drivers/rtc/rtc-nct3018y.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2022 Nuvoton Technology Corporation

 #include <linux/bcd.h>
 #include <linux/clk-provider.h>
 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/rtc.h>
 #include <linux/slab.h>

 #define NCT3018Y_REG_SC		0x00 /* seconds */
 #define NCT3018Y_REG_SCA	0x01 /* alarm */
 #define NCT3018Y_REG_MN		0x02
 #define NCT3018Y_REG_MNA	0x03 /* alarm */
 #define NCT3018Y_REG_HR		0x04
 #define NCT3018Y_REG_HRA	0x05 /* alarm */
 #define NCT3018Y_REG_DW		0x06
 #define NCT3018Y_REG_DM		0x07
 #define NCT3018Y_REG_MO		0x08
 #define NCT3018Y_REG_YR		0x09
 #define NCT3018Y_REG_CTRL	0x0A /* timer control */
 #define NCT3018Y_REG_ST		0x0B /* status */
 #define NCT3018Y_REG_CLKO	0x0C /* clock out */

 #define NCT3018Y_BIT_AF		BIT(7)
 #define NCT3018Y_BIT_ST		BIT(7)
 #define NCT3018Y_BIT_DM		BIT(6)
 #define NCT3018Y_BIT_HF		BIT(5)
 #define NCT3018Y_BIT_DSM	BIT(4)
 #define NCT3018Y_BIT_AIE	BIT(3)
 #define NCT3018Y_BIT_OFIE	BIT(2)
 #define NCT3018Y_BIT_CIE	BIT(1)
 #define NCT3018Y_BIT_TWO	BIT(0)

 #define NCT3018Y_REG_BAT_MASK		0x07
 #define NCT3018Y_REG_CLKO_F_MASK	0x03 /* frequenc mask */
 #define NCT3018Y_REG_CLKO_CKE		0x80 /* clock out enabled */

 struct nct3018y {
 	struct rtc_device *rtc;
 	struct i2c_client *client;
 #ifdef CONFIG_COMMON_CLK
 	struct clk_hw clkout_hw;
 #endif
 };

 static int nct3018y_set_alarm_mode(struct i2c_client *client, bool on)
 {
 	int err, flags;

 	dev_dbg(&client->dev, "%s:on:%d\n", __func__, on);

 	flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
 	if (flags < 0) {
 		dev_dbg(&client->dev,
 			"Failed to read NCT3018Y_REG_CTRL\n");
 		return flags;
 	}

 	if (on)
 		flags |= NCT3018Y_BIT_AIE;
 	else
 		flags &= ~NCT3018Y_BIT_AIE;

 	flags |= NCT3018Y_BIT_CIE;
 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
 		return err;
 	}

 	flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
 	if (flags < 0) {
 		dev_dbg(&client->dev,
 			"Failed to read NCT3018Y_REG_ST\n");
 		return flags;
 	}

 	flags &= ~(NCT3018Y_BIT_AF);
 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_ST\n");
 		return err;
 	}

 	return 0;
 }

 static int nct3018y_get_alarm_mode(struct i2c_client *client, unsigned char *alarm_enable,
 				   unsigned char *alarm_flag)
 {
 	int flags;

 	if (alarm_enable) {
 		dev_dbg(&client->dev, "%s:NCT3018Y_REG_CTRL\n", __func__);
 		flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
 		if (flags < 0)
 			return flags;
 		*alarm_enable = flags & NCT3018Y_BIT_AIE;
 	}

 	if (alarm_flag) {
 		dev_dbg(&client->dev, "%s:NCT3018Y_REG_ST\n", __func__);
 		flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
 		if (flags < 0)
 			return flags;
 		*alarm_flag = flags & NCT3018Y_BIT_AF;
 	}

 	dev_dbg(&client->dev, "%s:alarm_enable:%x alarm_flag:%x\n",
 		__func__, *alarm_enable, *alarm_flag);

 	return 0;
 }

 static irqreturn_t nct3018y_irq(int irq, void *dev_id)
 {
 	struct nct3018y *nct3018y = i2c_get_clientdata(dev_id);
 	struct i2c_client *client = nct3018y->client;
 	int err;
 	unsigned char alarm_flag;
 	unsigned char alarm_enable;

