[Feature] add GA346 baseline version

Change-Id: Ic62933698569507dcf98240cdf5d9931ae34348f
diff --git a/src/kernel/linux/v4.19/drivers/rtc/rtc-mt6397.c b/src/kernel/linux/v4.19/drivers/rtc/rtc-mt6397.c
new file mode 100644
index 0000000..fa83cba
--- /dev/null
+++ b/src/kernel/linux/v4.19/drivers/rtc/rtc-mt6397.c
@@ -0,0 +1,732 @@
+/*
+* Copyright (c) 2014-2015 MediaTek Inc.
+* Author: Tianping.Fang <tianping.fang@mediatek.com>
+*
+* This program is free software; you can redistribute it and/or modify
+* it under the terms of the GNU General Public License version 2 as
+* published by the Free Software Foundation.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*/
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/irqdomain.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/io.h>
+#include <linux/mfd/mt6358/registers.h>
+#include <linux/mfd/mt6359/registers.h>
+#include <linux/mfd/mt6397/core.h>
+#include <linux/nvmem-provider.h>
+
+
+#define RTC_BBPU		0x0000
+#define RTC_BBPU_CBUSY		BIT(6)
+
+#define RTC_WRTGR_MT6358	0x3a
+#define RTC_WRTGR_MT6397	0x3c
+
+#define RTC_IRQ_STA		0x0002
+#define RTC_IRQ_STA_AL		BIT(0)
+#define RTC_IRQ_STA_LP		BIT(3)
+
+#define RTC_IRQ_EN		0x0004
+#define RTC_IRQ_EN_AL		BIT(0)
+#define RTC_IRQ_EN_ONESHOT	BIT(2)
+#define RTC_IRQ_EN_LP		BIT(3)
+#define RTC_IRQ_EN_ONESHOT_AL	(RTC_IRQ_EN_ONESHOT | RTC_IRQ_EN_AL)
+
+#define RTC_TC_SEC_MASK		0x3f
+#define RTC_TC_MIN_MASK		0x3f
+#define RTC_TC_HOU_MASK		0x1f
+#define RTC_TC_DOM_MASK		0x1f
+#define RTC_TC_DOW_MASK		0x7
+#define RTC_TC_MTH_MASK		0xf
+#define RTC_TC_YEA_MASK		0x7f
+
+#define RTC_AL_SEC_MASK		0x003f
+#define RTC_AL_MIN_MASK		0x003f
+#define RTC_AL_HOU_MASK		0x001f
+#define RTC_AL_DOM_MASK		0x001f
+#define RTC_AL_DOW_MASK		0x0007
+#define RTC_AL_MTH_MASK		0x000f
+#define RTC_AL_YEA_MASK		0x007f
+
+#define RTC_AL_MASK		0x0008
+#define RTC_AL_MASK_DOW		BIT(4)
+
+#define RTC_TC_SEC		0x000a
+/* Min, Hour, Dom... register offset to RTC_TC_SEC */
+#define RTC_OFFSET_SEC		0
+#define RTC_OFFSET_MIN		1
+#define RTC_OFFSET_HOUR		2
+#define RTC_OFFSET_DOM		3
+#define RTC_OFFSET_DOW		4
+#define RTC_OFFSET_MTH		5
+#define RTC_OFFSET_YEAR		6
+#define RTC_OFFSET_COUNT	7
+
+#define RTC_AL_SEC		0x0018
+#define RTC_AL_HOU		0x001c
+#define RTC_AL_MTH		0x0022
+
+#define RTC_AL_SEC_MASK		0x003f
+#define RTC_AL_MIN_MASK		0x003f
+#define RTC_AL_HOU_MASK		0x001f
+#define RTC_AL_DOM_MASK		0x001f
+#define RTC_AL_DOW_MASK		0x0007
+#define RTC_AL_MTH_MASK		0x000f
+#define RTC_AL_YEA_MASK		0x007f
+
+#define RTC_PDN2		0x002e
+#define RTC_PDN2_PWRON_ALARM	BIT(4)
+
+#define RTC_SPAR0		0x0030
+
+#define RTC_MIN_YEAR		1968
+#define RTC_BASE_YEAR		1900
+#define RTC_NUM_YEARS		128
+#define RTC_MIN_YEAR_OFFSET	(RTC_MIN_YEAR - RTC_BASE_YEAR)
+
+#define SPARE_REG_WIDTH		1
+
+enum mtk_rtc_spare_enum {
+	SPARE_AL_HOU,
+	SPARE_AL_MTH,
+	SPARE_SPAR0,
+	SPARE_RG_MAX,
+};
+
