drivers/rtc/rtc-rv8803.c - kernel/quantenna - Git at Google

 /*
  * RTC driver for the Micro Crystal RV8803
  *
  * Copyright (C) 2015 Micro Crystal SA
  *
  * Alexandre Belloni <alexandre.belloni@free-electrons.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.
  *
  */

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

 #define RV8803_SEC			0x00
 #define RV8803_MIN			0x01
 #define RV8803_HOUR			0x02
 #define RV8803_WEEK			0x03
 #define RV8803_DAY			0x04
 #define RV8803_MONTH			0x05
 #define RV8803_YEAR			0x06
 #define RV8803_RAM			0x07
 #define RV8803_ALARM_MIN		0x08
 #define RV8803_ALARM_HOUR		0x09
 #define RV8803_ALARM_WEEK_OR_DAY	0x0A
 #define RV8803_EXT			0x0D
 #define RV8803_FLAG			0x0E
 #define RV8803_CTRL			0x0F

 #define RV8803_EXT_WADA			BIT(6)

 #define RV8803_FLAG_V1F			BIT(0)
 #define RV8803_FLAG_V2F			BIT(1)
 #define RV8803_FLAG_AF			BIT(3)
 #define RV8803_FLAG_TF			BIT(4)
 #define RV8803_FLAG_UF			BIT(5)

 #define RV8803_CTRL_RESET		BIT(0)

 #define RV8803_CTRL_EIE			BIT(2)
 #define RV8803_CTRL_AIE			BIT(3)
 #define RV8803_CTRL_TIE			BIT(4)
 #define RV8803_CTRL_UIE			BIT(5)

 struct rv8803_data {
 	struct i2c_client *client;
 	struct rtc_device *rtc;
 	struct mutex flags_lock;
 	u8 ctrl;
 };

 static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
 {
 	struct i2c_client *client = dev_id;
 	struct rv8803_data *rv8803 = i2c_get_clientdata(client);
 	unsigned long events = 0;
 	int flags, try = 0;

 	mutex_lock(&rv8803->flags_lock);

 	do {
 		flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 		try++;
 	} while ((flags == -ENXIO) && (try < 3));
 	if (flags <= 0) {
 		mutex_unlock(&rv8803->flags_lock);
 		return IRQ_NONE;
 	}

 	if (flags & RV8803_FLAG_V1F)
 		dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");

 	if (flags & RV8803_FLAG_V2F)
 		dev_warn(&client->dev, "Voltage low, data loss detected.\n");

 	if (flags & RV8803_FLAG_TF) {
 		flags &= ~RV8803_FLAG_TF;
 		rv8803->ctrl &= ~RV8803_CTRL_TIE;
 		events |= RTC_PF;
 	}

 	if (flags & RV8803_FLAG_AF) {
 		flags &= ~RV8803_FLAG_AF;
 		rv8803->ctrl &= ~RV8803_CTRL_AIE;
 		events |= RTC_AF;
 	}

 	if (flags & RV8803_FLAG_UF) {
 		flags &= ~RV8803_FLAG_UF;
 		rv8803->ctrl &= ~RV8803_CTRL_UIE;
 		events |= RTC_UF;
 	}

 	if (events) {
 		rtc_update_irq(rv8803->rtc, 1, events);
 		i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
 		i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
 					  rv8803->ctrl);
 	}

 	mutex_unlock(&rv8803->flags_lock);

 	return IRQ_HANDLED;
 }

 static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
 {
 	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 	u8 date1[7];
 	u8 date2[7];
 	u8 *date = date1;
 	int ret, flags;

 	flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
 	if (flags < 0)
 		return flags;

 	if (flags & RV8803_FLAG_V2F) {
 		dev_warn(dev, "Voltage low, data is invalid.\n");
 		return -EINVAL;
 	}

