drivers/rtc/rtc-rx8010.c - arm/linux - Git at Google

 /*
  * Driver for the Epson RTC module RX-8010 SJ
  *
  * Copyright(C) Timesys Corporation 2015
  * Copyright(C) General Electric Company 2015
  *
  * 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.
  *
  */

 #include <linux/bcd.h>
 #include <linux/bitops.h>
 #include <linux/i2c.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/rtc.h>

 #define RX8010_SEC     0x10
 #define RX8010_MIN     0x11
 #define RX8010_HOUR    0x12
 #define RX8010_WDAY    0x13
 #define RX8010_MDAY    0x14
 #define RX8010_MONTH   0x15
 #define RX8010_YEAR    0x16
 #define RX8010_RESV17  0x17
 #define RX8010_ALMIN   0x18
 #define RX8010_ALHOUR  0x19
 #define RX8010_ALWDAY  0x1A
 #define RX8010_TCOUNT0 0x1B
 #define RX8010_TCOUNT1 0x1C
 #define RX8010_EXT     0x1D
 #define RX8010_FLAG    0x1E
 #define RX8010_CTRL    0x1F
 /* 0x20 to 0x2F are user registers */
 #define RX8010_RESV30  0x30
 #define RX8010_RESV31  0x31
 #define RX8010_IRQ     0x32

 #define RX8010_EXT_WADA  BIT(3)

 #define RX8010_FLAG_VLF  BIT(1)
 #define RX8010_FLAG_AF   BIT(3)
 #define RX8010_FLAG_TF   BIT(4)
 #define RX8010_FLAG_UF   BIT(5)

 #define RX8010_CTRL_AIE  BIT(3)
 #define RX8010_CTRL_UIE  BIT(5)
 #define RX8010_CTRL_STOP BIT(6)
 #define RX8010_CTRL_TEST BIT(7)

 #define RX8010_ALARM_AE  BIT(7)

 static const struct i2c_device_id rx8010_id[] = {
 	{ "rx8010", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, rx8010_id);

 static const struct of_device_id rx8010_of_match[] = {
 	{ .compatible = "epson,rx8010" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, rx8010_of_match);

 struct rx8010_data {
 	struct i2c_client *client;
 	struct rtc_device *rtc;
 	u8 ctrlreg;
 };

 static irqreturn_t rx8010_irq_1_handler(int irq, void *dev_id)
 {
 	struct i2c_client *client = dev_id;
 	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
 	int flagreg;

 	mutex_lock(&rx8010->rtc->ops_lock);

 	flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);

 	if (flagreg <= 0) {
 		mutex_unlock(&rx8010->rtc->ops_lock);
 		return IRQ_NONE;
 	}

 	if (flagreg & RX8010_FLAG_VLF)
 		dev_warn(&client->dev, "Frequency stop detected\n");

 	if (flagreg & RX8010_FLAG_TF) {
 		flagreg &= ~RX8010_FLAG_TF;
 		rtc_update_irq(rx8010->rtc, 1, RTC_PF | RTC_IRQF);
 	}

 	if (flagreg & RX8010_FLAG_AF) {
 		flagreg &= ~RX8010_FLAG_AF;
 		rtc_update_irq(rx8010->rtc, 1, RTC_AF | RTC_IRQF);
 	}

 	if (flagreg & RX8010_FLAG_UF) {
 		flagreg &= ~RX8010_FLAG_UF;
 		rtc_update_irq(rx8010->rtc, 1, RTC_UF | RTC_IRQF);
 	}

 	i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);

 	mutex_unlock(&rx8010->rtc->ops_lock);
 	return IRQ_HANDLED;
 }

 static int rx8010_get_time(struct device *dev, struct rtc_time *dt)
 {
 	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
 	u8 date[7];
 	int flagreg;
 	int err;

 	flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
 	if (flagreg < 0)
 		return flagreg;

 	if (flagreg & RX8010_FLAG_VLF) {
 		dev_warn(dev, "Frequency stop detected\n");
 		return -EINVAL;
 	}