+enum rtc_eosc_cali_td {
+	EOSC_CALI_TD_01_SEC = 0x3,
+	EOSC_CALI_TD_02_SEC,
+	EOSC_CALI_TD_04_SEC,
+	EOSC_CALI_TD_08_SEC,
+	EOSC_CALI_TD_16_SEC,
+};
+
+enum cali_field_enum {
+	RTC_EOSC32_CK_PDN,
+	EOSC_CALI_TD,
+	CALI_FILED_MAX
+};
+
+struct mtk_rtc_compatible {
+	u32			wrtgr_addr;
+	const struct reg_field *spare_reg_fields;
+	const struct reg_field *cali_reg_fields;
+};
+
+struct mt6397_rtc {
+	struct device		*dev;
+	struct rtc_device	*rtc_dev;
+	struct mutex		lock;
+	struct regmap		*regmap;
+	int			irq;
+	u32			addr_base;
+	const struct mtk_rtc_compatible *dev_comp;
+	struct regmap_field	*spare[SPARE_RG_MAX];
+	struct regmap_field	*cali[CALI_FILED_MAX];
+	bool			cali_is_supported;
+};
+
+static const struct reg_field mt6358_cali_reg_fields[CALI_FILED_MAX] = {
+	[RTC_EOSC32_CK_PDN]	= REG_FIELD(MT6358_SCK_TOP_CKPDN_CON0, 2, 2),
+	[EOSC_CALI_TD]		= REG_FIELD(MT6358_EOSC_CALI_CON0, 5, 7),
+};
+
+static const struct reg_field mt6359_cali_reg_fields[CALI_FILED_MAX] = {
+	[RTC_EOSC32_CK_PDN]	= REG_FIELD(MT6359_SCK_TOP_CKPDN_CON0, 2, 2),
+	[EOSC_CALI_TD]		= REG_FIELD(MT6359_EOSC_CALI_CON0, 5, 7),
+};
+
+static const struct reg_field mtk_rtc_spare_reg_fields[SPARE_RG_MAX] = {
+	[SPARE_AL_HOU]		= REG_FIELD(RTC_AL_HOU, 8, 15),
+	[SPARE_AL_MTH]		= REG_FIELD(RTC_AL_MTH, 8, 15),
+	[SPARE_SPAR0]		= REG_FIELD(RTC_SPAR0, 0, 7),
+};
+
+static const struct mtk_rtc_compatible mt6359_rtc_compat = {
+	.wrtgr_addr		= RTC_WRTGR_MT6358,
+	.spare_reg_fields	= mtk_rtc_spare_reg_fields,
+	.cali_reg_fields	= mt6359_cali_reg_fields,
+};
+
+static const struct mtk_rtc_compatible mt6358_rtc_compat = {
+	.wrtgr_addr		= RTC_WRTGR_MT6358,
+	.spare_reg_fields	= mtk_rtc_spare_reg_fields,
+	.cali_reg_fields	= mt6358_cali_reg_fields,
+};
+
+static const struct mtk_rtc_compatible mt6397_rtc_compat = {
+	.wrtgr_addr = RTC_WRTGR_MT6397,
+};
+
+static const struct of_device_id mt6397_rtc_of_match[] = {
+	{ .compatible = "mediatek,mt6359-rtc",
+		.data = (void *)&mt6359_rtc_compat, },
+	{ .compatible = "mediatek,mt6358-rtc",
+		.data = (void *)&mt6358_rtc_compat, },
+	{ .compatible = "mediatek,mt6397-rtc",
+		.data = (void *)&mt6397_rtc_compat, },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mt6397_rtc_of_match);
+
+static int rtc_eosc_cali_td;
+module_param(rtc_eosc_cali_td, int, 0644);
+
+static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc)
+{
+	unsigned long timeout = jiffies + HZ;
+	int ret;
+	u32 data;
+
+	ret = regmap_write(rtc->regmap,
+			rtc->addr_base + rtc->dev_comp->wrtgr_addr, 1);
+	if (ret < 0)
+		return ret;
+
+	while (1) {
+		ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_BBPU,
+				  &data);
+		if (ret < 0)
+			break;
+		if (!(data & RTC_BBPU_CBUSY))
+			break;
+		if (time_after(jiffies, timeout)) {
+			ret = -ETIMEDOUT;
+			break;
+		}
+		cpu_relax();
+	}
+
+	return ret;
+}
+
+static int rtc_nvram_read(void *priv, unsigned int offset, void *val,