 	ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
 					    7, date);
 	if (ret != 7)
 		return ret < 0 ? ret : -EIO;

 	if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
 		ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
 						    7, date2);
 		if (ret != 7)
 			return ret < 0 ? ret : -EIO;

 		if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
 			date = date2;
 	}

 	tm->tm_sec  = bcd2bin(date[RV8803_SEC] & 0x7f);
 	tm->tm_min  = bcd2bin(date[RV8803_MIN] & 0x7f);
 	tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
 	tm->tm_wday = ffs(date[RV8803_WEEK] & 0x7f);
 	tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
 	tm->tm_mon  = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
 	tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;

 	return rtc_valid_tm(tm);
 }

 static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 	u8 date[7];
 	int flags, ret;

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

 	date[RV8803_SEC]   = bin2bcd(tm->tm_sec);
 	date[RV8803_MIN]   = bin2bcd(tm->tm_min);
 	date[RV8803_HOUR]  = bin2bcd(tm->tm_hour);
 	date[RV8803_WEEK]  = 1 << (tm->tm_wday);
 	date[RV8803_DAY]   = bin2bcd(tm->tm_mday);
 	date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
 	date[RV8803_YEAR]  = bin2bcd(tm->tm_year - 100);

 	ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC,
 					     7, date);
 	if (ret < 0)
 		return ret;

 	mutex_lock(&rv8803->flags_lock);

 	flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
 	if (flags < 0) {
 		mutex_unlock(&rv8803->flags_lock);
 		return flags;
 	}

 	ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
 					flags & ~RV8803_FLAG_V2F);

 	mutex_unlock(&rv8803->flags_lock);

 	return ret;
 }

 static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 	struct i2c_client *client = rv8803->client;
 	u8 alarmvals[3];
 	int flags, ret;

 	ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN,
 					    3, alarmvals);
 	if (ret != 3)
 		return ret < 0 ? ret : -EIO;

 	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 	if (flags < 0)
 		return flags;

 	alrm->time.tm_sec  = 0;
 	alrm->time.tm_min  = bcd2bin(alarmvals[0] & 0x7f);
 	alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
 	alrm->time.tm_wday = -1;
 	alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
 	alrm->time.tm_mon  = -1;
 	alrm->time.tm_year = -1;

 	alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
 	alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;

 	return 0;
 }

 static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 	u8 alarmvals[3];
 	u8 ctrl[2];
 	int ret, err;

 	/* The alarm has no seconds, round up to nearest minute */
 	if (alrm->time.tm_sec) {
 		time64_t alarm_time = rtc_tm_to_time64(&alrm->time);

 		alarm_time += 60 - alrm->time.tm_sec;
 		rtc_time64_to_tm(alarm_time, &alrm->time);
 	}

 	mutex_lock(&rv8803->flags_lock);

 	ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
 	if (ret != 2) {
 		mutex_unlock(&rv8803->flags_lock);
 		return ret < 0 ? ret : -EIO;
 	}

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

 	if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
 		rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
 		err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
 						rv8803->ctrl);
 		if (err) {
 			mutex_unlock(&rv8803->flags_lock);
 			return err;
 		}
 	}

 	ctrl[1] &= ~RV8803_FLAG_AF;
 	err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
 	mutex_unlock(&rv8803->flags_lock);
 	if (err)
 		return err;

 	err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN,
 					     3, alarmvals);
 	if (err)
 		return err;

 	if (alrm->enabled) {
 		if (rv8803->rtc->uie_rtctimer.enabled)
 			rv8803->ctrl |= RV8803_CTRL_UIE;
 		if (rv8803->rtc->aie_timer.enabled)
 			rv8803->ctrl |= RV8803_CTRL_AIE;

 		err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
 						rv8803->ctrl);
 		if (err)
 			return err;
 	}

 	return 0;
 }

 static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 	int ctrl, flags, err;

 	ctrl = rv8803->ctrl;