 	err = i2c_smbus_read_i2c_block_data(rx8010->client, RX8010_SEC,
 					    7, date);
 	if (err != 7)
 		return err < 0 ? err : -EIO;

 	dt->tm_sec = bcd2bin(date[RX8010_SEC - RX8010_SEC] & 0x7f);
 	dt->tm_min = bcd2bin(date[RX8010_MIN - RX8010_SEC] & 0x7f);
 	dt->tm_hour = bcd2bin(date[RX8010_HOUR - RX8010_SEC] & 0x3f);
 	dt->tm_mday = bcd2bin(date[RX8010_MDAY - RX8010_SEC] & 0x3f);
 	dt->tm_mon = bcd2bin(date[RX8010_MONTH - RX8010_SEC] & 0x1f) - 1;
 	dt->tm_year = bcd2bin(date[RX8010_YEAR - RX8010_SEC]) + 100;
 	dt->tm_wday = ffs(date[RX8010_WDAY - RX8010_SEC] & 0x7f);

 	return rtc_valid_tm(dt);
 }

 static int rx8010_set_time(struct device *dev, struct rtc_time *dt)
 {
 	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
 	u8 date[7];
 	int ctrl, flagreg;
 	int ret;

 	if ((dt->tm_year < 100) || (dt->tm_year > 199))
 		return -EINVAL;

 	/* set STOP bit before changing clock/calendar */
 	ctrl = i2c_smbus_read_byte_data(rx8010->client, RX8010_CTRL);
 	if (ctrl < 0)
 		return ctrl;
 	rx8010->ctrlreg = ctrl | RX8010_CTRL_STOP;
 	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
 					rx8010->ctrlreg);
 	if (ret < 0)
 		return ret;

 	date[RX8010_SEC - RX8010_SEC] = bin2bcd(dt->tm_sec);
 	date[RX8010_MIN - RX8010_SEC] = bin2bcd(dt->tm_min);
 	date[RX8010_HOUR - RX8010_SEC] = bin2bcd(dt->tm_hour);
 	date[RX8010_MDAY - RX8010_SEC] = bin2bcd(dt->tm_mday);
 	date[RX8010_MONTH - RX8010_SEC] = bin2bcd(dt->tm_mon + 1);
 	date[RX8010_YEAR - RX8010_SEC] = bin2bcd(dt->tm_year - 100);
 	date[RX8010_WDAY - RX8010_SEC] = bin2bcd(1 << dt->tm_wday);

 	ret = i2c_smbus_write_i2c_block_data(rx8010->client,
 					     RX8010_SEC, 7, date);
 	if (ret < 0)
 		return ret;

 	/* clear STOP bit after changing clock/calendar */
 	ctrl = i2c_smbus_read_byte_data(rx8010->client, RX8010_CTRL);
 	if (ctrl < 0)
 		return ctrl;
 	rx8010->ctrlreg = ctrl & ~RX8010_CTRL_STOP;
 	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
 					rx8010->ctrlreg);
 	if (ret < 0)
 		return ret;

 	flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
 	if (flagreg < 0) {
 		return flagreg;
 	}

 	if (flagreg & RX8010_FLAG_VLF)
 		ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG,
 						flagreg & ~RX8010_FLAG_VLF);

 	return 0;
 }

 static int rx8010_init_client(struct i2c_client *client)
 {
 	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
 	u8 ctrl[2];
 	int need_clear = 0, err = 0;