+							size_t bytes)
+{
+	struct mt6397_rtc *rtc = dev_get_drvdata(priv);
+	unsigned int ival;
+	int ret;
+	u8 *buf = val;
+
+	mutex_lock(&rtc->lock);
+
+	for (; bytes; bytes--) {
+		ret = regmap_field_read(rtc->spare[offset++], &ival);
+		if (ret)
+			goto out;
+		*buf++ = (u8)ival;
+	}
+out:
+	mutex_unlock(&rtc->lock);
+	return ret;
+}
+
+static int rtc_nvram_write(void *priv, unsigned int offset, void *val,
+							size_t bytes)
+{
+	struct mt6397_rtc *rtc = dev_get_drvdata(priv);
+	unsigned int ival;
+	int ret;
+	u8 *buf = val;
+
+	mutex_lock(&rtc->lock);
+
+	for (; bytes; bytes--) {
+		ival = *buf++;
+		ret = regmap_field_write(rtc->spare[offset++], ival);
+		if (ret)
+			goto out;
+	}
+	mtk_rtc_write_trigger(rtc);
+out:
+	mutex_unlock(&rtc->lock);
+	return ret;
+}
+
+static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data)
+{
+	struct mt6397_rtc *rtc = data;
+	u32 irqsta, irqen;
+	int ret;
+
+	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_STA, &irqsta);
+	if ((ret >= 0) && (irqsta & RTC_IRQ_STA_AL)) {
+		rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
+		irqen = irqsta & ~RTC_IRQ_EN_AL;
+		mutex_lock(&rtc->lock);
+		if (regmap_write(rtc->regmap, rtc->addr_base + RTC_IRQ_EN,
+				 irqen) == 0)
+			mtk_rtc_write_trigger(rtc);
+		mutex_unlock(&rtc->lock);
+
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static int __mtk_rtc_read_time(struct mt6397_rtc *rtc,
+			       struct rtc_time *tm, int *sec)
+{
+	int ret;
+	u16 data[RTC_OFFSET_COUNT];
+
+	mutex_lock(&rtc->lock);
+	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC,
+			       data, RTC_OFFSET_COUNT);
+	if (ret < 0)
+		goto exit;
+
+	tm->tm_sec = data[RTC_OFFSET_SEC] & RTC_TC_SEC_MASK;
+	tm->tm_min = data[RTC_OFFSET_MIN] & RTC_TC_MIN_MASK;
+	tm->tm_hour = data[RTC_OFFSET_HOUR] & RTC_TC_HOU_MASK;
+	tm->tm_mday = data[RTC_OFFSET_DOM] & RTC_TC_DOM_MASK;
+	tm->tm_mon = data[RTC_OFFSET_MTH] & RTC_TC_MTH_MASK;
+	tm->tm_year = data[RTC_OFFSET_YEAR] & RTC_TC_YEA_MASK;
+
+	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC, sec);
+	*sec &= RTC_TC_SEC_MASK;
+exit:
+	mutex_unlock(&rtc->lock);
+	return ret;
+}
+
+static int mtk_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	time64_t time;
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+	int days, sec, ret;
+
+	do {
+		ret = __mtk_rtc_read_time(rtc, tm, &sec);
+		if (ret < 0)
+			goto exit;
+	} while (sec < tm->tm_sec);
+
+	/* HW register use 7 bits to store year data, minus
+	 * RTC_MIN_YEAR_OFFSET before write year data to register, and plus
+	 * RTC_MIN_YEAR_OFFSET back after read year from register
+	 */
+	tm->tm_year += RTC_MIN_YEAR_OFFSET;
+
+	/* HW register start mon from one, but tm_mon start from zero. */
+	tm->tm_mon--;
+	time = rtc_tm_to_time64(tm);
+
+	/* rtc_tm_to_time64 covert Gregorian date to seconds since
+	 * 01-01-1970 00:00:00, and this date is Thursday.