 	if (enabled) {
 		if (rv8803->rtc->uie_rtctimer.enabled)
 			ctrl |= RV8803_CTRL_UIE;
 		if (rv8803->rtc->aie_timer.enabled)
 			ctrl |= RV8803_CTRL_AIE;
 	} else {
 		if (!rv8803->rtc->uie_rtctimer.enabled)
 			ctrl &= ~RV8803_CTRL_UIE;
 		if (!rv8803->rtc->aie_timer.enabled)
 			ctrl &= ~RV8803_CTRL_AIE;
 	}

 	mutex_lock(&rv8803->flags_lock);
 	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 	if (flags < 0) {
 		mutex_unlock(&rv8803->flags_lock);
 		return flags;
 	}
 	flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
 	err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
 	mutex_unlock(&rv8803->flags_lock);
 	if (err)
 		return err;

 	if (ctrl != rv8803->ctrl) {
 		rv8803->ctrl = ctrl;
 		err = i2c_smbus_write_byte_data(client, RV8803_CTRL,
 						rv8803->ctrl);
 		if (err)
 			return err;
 	}

 	return 0;
 }

 static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 	int flags, ret = 0;

 	switch (cmd) {
 	case RTC_VL_READ:
 		flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 		if (flags < 0)
 			return flags;

 		if (flags & RV8803_FLAG_V1F)
 			dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");

 		if (flags & RV8803_FLAG_V2F)
 			dev_warn(&client->dev, "Voltage low, data loss detected.\n");

 		flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;

 		if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
 			return -EFAULT;

 		return 0;

 	case RTC_VL_CLR:
 		mutex_lock(&rv8803->flags_lock);
 		flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 		if (flags < 0) {
 			mutex_unlock(&rv8803->flags_lock);
 			return flags;
 		}

 		flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
 		ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
 		mutex_unlock(&rv8803->flags_lock);
 		if (ret < 0)
 			return ret;

 		return 0;

 	default:
 		return -ENOIOCTLCMD;
 	}
 }

 static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj,
 				  struct bin_attribute *attr,
 				  char *buf, loff_t off, size_t count)
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct i2c_client *client = to_i2c_client(dev);
 	int ret;

 	ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]);
 	if (ret < 0)
 		return ret;

 	return 1;
 }

 static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj,
 				 struct bin_attribute *attr,
 				 char *buf, loff_t off, size_t count)
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct i2c_client *client = to_i2c_client(dev);
 	int ret;

 	ret = i2c_smbus_read_byte_data(client, RV8803_RAM);
 	if (ret < 0)
 		return ret;

 	buf[0] = ret;

 	return 1;
 }

 static struct bin_attribute rv8803_nvram_attr = {
 	.attr = {
 		.name = "nvram",
 		.mode = S_IRUGO | S_IWUSR,
 	},
 	.size = 1,
 	.read = rv8803_nvram_read,
 	.write = rv8803_nvram_write,
 };

 static struct rtc_class_ops rv8803_rtc_ops = {
 	.read_time = rv8803_get_time,
 	.set_time = rv8803_set_time,
 	.ioctl = rv8803_ioctl,
 };

 static int rv8803_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 	struct rv8803_data *rv8803;
 	int err, flags, try = 0;

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

 	rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
 			      GFP_KERNEL);
 	if (!rv8803)
 		return -ENOMEM;

 	mutex_init(&rv8803->flags_lock);
 	rv8803->client = client;
 	i2c_set_clientdata(client, rv8803);