 	/* Initialize reserved registers as specified in datasheet */
 	err = i2c_smbus_write_byte_data(client, RX8010_RESV17, 0xD8);
 	if (err < 0)
 		return err;

 	err = i2c_smbus_write_byte_data(client, RX8010_RESV30, 0x00);
 	if (err < 0)
 		return err;

 	err = i2c_smbus_write_byte_data(client, RX8010_RESV31, 0x08);
 	if (err < 0)
 		return err;

 	err = i2c_smbus_write_byte_data(client, RX8010_IRQ, 0x00);
 	if (err < 0)
 		return err;

 	err = i2c_smbus_read_i2c_block_data(rx8010->client, RX8010_FLAG,
 					    2, ctrl);
 	if (err != 2)
 		return err < 0 ? err : -EIO;

 	if (ctrl[0] & RX8010_FLAG_VLF)
 		dev_warn(&client->dev, "Frequency stop was detected\n");

 	if (ctrl[0] & RX8010_FLAG_AF) {
 		dev_warn(&client->dev, "Alarm was detected\n");
 		need_clear = 1;
 	}

 	if (ctrl[0] & RX8010_FLAG_TF)
 		need_clear = 1;

 	if (ctrl[0] & RX8010_FLAG_UF)
 		need_clear = 1;

 	if (need_clear) {
 		ctrl[0] &= ~(RX8010_FLAG_AF | RX8010_FLAG_TF | RX8010_FLAG_UF);
 		err = i2c_smbus_write_byte_data(client, RX8010_FLAG, ctrl[0]);
 		if (err < 0)
 			return err;
 	}

 	rx8010->ctrlreg = (ctrl[1] & ~RX8010_CTRL_TEST);

 	return 0;
 }

 static int rx8010_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 {
 	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
 	struct i2c_client *client = rx8010->client;
 	u8 alarmvals[3];
 	int flagreg;
 	int err;

 	err = i2c_smbus_read_i2c_block_data(client, RX8010_ALMIN, 3, alarmvals);
 	if (err != 3)
 		return err < 0 ? err : -EIO;

 	flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);
 	if (flagreg < 0)
 		return flagreg;

 	t->time.tm_sec = 0;
 	t->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
 	t->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);

 	if (!(alarmvals[2] & RX8010_ALARM_AE))
 		t->time.tm_mday = bcd2bin(alarmvals[2] & 0x7f);

 	t->enabled = !!(rx8010->ctrlreg & RX8010_CTRL_AIE);
 	t->pending = (flagreg & RX8010_FLAG_AF) && t->enabled;

 	return 0;
 }

 static int rx8010_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
 	u8 alarmvals[3];
 	int extreg, flagreg;
 	int err;

 	flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);
 	if (flagreg < 0) {
 		return flagreg;
 	}

 	if (rx8010->ctrlreg & (RX8010_CTRL_AIE | RX8010_CTRL_UIE)) {
 		rx8010->ctrlreg &= ~(RX8010_CTRL_AIE | RX8010_CTRL_UIE);
 		err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
 						rx8010->ctrlreg);
 		if (err < 0) {
 			return err;
 		}
 	}

 	flagreg &= ~RX8010_FLAG_AF;
 	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, flagreg);
 	if (err < 0)
 		return err;

 	alarmvals[0] = bin2bcd(t->time.tm_min);
 	alarmvals[1] = bin2bcd(t->time.tm_hour);
 	alarmvals[2] = bin2bcd(t->time.tm_mday);

 	err = i2c_smbus_write_i2c_block_data(rx8010->client, RX8010_ALMIN,
 					     2, alarmvals);
 	if (err < 0)
 		return err;

 	extreg = i2c_smbus_read_byte_data(client, RX8010_EXT);
 	if (extreg < 0)
 		return extreg;

 	extreg |= RX8010_EXT_WADA;
 	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_EXT, extreg);
 	if (err < 0)
 		return err;

 	if (alarmvals[2] == 0)
 		alarmvals[2] |= RX8010_ALARM_AE;