+	 */
+	days = div_s64(time, 86400);
+	tm->tm_wday = (days + 4) % 7;
+
+exit:
+	return ret;
+}
+
+static int mtk_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+	int ret;
+	u16 data[RTC_OFFSET_COUNT];
+
+	if (tm->tm_year > 195) {
+		dev_err(rtc->dev, "%s: invalid year %04d > 2095\n",
+					__func__, tm->tm_year + RTC_BASE_YEAR);
+		return -EINVAL;
+	}
+
+	tm->tm_year -= RTC_MIN_YEAR_OFFSET;
+	tm->tm_mon++;
+
+	data[RTC_OFFSET_SEC] = tm->tm_sec;
+	data[RTC_OFFSET_MIN] = tm->tm_min;
+	data[RTC_OFFSET_HOUR] = tm->tm_hour;
+	data[RTC_OFFSET_DOM] = tm->tm_mday;
+	data[RTC_OFFSET_MTH] = tm->tm_mon;
+	data[RTC_OFFSET_YEAR] = tm->tm_year;
+
+	mutex_lock(&rtc->lock);
+	ret = regmap_bulk_write(rtc->regmap, rtc->addr_base + RTC_TC_SEC,
+				data, RTC_OFFSET_COUNT);
+	if (ret < 0)
+		goto exit;
+
+	/* Time register write to hardware after call trigger function */
+	ret = mtk_rtc_write_trigger(rtc);
+
+exit:
+	mutex_unlock(&rtc->lock);
+	return ret;
+}
+
+static int mtk_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	struct rtc_time *tm = &alm->time;
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+	u32 irqen, pdn2;
+	int ret;
+	u16 data[RTC_OFFSET_COUNT];
+
+	mutex_lock(&rtc->lock);
+	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_EN, &irqen);
+	if (ret < 0)
+		goto err_exit;
+	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_PDN2, &pdn2);
+	if (ret < 0)
+		goto err_exit;
+
+	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
+			       data, RTC_OFFSET_COUNT);
+	if (ret < 0)
+		goto err_exit;
+
+	alm->enabled = !!(irqen & RTC_IRQ_EN_AL);
+	alm->pending = !!(pdn2 & RTC_PDN2_PWRON_ALARM);
+	mutex_unlock(&rtc->lock);
+
+	tm->tm_sec = data[RTC_OFFSET_SEC] & RTC_AL_SEC_MASK;
+	tm->tm_min = data[RTC_OFFSET_MIN] & RTC_AL_MIN_MASK;
+	tm->tm_hour = data[RTC_OFFSET_HOUR] & RTC_AL_HOU_MASK;
+	tm->tm_mday = data[RTC_OFFSET_DOM] & RTC_AL_DOM_MASK;
+	tm->tm_mon = data[RTC_OFFSET_MTH] & RTC_AL_MTH_MASK;
+	tm->tm_year = data[RTC_OFFSET_YEAR] & RTC_AL_YEA_MASK;
+
+	tm->tm_year += RTC_MIN_YEAR_OFFSET;
+	tm->tm_mon--;
+
+	return 0;
+err_exit:
+	mutex_unlock(&rtc->lock);
+	return ret;
+}
+
+static int mtk_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	struct rtc_time *tm = &alm->time;
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+	int ret;
+	u16 data[RTC_OFFSET_COUNT];
+
+	if (tm->tm_year > 195) {
+		dev_err(rtc->dev, "%s: invalid year %04d > 2095\n",
+				__func__, tm->tm_year + RTC_BASE_YEAR);
+		return -EINVAL;
+	}
+