 	/*
 	 * There is a 60µs window where the RTC may not reply on the i2c bus in
 	 * that case, the transfer is not ACKed. In that case, ensure there are
 	 * multiple attempts.
 	 */
 	do {
 		flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 		try++;
 	} while ((flags == -ENXIO) && (try < 3));

 	if (flags < 0)
 		return flags;

 	if (flags & RV8803_FLAG_V1F)
 		dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");

 	if (flags & RV8803_FLAG_V2F)
 		dev_warn(&client->dev, "Voltage low, data loss detected.\n");

 	if (flags & RV8803_FLAG_AF)
 		dev_warn(&client->dev, "An alarm maybe have been missed.\n");

 	if (client->irq > 0) {
 		err = devm_request_threaded_irq(&client->dev, client->irq,
 						NULL, rv8803_handle_irq,
 						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 						"rv8803", client);
 		if (err) {
 			dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
 			client->irq = 0;
 		} else {
 			rv8803_rtc_ops.read_alarm = rv8803_get_alarm;
 			rv8803_rtc_ops.set_alarm = rv8803_set_alarm;
 			rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable;
 		}
 	}

 	rv8803->rtc = devm_rtc_device_register(&client->dev, client->name,
 					       &rv8803_rtc_ops, THIS_MODULE);
 	if (IS_ERR(rv8803->rtc)) {
 		dev_err(&client->dev, "unable to register the class device\n");
 		return PTR_ERR(rv8803->rtc);
 	}

 	try = 0;
 	do {
 		err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
 						RV8803_EXT_WADA);
 		try++;
 	} while ((err == -ENXIO) && (try < 3));
 	if (err)
 		return err;

 	err = device_create_bin_file(&client->dev, &rv8803_nvram_attr);
 	if (err)
 		return err;

 	rv8803->rtc->max_user_freq = 1;

 	return 0;
 }

 static int rv8803_remove(struct i2c_client *client)
 {
 	device_remove_bin_file(&client->dev, &rv8803_nvram_attr);

 	return 0;
 }

 static const struct i2c_device_id rv8803_id[] = {
 	{ "rv8803", 0 },
 	{ "rx8900", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, rv8803_id);

 static struct i2c_driver rv8803_driver = {
 	.driver = {
 		.name = "rtc-rv8803",
 	},
 	.probe		= rv8803_probe,
 	.remove		= rv8803_remove,
 	.id_table	= rv8803_id,
 };
 module_i2c_driver(rv8803_driver);

 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
 MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
 MODULE_LICENSE("GPL v2");
	/*
	* RTC driver for the Micro Crystal RV8803
	*
	* Copyright (C) 2015 Micro Crystal SA
	*
	* Alexandre Belloni <alexandre.belloni@free-electrons.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.
	*
	*/

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

	#define RV8803_SEC 0x00
	#define RV8803_MIN 0x01
	#define RV8803_HOUR 0x02
	#define RV8803_WEEK 0x03
	#define RV8803_DAY 0x04
	#define RV8803_MONTH 0x05
	#define RV8803_YEAR 0x06
	#define RV8803_RAM 0x07
	#define RV8803_ALARM_MIN 0x08
	#define RV8803_ALARM_HOUR 0x09
	#define RV8803_ALARM_WEEK_OR_DAY 0x0A
	#define RV8803_EXT 0x0D
	#define RV8803_FLAG 0x0E
	#define RV8803_CTRL 0x0F

	#define RV8803_EXT_WADA BIT(6)

	#define RV8803_FLAG_V1F BIT(0)
	#define RV8803_FLAG_V2F BIT(1)
	#define RV8803_FLAG_AF BIT(3)
	#define RV8803_FLAG_TF BIT(4)
	#define RV8803_FLAG_UF BIT(5)

	#define RV8803_CTRL_RESET BIT(0)