 	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_ALWDAY,
 					alarmvals[2]);
 	if (err < 0)
 		return err;

 	if (t->enabled) {
 		if (rx8010->rtc->uie_rtctimer.enabled)
 			rx8010->ctrlreg |= RX8010_CTRL_UIE;
 		if (rx8010->rtc->aie_timer.enabled)
 			rx8010->ctrlreg |=
 				(RX8010_CTRL_AIE | RX8010_CTRL_UIE);

 		err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
 						rx8010->ctrlreg);
 		if (err < 0)
 			return err;
 	}

 	return 0;
 }

 static int rx8010_alarm_irq_enable(struct device *dev,
 				   unsigned int enabled)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
 	int flagreg;
 	u8 ctrl;
 	int err;

 	ctrl = rx8010->ctrlreg;

 	if (enabled) {
 		if (rx8010->rtc->uie_rtctimer.enabled)
 			ctrl |= RX8010_CTRL_UIE;
 		if (rx8010->rtc->aie_timer.enabled)
 			ctrl |= (RX8010_CTRL_AIE | RX8010_CTRL_UIE);
 	} else {
 		if (!rx8010->rtc->uie_rtctimer.enabled)
 			ctrl &= ~RX8010_CTRL_UIE;
 		if (!rx8010->rtc->aie_timer.enabled)
 			ctrl &= ~RX8010_CTRL_AIE;
 	}

 	flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);
 	if (flagreg < 0)
 		return flagreg;

 	flagreg &= ~RX8010_FLAG_AF;
 	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, flagreg);
 	if (err < 0)
 		return err;

 	if (ctrl != rx8010->ctrlreg) {
 		rx8010->ctrlreg = ctrl;
 		err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
 						rx8010->ctrlreg);
 		if (err < 0)
 			return err;
 	}

 	return 0;
 }

 static int rx8010_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
 	int ret, tmp;
 	int flagreg;

 	switch (cmd) {
 	case RTC_VL_READ:
 		flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
 		if (flagreg < 0)
 			return flagreg;

 		tmp = !!(flagreg & RX8010_FLAG_VLF);
 		if (copy_to_user((void __user *)arg, &tmp, sizeof(int)))
 			return -EFAULT;

 		return 0;

 	case RTC_VL_CLR:
 		flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
 		if (flagreg < 0) {
 			return flagreg;
 		}

 		flagreg &= ~RX8010_FLAG_VLF;
 		ret = i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);
 		if (ret < 0)
 			return ret;

 		return 0;

 	default:
 		return -ENOIOCTLCMD;
 	}
 }

 static struct rtc_class_ops rx8010_rtc_ops = {
 	.read_time = rx8010_get_time,
 	.set_time = rx8010_set_time,
 	.ioctl = rx8010_ioctl,
 };

 static int rx8010_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 	struct rx8010_data *rx8010;
 	int err = 0;

 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 		| I2C_FUNC_SMBUS_I2C_BLOCK)) {
 		dev_err(&adapter->dev, "doesn't support required functionality\n");
 		return -EIO;
 	}

 	rx8010 = devm_kzalloc(&client->dev, sizeof(struct rx8010_data),
 			      GFP_KERNEL);
 	if (!rx8010)
 		return -ENOMEM;

 	rx8010->client = client;
 	i2c_set_clientdata(client, rx8010);

 	err = rx8010_init_client(client);
 	if (err)
 		return err;

 	if (client->irq > 0) {
 		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 						rx8010_irq_1_handler,
 						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 						"rx8010", client);

 		if (err) {
 			dev_err(&client->dev, "unable to request IRQ\n");
 			client->irq = 0;
 		} else {
 			rx8010_rtc_ops.read_alarm = rx8010_read_alarm;
 			rx8010_rtc_ops.set_alarm = rx8010_set_alarm;
 			rx8010_rtc_ops.alarm_irq_enable = rx8010_alarm_irq_enable;
 		}
 	}

 	rx8010->rtc = devm_rtc_device_register(&client->dev, client->name,
 		&rx8010_rtc_ops, THIS_MODULE);

 	if (IS_ERR(rx8010->rtc)) {
 		dev_err(&client->dev, "unable to register the class device\n");
 		return PTR_ERR(rx8010->rtc);
 	}

 	rx8010->rtc->max_user_freq = 1;

 	return err;
 }

 static struct i2c_driver rx8010_driver = {
 	.driver = {
 		.name = "rtc-rx8010",
 		.of_match_table = of_match_ptr(rx8010_of_match),
 	},
 	.probe		= rx8010_probe,
 	.id_table	= rx8010_id,
 };

 module_i2c_driver(rx8010_driver);