 	dev_dbg(&client->dev, "%s:irq:%d\n", __func__, irq);
 	err = nct3018y_get_alarm_mode(nct3018y->client, &alarm_enable, &alarm_flag);
 	if (err)
 		return IRQ_NONE;

 	if (alarm_flag) {
 		dev_dbg(&client->dev, "%s:alarm flag:%x\n",
 			__func__, alarm_flag);
 		rtc_update_irq(nct3018y->rtc, 1, RTC_IRQF | RTC_AF);
 		nct3018y_set_alarm_mode(nct3018y->client, 0);
 		dev_dbg(&client->dev, "%s:IRQ_HANDLED\n", __func__);
 		return IRQ_HANDLED;
 	}

 	return IRQ_NONE;
 }

 /*
  * In the routines that deal directly with the nct3018y hardware, we use
  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  */
 static int nct3018y_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned char buf[10];
 	int err;

 	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_ST, 1, buf);
 	if (err < 0)
 		return err;

 	if (!buf[0]) {
 		dev_dbg(&client->dev, " voltage <=1.7, date/time is not reliable.\n");
 		return -EINVAL;
 	}

 	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SC, sizeof(buf), buf);
 	if (err < 0)
 		return err;

 	tm->tm_sec = bcd2bin(buf[0] & 0x7F);
 	tm->tm_min = bcd2bin(buf[2] & 0x7F);
 	tm->tm_hour = bcd2bin(buf[4] & 0x3F);
 	tm->tm_wday = buf[6] & 0x07;
 	tm->tm_mday = bcd2bin(buf[7] & 0x3F);
 	tm->tm_mon = bcd2bin(buf[8] & 0x1F) - 1;
 	tm->tm_year = bcd2bin(buf[9]) + 100;

 	return 0;
 }

 static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned char buf[4] = {0};
 	int err;

 	buf[0] = bin2bcd(tm->tm_sec);
 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SC, buf[0]);
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_SC\n");
 		return err;
 	}

 	buf[0] = bin2bcd(tm->tm_min);
 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MN, buf[0]);
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_MN\n");
 		return err;
 	}

 	buf[0] = bin2bcd(tm->tm_hour);
 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HR, buf[0]);
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_HR\n");
 		return err;
 	}

 	buf[0] = tm->tm_wday & 0x07;
 	buf[1] = bin2bcd(tm->tm_mday);
 	buf[2] = bin2bcd(tm->tm_mon + 1);
 	buf[3] = bin2bcd(tm->tm_year - 100);
 	err = i2c_smbus_write_i2c_block_data(client, NCT3018Y_REG_DW,
 					     sizeof(buf), buf);
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write for day and mon and year\n");
 		return -EIO;
 	}

 	return err;
 }

 static int nct3018y_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned char buf[5];
 	int err;

 	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SCA,
 					    sizeof(buf), buf);
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to read date\n");
 		return -EIO;
 	}

 	dev_dbg(&client->dev, "%s: raw data is sec=%02x, min=%02x hr=%02x\n",
 		__func__, buf[0], buf[2], buf[4]);

 	tm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
 	tm->time.tm_min = bcd2bin(buf[2] & 0x7F);
 	tm->time.tm_hour = bcd2bin(buf[4] & 0x3F);

 	err = nct3018y_get_alarm_mode(client, &tm->enabled, &tm->pending);
 	if (err < 0)
 		return err;

 	dev_dbg(&client->dev, "%s:s=%d m=%d, hr=%d, enabled=%d, pending=%d\n",
 		__func__, tm->time.tm_sec, tm->time.tm_min,
 		tm->time.tm_hour, tm->enabled, tm->pending);

 	return 0;
 }

 static int nct3018y_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	int err;

 	dev_dbg(dev, "%s, sec=%d, min=%d hour=%d tm->enabled:%d\n",
 		__func__, tm->time.tm_sec, tm->time.tm_min, tm->time.tm_hour,
 		tm->enabled);