+	tm->tm_year -= RTC_MIN_YEAR_OFFSET;
+	tm->tm_mon++;
+
+	mutex_lock(&rtc->lock);
+	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
+			       data, RTC_OFFSET_COUNT);
+	if (ret < 0)
+		goto exit;
+
+	data[RTC_OFFSET_SEC] = ((data[RTC_OFFSET_SEC] & ~(RTC_AL_SEC_MASK)) |
+				(tm->tm_sec & RTC_AL_SEC_MASK));
+	data[RTC_OFFSET_MIN] = ((data[RTC_OFFSET_MIN] & ~(RTC_AL_MIN_MASK)) |
+				(tm->tm_min & RTC_AL_MIN_MASK));
+	data[RTC_OFFSET_HOUR] = ((data[RTC_OFFSET_HOUR] & ~(RTC_AL_HOU_MASK)) |
+				(tm->tm_hour & RTC_AL_HOU_MASK));
+	data[RTC_OFFSET_DOM] = ((data[RTC_OFFSET_DOM] & ~(RTC_AL_DOM_MASK)) |
+				(tm->tm_mday & RTC_AL_DOM_MASK));
+	data[RTC_OFFSET_MTH] = ((data[RTC_OFFSET_MTH] & ~(RTC_AL_MTH_MASK)) |
+				(tm->tm_mon & RTC_AL_MTH_MASK));
+	data[RTC_OFFSET_YEAR] = ((data[RTC_OFFSET_YEAR] & ~(RTC_AL_YEA_MASK)) |
+				(tm->tm_year & RTC_AL_YEA_MASK));
+
+	if (alm->enabled) {
+		ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
+			       data, RTC_OFFSET_COUNT);
+		if (ret < 0)
+			goto exit;
+		data[RTC_OFFSET_SEC] =
+			((data[RTC_OFFSET_SEC] & ~(RTC_AL_SEC_MASK)) |
+					(tm->tm_sec & RTC_AL_SEC_MASK));
+		data[RTC_OFFSET_MIN] =
+			((data[RTC_OFFSET_MIN] & ~(RTC_AL_MIN_MASK)) |
+					(tm->tm_min & RTC_AL_MIN_MASK));
+		data[RTC_OFFSET_HOUR] =
+			((data[RTC_OFFSET_HOUR] & ~(RTC_AL_HOU_MASK)) |
+					(tm->tm_hour & RTC_AL_HOU_MASK));
+		data[RTC_OFFSET_DOM] =
+			((data[RTC_OFFSET_DOM] & ~(RTC_AL_DOM_MASK)) |
+					(tm->tm_mday & RTC_AL_DOM_MASK));
+		data[RTC_OFFSET_MTH] =
+			((data[RTC_OFFSET_MTH] & ~(RTC_AL_MTH_MASK)) |
+					(tm->tm_mon & RTC_AL_MTH_MASK));
+		data[RTC_OFFSET_YEAR] =
+			((data[RTC_OFFSET_YEAR] & ~(RTC_AL_YEA_MASK)) |
+				(tm->tm_year & RTC_AL_YEA_MASK));
+		ret = regmap_bulk_write(rtc->regmap,
+					rtc->addr_base + RTC_AL_SEC,
+					data, RTC_OFFSET_COUNT);
+		if (ret < 0)
+			goto exit;
+		ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_AL_MASK,
+				   RTC_AL_MASK_DOW);
+		if (ret < 0)
+			goto exit;
+		ret = regmap_update_bits(rtc->regmap,
+					 rtc->addr_base + RTC_IRQ_EN,
+					 RTC_IRQ_EN_ONESHOT_AL,
+					 RTC_IRQ_EN_ONESHOT_AL);
+		if (ret < 0)
+			goto exit;
+	} else {
+		ret = regmap_update_bits(rtc->regmap,
+					 rtc->addr_base + RTC_IRQ_EN,
+					 RTC_IRQ_EN_ONESHOT_AL, 0);
+		if (ret < 0)
+			goto exit;
+	}
+
+	/* All alarm time register write to hardware after calling
+	 * mtk_rtc_write_trigger. This can avoid race condition if alarm
+	 * occur happen during writing alarm time register.