 MODULE_AUTHOR("Akshay Bhat <akshay.bhat@timesys.com>");
 MODULE_DESCRIPTION("Epson RX8010SJ RTC driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Driver for the Epson RTC module RX-8010 SJ
	*
	* Copyright(C) Timesys Corporation 2015
	* Copyright(C) General Electric Company 2015
	*
	* 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.
	*
	*/

	#include <linux/bcd.h>
	#include <linux/bitops.h>
	#include <linux/i2c.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/rtc.h>

	#define RX8010_SEC 0x10
	#define RX8010_MIN 0x11
	#define RX8010_HOUR 0x12
	#define RX8010_WDAY 0x13
	#define RX8010_MDAY 0x14
	#define RX8010_MONTH 0x15
	#define RX8010_YEAR 0x16
	#define RX8010_RESV17 0x17
	#define RX8010_ALMIN 0x18
	#define RX8010_ALHOUR 0x19
	#define RX8010_ALWDAY 0x1A
	#define RX8010_TCOUNT0 0x1B
	#define RX8010_TCOUNT1 0x1C
	#define RX8010_EXT 0x1D
	#define RX8010_FLAG 0x1E
	#define RX8010_CTRL 0x1F
	/* 0x20 to 0x2F are user registers */
	#define RX8010_RESV30 0x30
	#define RX8010_RESV31 0x31
	#define RX8010_IRQ 0x32

	#define RX8010_EXT_WADA BIT(3)

	#define RX8010_FLAG_VLF BIT(1)
	#define RX8010_FLAG_AF BIT(3)
	#define RX8010_FLAG_TF BIT(4)
	#define RX8010_FLAG_UF BIT(5)

	#define RX8010_CTRL_AIE BIT(3)
	#define RX8010_CTRL_UIE BIT(5)
	#define RX8010_CTRL_STOP BIT(6)
	#define RX8010_CTRL_TEST BIT(7)

	#define RX8010_ALARM_AE BIT(7)

	static const struct i2c_device_id rx8010_id[] = {
	{ "rx8010", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, rx8010_id);

	static const struct of_device_id rx8010_of_match[] = {
	{ .compatible = "epson,rx8010" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, rx8010_of_match);

	struct rx8010_data {
	struct i2c_client *client;
	struct rtc_device *rtc;
	u8 ctrlreg;
	};

	static irqreturn_t rx8010_irq_1_handler(int irq, void *dev_id)
	{
	struct i2c_client *client = dev_id;
	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
	int flagreg;

	mutex_lock(&rx8010->rtc->ops_lock);

	flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);

	if (flagreg <= 0) {
	mutex_unlock(&rx8010->rtc->ops_lock);
	return IRQ_NONE;
	}

	if (flagreg & RX8010_FLAG_VLF)
	dev_warn(&client->dev, "Frequency stop detected\n");

	if (flagreg & RX8010_FLAG_TF) {
	flagreg &= ~RX8010_FLAG_TF;
	rtc_update_irq(rx8010->rtc, 1, RTC_PF \| RTC_IRQF);
	}

	if (flagreg & RX8010_FLAG_AF) {
	flagreg &= ~RX8010_FLAG_AF;
	rtc_update_irq(rx8010->rtc, 1, RTC_AF \| RTC_IRQF);
	}

	if (flagreg & RX8010_FLAG_UF) {
	flagreg &= ~RX8010_FLAG_UF;
	rtc_update_irq(rx8010->rtc, 1, RTC_UF \| RTC_IRQF);
	}

	i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);

	mutex_unlock(&rx8010->rtc->ops_lock);
	return IRQ_HANDLED;
	}

	static int rx8010_get_time(struct device dev, struct rtc_time dt)
	{
	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
	u8 date[7];
	int flagreg;
	int err;

	flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
	if (flagreg < 0)
	return flagreg;

	if (flagreg & RX8010_FLAG_VLF) {
	dev_warn(dev, "Frequency stop detected\n");
	return -EINVAL;
	}