 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SCA, bin2bcd(tm->time.tm_sec));
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_SCA\n");
 		return err;
 	}

 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MNA, bin2bcd(tm->time.tm_min));
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_MNA\n");
 		return err;
 	}

 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HRA, bin2bcd(tm->time.tm_hour));
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_HRA\n");
 		return err;
 	}

 	return nct3018y_set_alarm_mode(client, tm->enabled);
 }

 static int nct3018y_irq_enable(struct device *dev, unsigned int enabled)
 {
 	dev_dbg(dev, "%s: alarm enable=%d\n", __func__, enabled);

 	return nct3018y_set_alarm_mode(to_i2c_client(dev), enabled);
 }

 static int nct3018y_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	int status, flags = 0;

 	switch (cmd) {
 	case RTC_VL_READ:
 		status = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
 		if (status < 0)
 			return status;

 		if (!(status & NCT3018Y_REG_BAT_MASK))
 			flags |= RTC_VL_DATA_INVALID;

 		return put_user(flags, (unsigned int __user *)arg);

 	default:
 		return -ENOIOCTLCMD;
 	}
 }

 #ifdef CONFIG_COMMON_CLK
 /*
  * Handling of the clkout
  */

 #define clkout_hw_to_nct3018y(_hw) container_of(_hw, struct nct3018y, clkout_hw)

 static const int clkout_rates[] = {
 	32768,
 	1024,
 	32,
 	1,
 };

 static unsigned long nct3018y_clkout_recalc_rate(struct clk_hw *hw,
 						 unsigned long parent_rate)
 {
 	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
 	struct i2c_client *client = nct3018y->client;
 	int flags;

 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
 	if (flags < 0)
 		return 0;

 	flags &= NCT3018Y_REG_CLKO_F_MASK;
 	return clkout_rates[flags];
 }

 static long nct3018y_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
 				       unsigned long *prate)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
 		if (clkout_rates[i] <= rate)
 			return clkout_rates[i];

 	return 0;
 }

 static int nct3018y_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
 				    unsigned long parent_rate)
 {
 	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
 	struct i2c_client *client = nct3018y->client;
 	int i, flags;

 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
 	if (flags < 0)
 		return flags;

 	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
 		if (clkout_rates[i] == rate) {
 			flags &= ~NCT3018Y_REG_CLKO_F_MASK;
 			flags |= i;
 			return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
 		}

 	return -EINVAL;
 }

 static int nct3018y_clkout_control(struct clk_hw *hw, bool enable)
 {
 	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
 	struct i2c_client *client = nct3018y->client;
 	int flags;

 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
 	if (flags < 0)
 		return flags;

 	if (enable)
 		flags |= NCT3018Y_REG_CLKO_CKE;
 	else
 		flags &= ~NCT3018Y_REG_CLKO_CKE;

 	return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
 }

 static int nct3018y_clkout_prepare(struct clk_hw *hw)
 {
 	return nct3018y_clkout_control(hw, 1);
 }

 static void nct3018y_clkout_unprepare(struct clk_hw *hw)
 {
 	nct3018y_clkout_control(hw, 0);
 }

 static int nct3018y_clkout_is_prepared(struct clk_hw *hw)
 {
 	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
 	struct i2c_client *client = nct3018y->client;
 	int flags;

 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
 	if (flags < 0)
 		return flags;

 	return flags & NCT3018Y_REG_CLKO_CKE;
 }

 static const struct clk_ops nct3018y_clkout_ops = {
 	.prepare = nct3018y_clkout_prepare,
 	.unprepare = nct3018y_clkout_unprepare,
 	.is_prepared = nct3018y_clkout_is_prepared,
 	.recalc_rate = nct3018y_clkout_recalc_rate,
 	.round_rate = nct3018y_clkout_round_rate,
 	.set_rate = nct3018y_clkout_set_rate,
 };

 static struct clk *nct3018y_clkout_register_clk(struct nct3018y *nct3018y)
 {
 	struct i2c_client *client = nct3018y->client;
 	struct device_node *node = client->dev.of_node;
 	struct clk *clk;
 	struct clk_init_data init;

 	init.name = "nct3018y-clkout";
 	init.ops = &nct3018y_clkout_ops;
 	init.flags = 0;
 	init.parent_names = NULL;
 	init.num_parents = 0;
 	nct3018y->clkout_hw.init = &init;

