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Commit 1e3929ef authored by Alexandre Belloni's avatar Alexandre Belloni
Browse files

rtc: Add a driver for Micro Crystal RV8803 



This driver supports the following functions:
 - reading and settings time
 - alarms when connected to an IRQ
 - reading and clearing the voltage low flags
 - nvram

Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent fb4ac3c1

drivers/rtc/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -593,6 +593,15 @@ config RTC_DRV_RV3029C2 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-rv3029c2.



config RTC_DRV_RV8803

	tristate "Micro Crystal RV8803"

	help

	  If you say yes here you get support for the Micro Crystal

	  RV8803 RTC chips.



	  This driver can also be built as a module. If so, the module

	  will be called rtc-rv8803.



config RTC_DRV_S5M

	tristate "Samsung S2M/S5M series"

	depends on MFD_SEC_CORE

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ obj-$(CONFIG_RTC_DRV_RS5C313) += rtc-rs5c313.o 
obj-$(CONFIG_RTC_DRV_RS5C348)	+= rtc-rs5c348.o

obj-$(CONFIG_RTC_DRV_RS5C372)	+= rtc-rs5c372.o

obj-$(CONFIG_RTC_DRV_RV3029C2)	+= rtc-rv3029c2.o

obj-$(CONFIG_RTC_DRV_RV8803)	+= rtc-rv8803.o

obj-$(CONFIG_RTC_DRV_RX4581)	+= rtc-rx4581.o

obj-$(CONFIG_RTC_DRV_RX8025)	+= rtc-rx8025.o

obj-$(CONFIG_RTC_DRV_RX8581)	+= rtc-rx8581.o

drivers/rtc/rtc-rv8803.c

0 → 100644
+521 −0
Original line number Diff line number Diff line 
/*

 * 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;

	spinlock_t 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;

	u8 flags;



	spin_lock(&rv8803->flags_lock);



	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);

	if (flags <= 0) {

		spin_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);

	}



	spin_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;

	unsigned long irqflags;



	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;



	spin_lock_irqsave(&rv8803->flags_lock, irqflags);



	flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);

	if (flags < 0) {

		spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);

		return flags;

	}



	ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,

					flags & ~RV8803_FLAG_V2F);



	spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);



	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;

	unsigned long irqflags;



	/* 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);

	}



	spin_lock_irqsave(&rv8803->flags_lock, irqflags);



	ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);

	if (ret != 2) {

		spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);

		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) {

			spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);

			return err;

		}

	}



	ctrl[1] &= ~RV8803_FLAG_AF;

	err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);

	spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);

	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;

	unsigned long irqflags;



	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;

	}



	spin_lock_irqsave(&rv8803->flags_lock, irqflags);

	flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);

	if (flags < 0) {

		spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);

		return flags;

	}

	flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);

	err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);

	spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);

	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;

	unsigned long irqflags;



	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:

		spin_lock_irqsave(&rv8803->flags_lock, irqflags);

		flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);

		if (flags < 0) {

			spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);

			return flags;

		}



		flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);

		ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);

		spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);

		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;



	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;



	rv8803->client = client;

	i2c_set_clientdata(client, rv8803);



	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");



	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);

	}



	err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,

					RV8803_EXT_WADA);

	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 },

	{ }

};

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");