
	#define HW_GPREG4 0x54

	/* Alarm register group */
	#define HW_ALSEC 0x60
	#define HW_ALMIN 0x64
	#define HW_ALHOUR 0x68
	#define HW_ALDOM 0x6C
	#define HW_ALDOW 0x70
	#define HW_ALDOY 0x74
	#define HW_ALMON 0x78
	#define HW_ALYEAR 0x7C

	struct asm9260_rtc_priv {
	struct device *dev;
	void __iomem *iobase;
	struct rtc_device *rtc;
	struct clk *clk;
	};

	static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
	{
	struct asm9260_rtc_priv *priv = dev_id;
	u32 isr;
	unsigned long events = 0;

	mutex_lock(&priv->rtc->ops_lock);
	isr = ioread32(priv->iobase + HW_CIIR);
	if (!isr) {
	mutex_unlock(&priv->rtc->ops_lock);
	return IRQ_NONE;
	}

	iowrite32(0, priv->iobase + HW_CIIR);
	mutex_unlock(&priv->rtc->ops_lock);

	events \|= RTC_AF \| RTC_IRQF;

	rtc_update_irq(priv->rtc, 1, events);

	return IRQ_HANDLED;
	}

	static int asm9260_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
	u32 ctime0, ctime1, ctime2;

	ctime0 = ioread32(priv->iobase + HW_CTIME0);
	ctime1 = ioread32(priv->iobase + HW_CTIME1);
	ctime2 = ioread32(priv->iobase + HW_CTIME2);

	if (ctime1 != ioread32(priv->iobase + HW_CTIME1)) {
	/*
	* woops, counter flipped right now. Now we are safe
	* to reread.
	*/
	ctime0 = ioread32(priv->iobase + HW_CTIME0);
	ctime1 = ioread32(priv->iobase + HW_CTIME1);
	ctime2 = ioread32(priv->iobase + HW_CTIME2);
	}

	tm->tm_sec = (ctime0 >> BM_CTIME0_SEC_S) & BM_CTIME0_SEC_M;
	tm->tm_min = (ctime0 >> BM_CTIME0_MIN_S) & BM_CTIME0_MIN_M;
	tm->tm_hour = (ctime0 >> BM_CTIME0_HOUR_S) & BM_CTIME0_HOUR_M;
	tm->tm_wday = (ctime0 >> BM_CTIME0_DOW_S) & BM_CTIME0_DOW_M;

	tm->tm_mday = (ctime1 >> BM_CTIME1_DOM_S) & BM_CTIME1_DOM_M;
	tm->tm_mon = (ctime1 >> BM_CTIME1_MON_S) & BM_CTIME1_MON_M;
	tm->tm_year = (ctime1 >> BM_CTIME1_YEAR_S) & BM_CTIME1_YEAR_M;

	tm->tm_yday = (ctime2 >> BM_CTIME2_DOY_S) & BM_CTIME2_DOY_M;

	return 0;
	}

	static int asm9260_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);

	/*
	* make sure SEC counter will not flip other counter on write time,
	* real value will be written at the enf of sequence.
	*/
	iowrite32(0, priv->iobase + HW_SEC);

	iowrite32(tm->tm_year, priv->iobase + HW_YEAR);
	iowrite32(tm->tm_mon, priv->iobase + HW_MONTH);
	iowrite32(tm->tm_mday, priv->iobase + HW_DOM);
	iowrite32(tm->tm_wday, priv->iobase + HW_DOW);
	iowrite32(tm->tm_yday, priv->iobase + HW_DOY);
	iowrite32(tm->tm_hour, priv->iobase + HW_HOUR);
	iowrite32(tm->tm_min, priv->iobase + HW_MIN);
	iowrite32(tm->tm_sec, priv->iobase + HW_SEC);

	return 0;
	}

	static int asm9260_rtc_read_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);

	alrm->time.tm_year = ioread32(priv->iobase + HW_ALYEAR);
	alrm->time.tm_mon = ioread32(priv->iobase + HW_ALMON);
	alrm->time.tm_mday = ioread32(priv->iobase + HW_ALDOM);
	alrm->time.tm_wday = ioread32(priv->iobase + HW_ALDOW);
	alrm->time.tm_yday = ioread32(priv->iobase + HW_ALDOY);
	alrm->time.tm_hour = ioread32(priv->iobase + HW_ALHOUR);
	alrm->time.tm_min = ioread32(priv->iobase + HW_ALMIN);
	alrm->time.tm_sec = ioread32(priv->iobase + HW_ALSEC);