	#define RV8803_CTRL_EIE BIT(2)
	#define RV8803_CTRL_AIE BIT(3)
	#define RV8803_CTRL_TIE BIT(4)
	#define RV8803_CTRL_UIE BIT(5)

	struct rv8803_data {
	struct i2c_client *client;
	struct rtc_device *rtc;
	struct mutex flags_lock;
	u8 ctrl;
	};

	static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
	{
	struct i2c_client *client = dev_id;
	struct rv8803_data *rv8803 = i2c_get_clientdata(client);
	unsigned long events = 0;
	int flags, try = 0;

	mutex_lock(&rv8803->flags_lock);

	do {
	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
	try++;
	} while ((flags == -ENXIO) && (try < 3));
	if (flags <= 0) {
	mutex_unlock(&rv8803->flags_lock);
	return IRQ_NONE;
	}

	if (flags & RV8803_FLAG_V1F)
	dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");

	if (flags & RV8803_FLAG_V2F)
	dev_warn(&client->dev, "Voltage low, data loss detected.\n");

	if (flags & RV8803_FLAG_TF) {
	flags &= ~RV8803_FLAG_TF;
	rv8803->ctrl &= ~RV8803_CTRL_TIE;
	events \|= RTC_PF;
	}

	if (flags & RV8803_FLAG_AF) {
	flags &= ~RV8803_FLAG_AF;
	rv8803->ctrl &= ~RV8803_CTRL_AIE;
	events \|= RTC_AF;
	}

	if (flags & RV8803_FLAG_UF) {
	flags &= ~RV8803_FLAG_UF;
	rv8803->ctrl &= ~RV8803_CTRL_UIE;
	events \|= RTC_UF;
	}

	if (events) {
	rtc_update_irq(rv8803->rtc, 1, events);
	i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
	i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
	rv8803->ctrl);
	}

	mutex_unlock(&rv8803->flags_lock);

	return IRQ_HANDLED;
	}

	static int rv8803_get_time(struct device dev, struct rtc_time tm)
	{
	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
	u8 date1[7];
	u8 date2[7];
	u8 *date = date1;
	int ret, flags;

	flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
	if (flags < 0)
	return flags;

	if (flags & RV8803_FLAG_V2F) {
	dev_warn(dev, "Voltage low, data is invalid.\n");
	return -EINVAL;
	}

	ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
	7, date);
	if (ret != 7)
	return ret < 0 ? ret : -EIO;

	if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
	ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
	7, date2);
	if (ret != 7)
	return ret < 0 ? ret : -EIO;

	if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
	date = date2;
	}

	tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f);
	tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f);
	tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
	tm->tm_wday = ffs(date[RV8803_WEEK] & 0x7f);
	tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
	tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
	tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;

	return rtc_valid_tm(tm);
	}

	static int rv8803_set_time(struct device dev, struct rtc_time tm)
	{
	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
	u8 date[7];
	int flags, ret;

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

	date[RV8803_SEC] = bin2bcd(tm->tm_sec);
	date[RV8803_MIN] = bin2bcd(tm->tm_min);
	date[RV8803_HOUR] = bin2bcd(tm->tm_hour);
	date[RV8803_WEEK] = 1 << (tm->tm_wday);
	date[RV8803_DAY] = bin2bcd(tm->tm_mday);
	date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
	date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);

	ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC,
	7, date);
	if (ret < 0)
	return ret;

	mutex_lock(&rv8803->flags_lock);

	flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
	if (flags < 0) {
	mutex_unlock(&rv8803->flags_lock);
	return flags;
	}

	ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
	flags & ~RV8803_FLAG_V2F);

	mutex_unlock(&rv8803->flags_lock);

	return ret;
	}

	static int rv8803_get_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
	struct i2c_client *client = rv8803->client;
	u8 alarmvals[3];
	int flags, ret;

	ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN,
	3, alarmvals);
	if (ret != 3)
	return ret < 0 ? ret : -EIO;

	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
	if (flags < 0)
	return flags;

	alrm->time.tm_sec = 0;
	alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
	alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
	alrm->time.tm_wday = -1;
	alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
	alrm->time.tm_mon = -1;
	alrm->time.tm_year = -1;

	alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
	alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;

	return 0;
	}

	static int rv8803_set_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
	u8 alarmvals[3];
	u8 ctrl[2];
	int ret, err;