+	 */
+	ret = mtk_rtc_write_trigger(rtc);
+exit:
+	mutex_unlock(&rtc->lock);
+	return ret;
+}
+
+static const struct rtc_class_ops mtk_rtc_ops = {
+	.read_time  = mtk_rtc_read_time,
+	.set_time   = mtk_rtc_set_time,
+	.read_alarm = mtk_rtc_read_alarm,
+	.set_alarm  = mtk_rtc_set_alarm,
+};
+
+static void mtk_rtc_enable_k_eosc(struct device *dev)
+{
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+	u32 td;
+
+	if (!rtc->cali_is_supported)
+		return;
+
+	/* Truning on eosc cali mode clock */
+	regmap_field_write(rtc->cali[RTC_EOSC32_CK_PDN], 0);
+
+	if (rtc_eosc_cali_td) {
+		dev_notice(dev, "%s: rtc_eosc_cali_td = %d\n",
+				__func__, rtc_eosc_cali_td);
+		switch (rtc_eosc_cali_td) {
+		case 1:
+			td = EOSC_CALI_TD_01_SEC;
+			break;
+		case 2:
+			td = EOSC_CALI_TD_02_SEC;
+			break;
+		case 4:
+			td = EOSC_CALI_TD_04_SEC;
+			break;
+		case 16:
+			td = EOSC_CALI_TD_16_SEC;
+			break;
+		default:
+			td = EOSC_CALI_TD_08_SEC;
+			break;
+		}
+		regmap_field_write(rtc->cali[EOSC_CALI_TD], td);
+	}
+}
+
+static void mtk_rtc_shutdown(struct platform_device *pdev)
+{
+	mtk_rtc_enable_k_eosc(&pdev->dev);
+}
+
+static int mtk_rtc_config_eosc_cali(struct device *dev)
+{
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < CALI_FILED_MAX; i++) {
+		rtc->cali[i] = devm_regmap_field_alloc(dev, rtc->regmap,
+					rtc->dev_comp->cali_reg_fields[i]);
+		if (IS_ERR(rtc->cali[i])) {
+			dev_err(rtc->dev, "cali regmap field[%d] err= %ld\n",
+						i, PTR_ERR(rtc->cali[i]));
+			return PTR_ERR(rtc->cali[i]);
+		}
+	}
+	rtc->cali_is_supported = true;
+
+	return 0;
+}
+
+static int mtk_rtc_set_spare(struct device *dev)
+{
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+	struct reg_field tmp[SPARE_RG_MAX];
+	int i, ret;
+	struct nvmem_config nvmem_cfg = {
+		.name = "mtk_rtc_nvmem",
+		.word_size = SPARE_REG_WIDTH,
+		.stride = 1,
+		.size = SPARE_RG_MAX * SPARE_REG_WIDTH,
+		.reg_read = rtc_nvram_read,
+		.reg_write = rtc_nvram_write,
+		.priv = dev,
+	};
+
+	memcpy(tmp, rtc->dev_comp->spare_reg_fields, sizeof(tmp));
+
+	for (i = 0; i < SPARE_RG_MAX; i++) {
+		tmp[i].reg += rtc->addr_base;
+		rtc->spare[i] = devm_regmap_field_alloc(rtc->dev,
+							rtc->regmap,
+							tmp[i]);
+		if (IS_ERR(rtc->spare[i])) {
+			dev_err(rtc->dev, "spare regmap field[%d] err= %ld\n",
+						i, PTR_ERR(rtc->spare[i]));
+			return PTR_ERR(rtc->spare[i]);
+		}
+	}
+
+	ret = rtc_nvmem_register(rtc->rtc_dev, &nvmem_cfg);
+	if (ret)
+		dev_err(rtc->dev, "nvmem register failed\n");
+
+	return ret;
+}
+
+static int mtk_rtc_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
+	struct mt6397_rtc *rtc;
+	const struct of_device_id *of_id;