 	/* optional override of the clockname */
 	of_property_read_string(node, "clock-output-names", &init.name);

 	/* register the clock */
 	clk = devm_clk_register(&client->dev, &nct3018y->clkout_hw);

 	if (!IS_ERR(clk))
 		of_clk_add_provider(node, of_clk_src_simple_get, clk);

 	return clk;
 }
 #endif

 static const struct rtc_class_ops nct3018y_rtc_ops = {
 	.read_time	= nct3018y_rtc_read_time,
 	.set_time	= nct3018y_rtc_set_time,
 	.read_alarm	= nct3018y_rtc_read_alarm,
 	.set_alarm	= nct3018y_rtc_set_alarm,
 	.alarm_irq_enable = nct3018y_irq_enable,
 	.ioctl		= nct3018y_ioctl,
 };

 static int nct3018y_probe(struct i2c_client *client)
 {
 	struct nct3018y *nct3018y;
 	int err, flags;

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 				     I2C_FUNC_SMBUS_BYTE |
 				     I2C_FUNC_SMBUS_BLOCK_DATA))
 		return -ENODEV;

 	nct3018y = devm_kzalloc(&client->dev, sizeof(struct nct3018y),
 				GFP_KERNEL);
 	if (!nct3018y)
 		return -ENOMEM;

 	i2c_set_clientdata(client, nct3018y);
 	nct3018y->client = client;
 	device_set_wakeup_capable(&client->dev, 1);

 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
 	if (flags < 0) {
 		dev_dbg(&client->dev, "%s: read error\n", __func__);
 		return flags;
 	} else if (flags & NCT3018Y_BIT_TWO) {
 		dev_dbg(&client->dev, "%s: NCT3018Y_BIT_TWO is set\n", __func__);
 	}

 	flags = NCT3018Y_BIT_TWO;
 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
 	if (err < 0) {
 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
 		return err;
 	}

 	flags = 0;
 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
 	if (err < 0) {
 		dev_dbg(&client->dev, "%s: write error\n", __func__);
 		return err;
 	}

 	nct3018y->rtc = devm_rtc_allocate_device(&client->dev);
 	if (IS_ERR(nct3018y->rtc))
 		return PTR_ERR(nct3018y->rtc);

 	nct3018y->rtc->ops = &nct3018y_rtc_ops;
 	nct3018y->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	nct3018y->rtc->range_max = RTC_TIMESTAMP_END_2099;

 	if (client->irq > 0) {
 		err = devm_request_threaded_irq(&client->dev, client->irq,
 						NULL, nct3018y_irq,
 						IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
 						"nct3018y", client);
 		if (err) {
 			dev_dbg(&client->dev, "unable to request IRQ %d\n", client->irq);
 			return err;
 		}
 	} else {
 		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, nct3018y->rtc->features);
 		clear_bit(RTC_FEATURE_ALARM, nct3018y->rtc->features);
 	}

 #ifdef CONFIG_COMMON_CLK
 	/* register clk in common clk framework */
 	nct3018y_clkout_register_clk(nct3018y);
 #endif

 	return devm_rtc_register_device(nct3018y->rtc);
 }

 static const struct i2c_device_id nct3018y_id[] = {
 	{ "nct3018y", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, nct3018y_id);

 static const struct of_device_id nct3018y_of_match[] = {
 	{ .compatible = "nuvoton,nct3018y" },
 	{}
 };
 MODULE_DEVICE_TABLE(of, nct3018y_of_match);

 static struct i2c_driver nct3018y_driver = {
 	.driver		= {
 		.name	= "rtc-nct3018y",
 		.of_match_table = nct3018y_of_match,
 	},
 	.probe		= nct3018y_probe,
 	.id_table	= nct3018y_id,
 };

 module_i2c_driver(nct3018y_driver);