	alrm->enabled = ioread32(priv->iobase + HW_AMR) ? 1 : 0;
	alrm->pending = ioread32(priv->iobase + HW_CIIR) ? 1 : 0;

	return rtc_valid_tm(&alrm->time);
	}

	static int asm9260_rtc_set_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);

	iowrite32(alrm->time.tm_year, priv->iobase + HW_ALYEAR);
	iowrite32(alrm->time.tm_mon, priv->iobase + HW_ALMON);
	iowrite32(alrm->time.tm_mday, priv->iobase + HW_ALDOM);
	iowrite32(alrm->time.tm_wday, priv->iobase + HW_ALDOW);
	iowrite32(alrm->time.tm_yday, priv->iobase + HW_ALDOY);
	iowrite32(alrm->time.tm_hour, priv->iobase + HW_ALHOUR);
	iowrite32(alrm->time.tm_min, priv->iobase + HW_ALMIN);
	iowrite32(alrm->time.tm_sec, priv->iobase + HW_ALSEC);

	iowrite32(alrm->enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);

	return 0;
	}

	static int asm9260_alarm_irq_enable(struct device *dev, unsigned int enabled)
	{
	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);

	iowrite32(enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
	return 0;
	}

	static const struct rtc_class_ops asm9260_rtc_ops = {
	.read_time = asm9260_rtc_read_time,
	.set_time = asm9260_rtc_set_time,
	.read_alarm = asm9260_rtc_read_alarm,
	.set_alarm = asm9260_rtc_set_alarm,
	.alarm_irq_enable = asm9260_alarm_irq_enable,
	};

	static int asm9260_rtc_probe(struct platform_device *pdev)
	{
	struct asm9260_rtc_priv *priv;
	struct device *dev = &pdev->dev;
	struct resource *res;
	int irq_alarm, ret;
	u32 ccr;

	priv = devm_kzalloc(dev, sizeof(struct asm9260_rtc_priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	priv->dev = &pdev->dev;
	platform_set_drvdata(pdev, priv);

	irq_alarm = platform_get_irq(pdev, 0);
	if (irq_alarm < 0) {
	dev_err(dev, "No alarm IRQ resource defined\n");
	return irq_alarm;
	}

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

	priv->clk = devm_clk_get(dev, "ahb");
	ret = clk_prepare_enable(priv->clk);
	if (ret) {
	dev_err(dev, "Failed to enable clk!\n");
	return ret;
	}

	ccr = ioread32(priv->iobase + HW_CCR);
	/* if dev is not enabled, reset it */
	if ((ccr & (BM_CLKEN \| BM_CTCRST)) != BM_CLKEN) {
	iowrite32(BM_CTCRST, priv->iobase + HW_CCR);
	ccr = 0;
	}

	iowrite32(BM_CLKEN \| ccr, priv->iobase + HW_CCR);
	iowrite32(0, priv->iobase + HW_CIIR);
	iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);

	priv->rtc = devm_rtc_device_register(dev, dev_name(dev),
	&asm9260_rtc_ops, THIS_MODULE);
	if (IS_ERR(priv->rtc)) {
	ret = PTR_ERR(priv->rtc);
	dev_err(dev, "Failed to register RTC device: %d\n", ret);
	goto err_return;
	}

	ret = devm_request_threaded_irq(dev, irq_alarm, NULL,
	asm9260_rtc_irq, IRQF_ONESHOT,
	dev_name(dev), priv);
	if (ret < 0) {
	dev_err(dev, "can't get irq %i, err %d\n",
	irq_alarm, ret);
	goto err_return;
	}

	return 0;

	err_return:
	clk_disable_unprepare(priv->clk);
	return ret;
	}

	static int asm9260_rtc_remove(struct platform_device *pdev)
	{
	struct asm9260_rtc_priv *priv = platform_get_drvdata(pdev);

	/* Disable alarm matching */
	iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);
	clk_disable_unprepare(priv->clk);
	return 0;
	}

	static const struct of_device_id asm9260_dt_ids[] = {
	{ .compatible = "alphascale,asm9260-rtc", },
	{}
	};
	MODULE_DEVICE_TABLE(of, asm9260_dt_ids);

	static struct platform_driver asm9260_rtc_driver = {
	.probe = asm9260_rtc_probe,
	.remove = asm9260_rtc_remove,
	.driver = {
	.name = "asm9260-rtc",
	.of_match_table = asm9260_dt_ids,
	},
	};

	module_platform_driver(asm9260_rtc_driver);

	MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
	MODULE_DESCRIPTION("Alphascale asm9260 SoC Realtime Clock Driver (RTC)");
	MODULE_LICENSE("GPL");