	err = i2c_smbus_read_i2c_block_data(rx8010->client, RX8010_SEC,
	7, date);
	if (err != 7)
	return err < 0 ? err : -EIO;

	dt->tm_sec = bcd2bin(date[RX8010_SEC - RX8010_SEC] & 0x7f);
	dt->tm_min = bcd2bin(date[RX8010_MIN - RX8010_SEC] & 0x7f);
	dt->tm_hour = bcd2bin(date[RX8010_HOUR - RX8010_SEC] & 0x3f);
	dt->tm_mday = bcd2bin(date[RX8010_MDAY - RX8010_SEC] & 0x3f);
	dt->tm_mon = bcd2bin(date[RX8010_MONTH - RX8010_SEC] & 0x1f) - 1;
	dt->tm_year = bcd2bin(date[RX8010_YEAR - RX8010_SEC]) + 100;
	dt->tm_wday = ffs(date[RX8010_WDAY - RX8010_SEC] & 0x7f);

	return rtc_valid_tm(dt);
	}

	static int rx8010_set_time(struct device dev, struct rtc_time dt)
	{
	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
	u8 date[7];
	int ctrl, flagreg;
	int ret;

	if ((dt->tm_year < 100) \|\| (dt->tm_year > 199))
	return -EINVAL;

	/* set STOP bit before changing clock/calendar */
	ctrl = i2c_smbus_read_byte_data(rx8010->client, RX8010_CTRL);
	if (ctrl < 0)
	return ctrl;
	rx8010->ctrlreg = ctrl \| RX8010_CTRL_STOP;
	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
	rx8010->ctrlreg);
	if (ret < 0)
	return ret;

	date[RX8010_SEC - RX8010_SEC] = bin2bcd(dt->tm_sec);
	date[RX8010_MIN - RX8010_SEC] = bin2bcd(dt->tm_min);
	date[RX8010_HOUR - RX8010_SEC] = bin2bcd(dt->tm_hour);
	date[RX8010_MDAY - RX8010_SEC] = bin2bcd(dt->tm_mday);
	date[RX8010_MONTH - RX8010_SEC] = bin2bcd(dt->tm_mon + 1);
	date[RX8010_YEAR - RX8010_SEC] = bin2bcd(dt->tm_year - 100);
	date[RX8010_WDAY - RX8010_SEC] = bin2bcd(1 << dt->tm_wday);

	ret = i2c_smbus_write_i2c_block_data(rx8010->client,
	RX8010_SEC, 7, date);
	if (ret < 0)
	return ret;

	/* clear STOP bit after changing clock/calendar */
	ctrl = i2c_smbus_read_byte_data(rx8010->client, RX8010_CTRL);
	if (ctrl < 0)
	return ctrl;
	rx8010->ctrlreg = ctrl & ~RX8010_CTRL_STOP;
	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
	rx8010->ctrlreg);
	if (ret < 0)
	return ret;

	flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
	if (flagreg < 0) {
	return flagreg;
	}

	if (flagreg & RX8010_FLAG_VLF)
	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG,
	flagreg & ~RX8010_FLAG_VLF);

	return 0;
	}

	static int rx8010_init_client(struct i2c_client *client)
	{
	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
	u8 ctrl[2];
	int need_clear = 0, err = 0;

	/* Initialize reserved registers as specified in datasheet */
	err = i2c_smbus_write_byte_data(client, RX8010_RESV17, 0xD8);
	if (err < 0)
	return err;

	err = i2c_smbus_write_byte_data(client, RX8010_RESV30, 0x00);
	if (err < 0)
	return err;

	err = i2c_smbus_write_byte_data(client, RX8010_RESV31, 0x08);
	if (err < 0)
	return err;

	err = i2c_smbus_write_byte_data(client, RX8010_IRQ, 0x00);
	if (err < 0)
	return err;

	err = i2c_smbus_read_i2c_block_data(rx8010->client, RX8010_FLAG,
	2, ctrl);
	if (err != 2)
	return err < 0 ? err : -EIO;