 MODULE_AUTHOR("Medad CChien <ctcchien@nuvoton.com>");
 MODULE_AUTHOR("Mia Lin <mimi05633@gmail.com>");
 MODULE_DESCRIPTION("Nuvoton NCT3018Y RTC driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	// Copyright (c) 2022 Nuvoton Technology Corporation

	#include <linux/bcd.h>
	#include <linux/clk-provider.h>
	#include <linux/err.h>
	#include <linux/i2c.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/rtc.h>
	#include <linux/slab.h>

	#define NCT3018Y_REG_SC 0x00 /* seconds */
	#define NCT3018Y_REG_SCA 0x01 /* alarm */
	#define NCT3018Y_REG_MN 0x02
	#define NCT3018Y_REG_MNA 0x03 /* alarm */
	#define NCT3018Y_REG_HR 0x04
	#define NCT3018Y_REG_HRA 0x05 /* alarm */
	#define NCT3018Y_REG_DW 0x06
	#define NCT3018Y_REG_DM 0x07
	#define NCT3018Y_REG_MO 0x08
	#define NCT3018Y_REG_YR 0x09
	#define NCT3018Y_REG_CTRL 0x0A /* timer control */
	#define NCT3018Y_REG_ST 0x0B /* status */
	#define NCT3018Y_REG_CLKO 0x0C /* clock out */

	#define NCT3018Y_BIT_AF BIT(7)
	#define NCT3018Y_BIT_ST BIT(7)
	#define NCT3018Y_BIT_DM BIT(6)
	#define NCT3018Y_BIT_HF BIT(5)
	#define NCT3018Y_BIT_DSM BIT(4)
	#define NCT3018Y_BIT_AIE BIT(3)
	#define NCT3018Y_BIT_OFIE BIT(2)
	#define NCT3018Y_BIT_CIE BIT(1)
	#define NCT3018Y_BIT_TWO BIT(0)

	#define NCT3018Y_REG_BAT_MASK 0x07
	#define NCT3018Y_REG_CLKO_F_MASK 0x03 /* frequenc mask */
	#define NCT3018Y_REG_CLKO_CKE 0x80 /* clock out enabled */

	struct nct3018y {
	struct rtc_device *rtc;
	struct i2c_client *client;
	#ifdef CONFIG_COMMON_CLK
	struct clk_hw clkout_hw;
	#endif
	};

	static int nct3018y_set_alarm_mode(struct i2c_client *client, bool on)
	{
	int err, flags;

	dev_dbg(&client->dev, "%s:on:%d\n", __func__, on);

	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
	if (flags < 0) {
	dev_dbg(&client->dev,
	"Failed to read NCT3018Y_REG_CTRL\n");
	return flags;
	}

	if (on)
	flags \|= NCT3018Y_BIT_AIE;
	else
	flags &= ~NCT3018Y_BIT_AIE;

	flags \|= NCT3018Y_BIT_CIE;
	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
	return err;
	}

	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
	if (flags < 0) {
	dev_dbg(&client->dev,
	"Failed to read NCT3018Y_REG_ST\n");
	return flags;
	}

	flags &= ~(NCT3018Y_BIT_AF);
	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_ST\n");
	return err;
	}

	return 0;
	}

	static int nct3018y_get_alarm_mode(struct i2c_client client, unsigned char alarm_enable,
	unsigned char *alarm_flag)
	{
	int flags;

	if (alarm_enable) {
	dev_dbg(&client->dev, "%s:NCT3018Y_REG_CTRL\n", __func__);
	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
	if (flags < 0)
	return flags;
	*alarm_enable = flags & NCT3018Y_BIT_AIE;
	}

	if (alarm_flag) {
	dev_dbg(&client->dev, "%s:NCT3018Y_REG_ST\n", __func__);
	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
	if (flags < 0)
	return flags;
	*alarm_flag = flags & NCT3018Y_BIT_AF;
	}

	dev_dbg(&client->dev, "%s:alarm_enable:%x alarm_flag:%x\n",
	__func__, alarm_enable, alarm_flag);