+	int ret;
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(struct mt6397_rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rtc->addr_base = res->start;
+
+	of_id = of_match_device(mt6397_rtc_of_match, &pdev->dev);
+	if (!of_id) {
+		dev_err(&pdev->dev, "Failed to probe of_node\n");
+		return -EINVAL;
+	}
+	rtc->dev_comp = of_id->data;
+
+	rtc->irq = platform_get_irq(pdev, 0);
+	if (rtc->irq < 0)
+		return rtc->irq;
+
+	rtc->regmap = mt6397_chip->regmap;
+	rtc->dev = &pdev->dev;
+	mutex_init(&rtc->lock);
+
+	platform_set_drvdata(pdev, rtc);
+
+	rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev);
+	if (IS_ERR(rtc->rtc_dev))
+		return PTR_ERR(rtc->rtc_dev);
+
+	ret = request_threaded_irq(rtc->irq, NULL,
+				   mtk_rtc_irq_handler_thread,
+				   IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
+				   "mt6397-rtc", rtc);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
+			rtc->irq, ret);
+		goto out_dispose_irq;
+	}
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	rtc->rtc_dev->ops = &mtk_rtc_ops;
+
+	ret = rtc_register_device(rtc->rtc_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "register rtc device failed\n");
+		goto out_free_irq;
+	}
+
+	if (rtc->dev_comp->spare_reg_fields)
+		if (mtk_rtc_set_spare(&pdev->dev))
+			dev_err(&pdev->dev, "spare is not supported\n");
+
+	if (rtc->dev_comp->cali_reg_fields)
+		if (mtk_rtc_config_eosc_cali(&pdev->dev))
+			dev_err(&pdev->dev, "config eosc cali failed\n");
+
+	return 0;
+
+out_free_irq:
+	free_irq(rtc->irq, rtc->rtc_dev);
+out_dispose_irq:
+	irq_dispose_mapping(rtc->irq);
+	return ret;
+}
+
+static int mtk_rtc_remove(struct platform_device *pdev)
+{
+	struct mt6397_rtc *rtc = platform_get_drvdata(pdev);
+
+	free_irq(rtc->irq, rtc->rtc_dev);
+	irq_dispose_mapping(rtc->irq);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mt6397_rtc_suspend(struct device *dev)
+{
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(rtc->irq);
+
+	return 0;
+}
+
+static int mt6397_rtc_resume(struct device *dev)
+{
+	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(rtc->irq);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(mt6397_pm_ops, mt6397_rtc_suspend,
+			mt6397_rtc_resume);
+
+static struct platform_driver mtk_rtc_driver = {
+	.driver = {
+		.name = "mt6397-rtc",
+		.of_match_table = mt6397_rtc_of_match,
+		.pm = &mt6397_pm_ops,
+	},
+	.probe	= mtk_rtc_probe,
+	.remove = mtk_rtc_remove,
+	.shutdown = mtk_rtc_shutdown,
+};
+
+module_platform_driver(mtk_rtc_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Tianping Fang <tianping.fang@mediatek.com>");
+MODULE_DESCRIPTION("RTC Driver for MediaTek MT6397 PMIC");