	if (ctrl[0] & RX8010_FLAG_VLF)
	dev_warn(&client->dev, "Frequency stop was detected\n");

	if (ctrl[0] & RX8010_FLAG_AF) {
	dev_warn(&client->dev, "Alarm was detected\n");
	need_clear = 1;
	}

	if (ctrl[0] & RX8010_FLAG_TF)
	need_clear = 1;

	if (ctrl[0] & RX8010_FLAG_UF)
	need_clear = 1;

	if (need_clear) {
	ctrl[0] &= ~(RX8010_FLAG_AF \| RX8010_FLAG_TF \| RX8010_FLAG_UF);
	err = i2c_smbus_write_byte_data(client, RX8010_FLAG, ctrl[0]);
	if (err < 0)
	return err;
	}

	rx8010->ctrlreg = (ctrl[1] & ~RX8010_CTRL_TEST);

	return 0;
	}

	static int rx8010_read_alarm(struct device dev, struct rtc_wkalrm t)
	{
	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
	struct i2c_client *client = rx8010->client;
	u8 alarmvals[3];
	int flagreg;
	int err;

	err = i2c_smbus_read_i2c_block_data(client, RX8010_ALMIN, 3, alarmvals);
	if (err != 3)
	return err < 0 ? err : -EIO;

	flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);
	if (flagreg < 0)
	return flagreg;

	t->time.tm_sec = 0;
	t->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
	t->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);

	if (!(alarmvals[2] & RX8010_ALARM_AE))
	t->time.tm_mday = bcd2bin(alarmvals[2] & 0x7f);

	t->enabled = !!(rx8010->ctrlreg & RX8010_CTRL_AIE);
	t->pending = (flagreg & RX8010_FLAG_AF) && t->enabled;

	return 0;
	}

	static int rx8010_set_alarm(struct device dev, struct rtc_wkalrm t)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
	u8 alarmvals[3];
	int extreg, flagreg;
	int err;

	flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);
	if (flagreg < 0) {
	return flagreg;
	}

	if (rx8010->ctrlreg & (RX8010_CTRL_AIE \| RX8010_CTRL_UIE)) {
	rx8010->ctrlreg &= ~(RX8010_CTRL_AIE \| RX8010_CTRL_UIE);
	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
	rx8010->ctrlreg);
	if (err < 0) {
	return err;
	}
	}

	flagreg &= ~RX8010_FLAG_AF;
	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, flagreg);
	if (err < 0)
	return err;

	alarmvals[0] = bin2bcd(t->time.tm_min);
	alarmvals[1] = bin2bcd(t->time.tm_hour);
	alarmvals[2] = bin2bcd(t->time.tm_mday);

	err = i2c_smbus_write_i2c_block_data(rx8010->client, RX8010_ALMIN,
	2, alarmvals);
	if (err < 0)
	return err;

	extreg = i2c_smbus_read_byte_data(client, RX8010_EXT);
	if (extreg < 0)
	return extreg;

	extreg \|= RX8010_EXT_WADA;
	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_EXT, extreg);
	if (err < 0)
	return err;

	if (alarmvals[2] == 0)
	alarmvals[2] \|= RX8010_ALARM_AE;

	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_ALWDAY,
	alarmvals[2]);
	if (err < 0)
	return err;

	if (t->enabled) {
	if (rx8010->rtc->uie_rtctimer.enabled)
	rx8010->ctrlreg \|= RX8010_CTRL_UIE;
	if (rx8010->rtc->aie_timer.enabled)
	rx8010->ctrlreg \|=
	(RX8010_CTRL_AIE \| RX8010_CTRL_UIE);