	return 0;
	}

	static irqreturn_t nct3018y_irq(int irq, void *dev_id)
	{
	struct nct3018y *nct3018y = i2c_get_clientdata(dev_id);
	struct i2c_client *client = nct3018y->client;
	int err;
	unsigned char alarm_flag;
	unsigned char alarm_enable;

	dev_dbg(&client->dev, "%s:irq:%d\n", __func__, irq);
	err = nct3018y_get_alarm_mode(nct3018y->client, &alarm_enable, &alarm_flag);
	if (err)
	return IRQ_NONE;

	if (alarm_flag) {
	dev_dbg(&client->dev, "%s:alarm flag:%x\n",
	__func__, alarm_flag);
	rtc_update_irq(nct3018y->rtc, 1, RTC_IRQF \| RTC_AF);
	nct3018y_set_alarm_mode(nct3018y->client, 0);
	dev_dbg(&client->dev, "%s:IRQ_HANDLED\n", __func__);
	return IRQ_HANDLED;
	}

	return IRQ_NONE;
	}

	/*
	* In the routines that deal directly with the nct3018y hardware, we use
	* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
	*/
	static int nct3018y_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned char buf[10];
	int err;

	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_ST, 1, buf);
	if (err < 0)
	return err;

	if (!buf[0]) {
	dev_dbg(&client->dev, " voltage <=1.7, date/time is not reliable.\n");
	return -EINVAL;
	}

	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SC, sizeof(buf), buf);
	if (err < 0)
	return err;

	tm->tm_sec = bcd2bin(buf[0] & 0x7F);
	tm->tm_min = bcd2bin(buf[2] & 0x7F);
	tm->tm_hour = bcd2bin(buf[4] & 0x3F);
	tm->tm_wday = buf[6] & 0x07;
	tm->tm_mday = bcd2bin(buf[7] & 0x3F);
	tm->tm_mon = bcd2bin(buf[8] & 0x1F) - 1;
	tm->tm_year = bcd2bin(buf[9]) + 100;

	return 0;
	}

	static int nct3018y_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned char buf[4] = {0};
	int err;

	buf[0] = bin2bcd(tm->tm_sec);
	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SC, buf[0]);
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_SC\n");
	return err;
	}

	buf[0] = bin2bcd(tm->tm_min);
	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MN, buf[0]);
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_MN\n");
	return err;
	}

	buf[0] = bin2bcd(tm->tm_hour);
	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HR, buf[0]);
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_HR\n");
	return err;
	}

	buf[0] = tm->tm_wday & 0x07;
	buf[1] = bin2bcd(tm->tm_mday);
	buf[2] = bin2bcd(tm->tm_mon + 1);
	buf[3] = bin2bcd(tm->tm_year - 100);
	err = i2c_smbus_write_i2c_block_data(client, NCT3018Y_REG_DW,
	sizeof(buf), buf);
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write for day and mon and year\n");
	return -EIO;
	}

	return err;
	}

	static int nct3018y_rtc_read_alarm(struct device dev, struct rtc_wkalrm tm)
	{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned char buf[5];
	int err;

	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SCA,
	sizeof(buf), buf);
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to read date\n");
	return -EIO;
	}

	dev_dbg(&client->dev, "%s: raw data is sec=%02x, min=%02x hr=%02x\n",
	__func__, buf[0], buf[2], buf[4]);

	tm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
	tm->time.tm_min = bcd2bin(buf[2] & 0x7F);
	tm->time.tm_hour = bcd2bin(buf[4] & 0x3F);

	err = nct3018y_get_alarm_mode(client, &tm->enabled, &tm->pending);
	if (err < 0)
	return err;

	dev_dbg(&client->dev, "%s:s=%d m=%d, hr=%d, enabled=%d, pending=%d\n",
	__func__, tm->time.tm_sec, tm->time.tm_min,
	tm->time.tm_hour, tm->enabled, tm->pending);

	return 0;
	}

	static int nct3018y_rtc_set_alarm(struct device dev, struct rtc_wkalrm tm)
	{
	struct i2c_client *client = to_i2c_client(dev);
	int err;

	dev_dbg(dev, "%s, sec=%d, min=%d hour=%d tm->enabled:%d\n",
	__func__, tm->time.tm_sec, tm->time.tm_min, tm->time.tm_hour,
	tm->enabled);