	/* The alarm has no seconds, round up to nearest minute */
	if (alrm->time.tm_sec) {
	time64_t alarm_time = rtc_tm_to_time64(&alrm->time);

	alarm_time += 60 - alrm->time.tm_sec;
	rtc_time64_to_tm(alarm_time, &alrm->time);
	}

	mutex_lock(&rv8803->flags_lock);

	ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
	if (ret != 2) {
	mutex_unlock(&rv8803->flags_lock);
	return ret < 0 ? ret : -EIO;
	}

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

	if (rv8803->ctrl & (RV8803_CTRL_AIE \| RV8803_CTRL_UIE)) {
	rv8803->ctrl &= ~(RV8803_CTRL_AIE \| RV8803_CTRL_UIE);
	err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
	rv8803->ctrl);
	if (err) {
	mutex_unlock(&rv8803->flags_lock);
	return err;
	}
	}

	ctrl[1] &= ~RV8803_FLAG_AF;
	err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
	mutex_unlock(&rv8803->flags_lock);
	if (err)
	return err;

	err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN,
	3, alarmvals);
	if (err)
	return err;

	if (alrm->enabled) {
	if (rv8803->rtc->uie_rtctimer.enabled)
	rv8803->ctrl \|= RV8803_CTRL_UIE;
	if (rv8803->rtc->aie_timer.enabled)
	rv8803->ctrl \|= RV8803_CTRL_AIE;

	err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
	rv8803->ctrl);
	if (err)
	return err;
	}

	return 0;
	}

	static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
	int ctrl, flags, err;

	ctrl = rv8803->ctrl;

	if (enabled) {
	if (rv8803->rtc->uie_rtctimer.enabled)
	ctrl \|= RV8803_CTRL_UIE;
	if (rv8803->rtc->aie_timer.enabled)
	ctrl \|= RV8803_CTRL_AIE;
	} else {
	if (!rv8803->rtc->uie_rtctimer.enabled)
	ctrl &= ~RV8803_CTRL_UIE;
	if (!rv8803->rtc->aie_timer.enabled)
	ctrl &= ~RV8803_CTRL_AIE;
	}

	mutex_lock(&rv8803->flags_lock);
	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
	if (flags < 0) {
	mutex_unlock(&rv8803->flags_lock);
	return flags;
	}
	flags &= ~(RV8803_FLAG_AF \| RV8803_FLAG_UF);
	err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
	mutex_unlock(&rv8803->flags_lock);
	if (err)
	return err;

	if (ctrl != rv8803->ctrl) {
	rv8803->ctrl = ctrl;
	err = i2c_smbus_write_byte_data(client, RV8803_CTRL,
	rv8803->ctrl);
	if (err)
	return err;
	}

	return 0;
	}

	static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
	int flags, ret = 0;

	switch (cmd) {
	case RTC_VL_READ:
	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
	if (flags < 0)
	return flags;

	if (flags & RV8803_FLAG_V1F)
	dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");

	if (flags & RV8803_FLAG_V2F)
	dev_warn(&client->dev, "Voltage low, data loss detected.\n");

	flags &= RV8803_FLAG_V1F \| RV8803_FLAG_V2F;

	if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
	return -EFAULT;

	return 0;

	case RTC_VL_CLR:
	mutex_lock(&rv8803->flags_lock);
	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
	if (flags < 0) {
	mutex_unlock(&rv8803->flags_lock);
	return flags;
	}

	flags &= ~(RV8803_FLAG_V1F \| RV8803_FLAG_V2F);
	ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
	mutex_unlock(&rv8803->flags_lock);
	if (ret < 0)
	return ret;

	return 0;

	default:
	return -ENOIOCTLCMD;
	}
	}

	static ssize_t rv8803_nvram_write(struct file filp, struct kobject kobj,
	struct bin_attribute *attr,
	char *buf, loff_t off, size_t count)
	{
	struct device *dev = kobj_to_dev(kobj);
	struct i2c_client *client = to_i2c_client(dev);
	int ret;

	ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]);
	if (ret < 0)
	return ret;

	return 1;
	}

	static ssize_t rv8803_nvram_read(struct file filp, struct kobject kobj,
	struct bin_attribute *attr,
	char *buf, loff_t off, size_t count)
	{
	struct device *dev = kobj_to_dev(kobj);
	struct i2c_client *client = to_i2c_client(dev);
	int ret;

	ret = i2c_smbus_read_byte_data(client, RV8803_RAM);
	if (ret < 0)
	return ret;

	buf[0] = ret;

	return 1;
	}

	static struct bin_attribute rv8803_nvram_attr = {
	.attr = {
	.name = "nvram",
	.mode = S_IRUGO \| S_IWUSR,
	},
	.size = 1,
	.read = rv8803_nvram_read,
	.write = rv8803_nvram_write,
	};

	static struct rtc_class_ops rv8803_rtc_ops = {
	.read_time = rv8803_get_time,
	.set_time = rv8803_set_time,
	.ioctl = rv8803_ioctl,
	};

	static int rv8803_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
	struct rv8803_data *rv8803;
	int err, flags, try = 0;

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

	rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
	GFP_KERNEL);
	if (!rv8803)
	return -ENOMEM;

	mutex_init(&rv8803->flags_lock);
	rv8803->client = client;
	i2c_set_clientdata(client, rv8803);

	/*
	* There is a 60µs window where the RTC may not reply on the i2c bus in
	* that case, the transfer is not ACKed. In that case, ensure there are
	* multiple attempts.
	*/
	do {
	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
	try++;
	} while ((flags == -ENXIO) && (try < 3));

	if (flags < 0)
	return flags;

	if (flags & RV8803_FLAG_V1F)
	dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");

	if (flags & RV8803_FLAG_V2F)
	dev_warn(&client->dev, "Voltage low, data loss detected.\n");

	if (flags & RV8803_FLAG_AF)
	dev_warn(&client->dev, "An alarm maybe have been missed.\n");

	if (client->irq > 0) {
	err = devm_request_threaded_irq(&client->dev, client->irq,
	NULL, rv8803_handle_irq,
	IRQF_TRIGGER_LOW \| IRQF_ONESHOT,
	"rv8803", client);
	if (err) {
	dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
	client->irq = 0;
	} else {
	rv8803_rtc_ops.read_alarm = rv8803_get_alarm;
	rv8803_rtc_ops.set_alarm = rv8803_set_alarm;
	rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable;
	}
	}

	rv8803->rtc = devm_rtc_device_register(&client->dev, client->name,
	&rv8803_rtc_ops, THIS_MODULE);
	if (IS_ERR(rv8803->rtc)) {
	dev_err(&client->dev, "unable to register the class device\n");
	return PTR_ERR(rv8803->rtc);
	}

	try = 0;
	do {
	err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
	RV8803_EXT_WADA);
	try++;
	} while ((err == -ENXIO) && (try < 3));
	if (err)
	return err;

	err = device_create_bin_file(&client->dev, &rv8803_nvram_attr);
	if (err)
	return err;

	rv8803->rtc->max_user_freq = 1;

	return 0;
	}

	static int rv8803_remove(struct i2c_client *client)
	{
	device_remove_bin_file(&client->dev, &rv8803_nvram_attr);

	return 0;
	}

	static const struct i2c_device_id rv8803_id[] = {
	{ "rv8803", 0 },
	{ "rx8900", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, rv8803_id);

	static struct i2c_driver rv8803_driver = {
	.driver = {
	.name = "rtc-rv8803",
	},
	.probe = rv8803_probe,
	.remove = rv8803_remove,
	.id_table = rv8803_id,
	};
	module_i2c_driver(rv8803_driver);

	MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
	MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
	MODULE_LICENSE("GPL v2");