	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
	rx8010->ctrlreg);
	if (err < 0)
	return err;
	}

	return 0;
	}

	static int rx8010_alarm_irq_enable(struct device *dev,
	unsigned int enabled)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
	int flagreg;
	u8 ctrl;
	int err;

	ctrl = rx8010->ctrlreg;

	if (enabled) {
	if (rx8010->rtc->uie_rtctimer.enabled)
	ctrl \|= RX8010_CTRL_UIE;
	if (rx8010->rtc->aie_timer.enabled)
	ctrl \|= (RX8010_CTRL_AIE \| RX8010_CTRL_UIE);
	} else {
	if (!rx8010->rtc->uie_rtctimer.enabled)
	ctrl &= ~RX8010_CTRL_UIE;
	if (!rx8010->rtc->aie_timer.enabled)
	ctrl &= ~RX8010_CTRL_AIE;
	}

	flagreg = i2c_smbus_read_byte_data(client, RX8010_FLAG);
	if (flagreg < 0)
	return flagreg;

	flagreg &= ~RX8010_FLAG_AF;
	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, flagreg);
	if (err < 0)
	return err;

	if (ctrl != rx8010->ctrlreg) {
	rx8010->ctrlreg = ctrl;
	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
	rx8010->ctrlreg);
	if (err < 0)
	return err;
	}

	return 0;
	}

	static int rx8010_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
	int ret, tmp;
	int flagreg;

	switch (cmd) {
	case RTC_VL_READ:
	flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
	if (flagreg < 0)
	return flagreg;

	tmp = !!(flagreg & RX8010_FLAG_VLF);
	if (copy_to_user((void __user *)arg, &tmp, sizeof(int)))
	return -EFAULT;

	return 0;

	case RTC_VL_CLR:
	flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
	if (flagreg < 0) {
	return flagreg;
	}

	flagreg &= ~RX8010_FLAG_VLF;
	ret = i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);
	if (ret < 0)
	return ret;

	return 0;

	default:
	return -ENOIOCTLCMD;
	}
	}

	static struct rtc_class_ops rx8010_rtc_ops = {
	.read_time = rx8010_get_time,
	.set_time = rx8010_set_time,
	.ioctl = rx8010_ioctl,
	};

	static int rx8010_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
	struct rx8010_data *rx8010;
	int err = 0;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
	\| I2C_FUNC_SMBUS_I2C_BLOCK)) {
	dev_err(&adapter->dev, "doesn't support required functionality\n");
	return -EIO;
	}

	rx8010 = devm_kzalloc(&client->dev, sizeof(struct rx8010_data),
	GFP_KERNEL);
	if (!rx8010)
	return -ENOMEM;

	rx8010->client = client;
	i2c_set_clientdata(client, rx8010);

	err = rx8010_init_client(client);
	if (err)
	return err;

	if (client->irq > 0) {
	dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
	err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
	rx8010_irq_1_handler,
	IRQF_TRIGGER_LOW \| IRQF_ONESHOT,
	"rx8010", client);

	if (err) {
	dev_err(&client->dev, "unable to request IRQ\n");
	client->irq = 0;
	} else {
	rx8010_rtc_ops.read_alarm = rx8010_read_alarm;
	rx8010_rtc_ops.set_alarm = rx8010_set_alarm;
	rx8010_rtc_ops.alarm_irq_enable = rx8010_alarm_irq_enable;
	}
	}

	rx8010->rtc = devm_rtc_device_register(&client->dev, client->name,
	&rx8010_rtc_ops, THIS_MODULE);

	if (IS_ERR(rx8010->rtc)) {
	dev_err(&client->dev, "unable to register the class device\n");
	return PTR_ERR(rx8010->rtc);
	}

	rx8010->rtc->max_user_freq = 1;

	return err;
	}

	static struct i2c_driver rx8010_driver = {
	.driver = {
	.name = "rtc-rx8010",
	.of_match_table = of_match_ptr(rx8010_of_match),
	},
	.probe = rx8010_probe,
	.id_table = rx8010_id,
	};

	module_i2c_driver(rx8010_driver);

	MODULE_AUTHOR("Akshay Bhat <akshay.bhat@timesys.com>");
	MODULE_DESCRIPTION("Epson RX8010SJ RTC driver");
	MODULE_LICENSE("GPL v2");