	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SCA, bin2bcd(tm->time.tm_sec));
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_SCA\n");
	return err;
	}

	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MNA, bin2bcd(tm->time.tm_min));
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_MNA\n");
	return err;
	}

	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HRA, bin2bcd(tm->time.tm_hour));
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_HRA\n");
	return err;
	}

	return nct3018y_set_alarm_mode(client, tm->enabled);
	}

	static int nct3018y_irq_enable(struct device *dev, unsigned int enabled)
	{
	dev_dbg(dev, "%s: alarm enable=%d\n", __func__, enabled);

	return nct3018y_set_alarm_mode(to_i2c_client(dev), enabled);
	}

	static int nct3018y_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
	{
	struct i2c_client *client = to_i2c_client(dev);
	int status, flags = 0;

	switch (cmd) {
	case RTC_VL_READ:
	status = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
	if (status < 0)
	return status;

	if (!(status & NCT3018Y_REG_BAT_MASK))
	flags \|= RTC_VL_DATA_INVALID;

	return put_user(flags, (unsigned int __user *)arg);

	default:
	return -ENOIOCTLCMD;
	}
	}

	#ifdef CONFIG_COMMON_CLK
	/*
	* Handling of the clkout
	*/

	#define clkout_hw_to_nct3018y(_hw) container_of(_hw, struct nct3018y, clkout_hw)

	static const int clkout_rates[] = {
	32768,
	1024,
	32,
	1,
	};

	static unsigned long nct3018y_clkout_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate)
	{
	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
	struct i2c_client *client = nct3018y->client;
	int flags;

	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
	if (flags < 0)
	return 0;

	flags &= NCT3018Y_REG_CLKO_F_MASK;
	return clkout_rates[flags];
	}

	static long nct3018y_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long *prate)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
	if (clkout_rates[i] <= rate)
	return clkout_rates[i];

	return 0;
	}

	static int nct3018y_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long parent_rate)
	{
	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
	struct i2c_client *client = nct3018y->client;
	int i, flags;

	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
	if (flags < 0)
	return flags;

	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
	if (clkout_rates[i] == rate) {
	flags &= ~NCT3018Y_REG_CLKO_F_MASK;
	flags \|= i;
	return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
	}

	return -EINVAL;
	}

	static int nct3018y_clkout_control(struct clk_hw *hw, bool enable)
	{
	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
	struct i2c_client *client = nct3018y->client;
	int flags;

	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
	if (flags < 0)
	return flags;

	if (enable)
	flags \|= NCT3018Y_REG_CLKO_CKE;
	else
	flags &= ~NCT3018Y_REG_CLKO_CKE;

	return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
	}

	static int nct3018y_clkout_prepare(struct clk_hw *hw)
	{
	return nct3018y_clkout_control(hw, 1);
	}

	static void nct3018y_clkout_unprepare(struct clk_hw *hw)
	{
	nct3018y_clkout_control(hw, 0);
	}

	static int nct3018y_clkout_is_prepared(struct clk_hw *hw)
	{
	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
	struct i2c_client *client = nct3018y->client;
	int flags;

	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
	if (flags < 0)
	return flags;

	return flags & NCT3018Y_REG_CLKO_CKE;
	}

	static const struct clk_ops nct3018y_clkout_ops = {
	.prepare = nct3018y_clkout_prepare,
	.unprepare = nct3018y_clkout_unprepare,
	.is_prepared = nct3018y_clkout_is_prepared,
	.recalc_rate = nct3018y_clkout_recalc_rate,
	.round_rate = nct3018y_clkout_round_rate,
	.set_rate = nct3018y_clkout_set_rate,
	};

	static struct clk nct3018y_clkout_register_clk(struct nct3018y nct3018y)
	{
	struct i2c_client *client = nct3018y->client;
	struct device_node *node = client->dev.of_node;
	struct clk *clk;
	struct clk_init_data init;

	init.name = "nct3018y-clkout";
	init.ops = &nct3018y_clkout_ops;
	init.flags = 0;
	init.parent_names = NULL;
	init.num_parents = 0;
	nct3018y->clkout_hw.init = &init;

	/* optional override of the clockname */
	of_property_read_string(node, "clock-output-names", &init.name);

	/* register the clock */
	clk = devm_clk_register(&client->dev, &nct3018y->clkout_hw);

	if (!IS_ERR(clk))
	of_clk_add_provider(node, of_clk_src_simple_get, clk);

	return clk;
	}
	#endif

	static const struct rtc_class_ops nct3018y_rtc_ops = {
	.read_time = nct3018y_rtc_read_time,
	.set_time = nct3018y_rtc_set_time,
	.read_alarm = nct3018y_rtc_read_alarm,
	.set_alarm = nct3018y_rtc_set_alarm,
	.alarm_irq_enable = nct3018y_irq_enable,
	.ioctl = nct3018y_ioctl,
	};

	static int nct3018y_probe(struct i2c_client *client)
	{
	struct nct3018y *nct3018y;
	int err, flags;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C \|
	I2C_FUNC_SMBUS_BYTE \|
	I2C_FUNC_SMBUS_BLOCK_DATA))
	return -ENODEV;

	nct3018y = devm_kzalloc(&client->dev, sizeof(struct nct3018y),
	GFP_KERNEL);
	if (!nct3018y)
	return -ENOMEM;

	i2c_set_clientdata(client, nct3018y);
	nct3018y->client = client;
	device_set_wakeup_capable(&client->dev, 1);

	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
	if (flags < 0) {
	dev_dbg(&client->dev, "%s: read error\n", __func__);
	return flags;
	} else if (flags & NCT3018Y_BIT_TWO) {
	dev_dbg(&client->dev, "%s: NCT3018Y_BIT_TWO is set\n", __func__);
	}

	flags = NCT3018Y_BIT_TWO;
	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
	if (err < 0) {
	dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
	return err;
	}

	flags = 0;
	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
	if (err < 0) {
	dev_dbg(&client->dev, "%s: write error\n", __func__);
	return err;
	}

	nct3018y->rtc = devm_rtc_allocate_device(&client->dev);
	if (IS_ERR(nct3018y->rtc))
	return PTR_ERR(nct3018y->rtc);

	nct3018y->rtc->ops = &nct3018y_rtc_ops;
	nct3018y->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
	nct3018y->rtc->range_max = RTC_TIMESTAMP_END_2099;

	if (client->irq > 0) {
	err = devm_request_threaded_irq(&client->dev, client->irq,
	NULL, nct3018y_irq,
	IRQF_ONESHOT \| IRQF_TRIGGER_FALLING,
	"nct3018y", client);
	if (err) {
	dev_dbg(&client->dev, "unable to request IRQ %d\n", client->irq);
	return err;
	}
	} else {
	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, nct3018y->rtc->features);
	clear_bit(RTC_FEATURE_ALARM, nct3018y->rtc->features);
	}

	#ifdef CONFIG_COMMON_CLK
	/* register clk in common clk framework */
	nct3018y_clkout_register_clk(nct3018y);
	#endif

	return devm_rtc_register_device(nct3018y->rtc);
	}

	static const struct i2c_device_id nct3018y_id[] = {
	{ "nct3018y", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, nct3018y_id);

	static const struct of_device_id nct3018y_of_match[] = {
	{ .compatible = "nuvoton,nct3018y" },
	{}
	};
	MODULE_DEVICE_TABLE(of, nct3018y_of_match);

	static struct i2c_driver nct3018y_driver = {
	.driver = {
	.name = "rtc-nct3018y",
	.of_match_table = nct3018y_of_match,
	},
	.probe = nct3018y_probe,
	.id_table = nct3018y_id,
	};

	module_i2c_driver(nct3018y_driver);

	MODULE_AUTHOR("Medad CChien <ctcchien@nuvoton.com>");
	MODULE_AUTHOR("Mia Lin <mimi05633@gmail.com>");
	MODULE_DESCRIPTION("Nuvoton NCT3018Y RTC driver");
	MODULE_LICENSE("GPL");