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Commit cce2da9a authored by Torben Hohn's avatar Torben Hohn Committed by Linus Torvalds
Browse files

rtc: add support for spi rtc rx4581 



[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: default avatarTorben Hohn <torbenh@linutronix.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 225ccc28

drivers/rtc/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -561,6 +561,14 @@ config RTC_DRV_PCF2123 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-pcf2123.



config RTC_DRV_RX4581

	tristate "Epson RX-4581"

	help

	  If you say yes here you will get support for the Epson RX-4581.



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

	  will be called rtc-rx4581.



endif # SPI_MASTER



comment "Platform RTC drivers"

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -98,6 +98,7 @@ 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_RX4581)	+= rtc-rx4581.o

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

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

obj-$(CONFIG_RTC_DRV_S35390A)	+= rtc-s35390a.o

drivers/rtc/rtc-rx4581.c

0 → 100644
+314 −0
Original line number Diff line number Diff line 
/* drivers/rtc/rtc-rx4581.c

 *

 * written by Torben Hohn <torbenh@linutronix.de>

 *

 * Based on:

 * drivers/rtc/rtc-max6902.c

 *

 * Copyright (C) 2006 8D Technologies inc.

 * Copyright (C) 2004 Compulab Ltd.

 *

 * 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.

 *

 * Driver for MAX6902 spi RTC

 *

 * and based on:

 * drivers/rtc/rtc-rx8581.c

 *

 * An I2C driver for the Epson RX8581 RTC

 *

 * Author: Martyn Welch <martyn.welch@ge.com>

 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.

 *

 * 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.

 *

 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)

 * Copyright 2005-06 Tower Technologies

 *

 */



#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/platform_device.h>

#include <linux/init.h>

#include <linux/rtc.h>

#include <linux/spi/spi.h>

#include <linux/bcd.h>



#define RX4581_REG_SC		0x00 /* Second in BCD */

#define RX4581_REG_MN		0x01 /* Minute in BCD */

#define RX4581_REG_HR		0x02 /* Hour in BCD */

#define RX4581_REG_DW		0x03 /* Day of Week */

#define RX4581_REG_DM		0x04 /* Day of Month in BCD */

#define RX4581_REG_MO		0x05 /* Month in BCD */

#define RX4581_REG_YR		0x06 /* Year in BCD */

#define RX4581_REG_RAM		0x07 /* RAM */

#define RX4581_REG_AMN		0x08 /* Alarm Min in BCD*/

#define RX4581_REG_AHR		0x09 /* Alarm Hour in BCD */

#define RX4581_REG_ADM		0x0A

#define RX4581_REG_ADW		0x0A

#define RX4581_REG_TMR0		0x0B

#define RX4581_REG_TMR1		0x0C

#define RX4581_REG_EXT		0x0D /* Extension Register */

#define RX4581_REG_FLAG		0x0E /* Flag Register */

#define RX4581_REG_CTRL		0x0F /* Control Register */





/* Flag Register bit definitions */

#define RX4581_FLAG_UF		0x20 /* Update */

#define RX4581_FLAG_TF		0x10 /* Timer */

#define RX4581_FLAG_AF		0x08 /* Alarm */

#define RX4581_FLAG_VLF		0x02 /* Voltage Low */



/* Control Register bit definitions */

#define RX4581_CTRL_UIE		0x20 /* Update Interrupt Enable */

#define RX4581_CTRL_TIE		0x10 /* Timer Interrupt Enable */

#define RX4581_CTRL_AIE		0x08 /* Alarm Interrupt Enable */

#define RX4581_CTRL_STOP	0x02 /* STOP bit */

#define RX4581_CTRL_RESET	0x01 /* RESET bit */



static int rx4581_set_reg(struct device *dev, unsigned char address,

				unsigned char data)

{

	struct spi_device *spi = to_spi_device(dev);

	unsigned char buf[2];



	/* high nibble must be '0' to write */

	buf[0] = address & 0x0f;

	buf[1] = data;



	return spi_write_then_read(spi, buf, 2, NULL, 0);

}



static int rx4581_get_reg(struct device *dev, unsigned char address,

				unsigned char *data)

{

	struct spi_device *spi = to_spi_device(dev);



	/* Set MSB to indicate read */

	*data = address | 0x80;



	return spi_write_then_read(spi, data, 1, data, 1);

}



/*

 * In the routines that deal directly with the rx8581 hardware, we use

 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.

 */

static int rx4581_get_datetime(struct device *dev, struct rtc_time *tm)

{

	struct spi_device *spi = to_spi_device(dev);

	unsigned char date[7];

	unsigned char data;

	int err;



	/* First we ensure that the "update flag" is not set, we read the

	 * time and date then re-read the "update flag". If the update flag

	 * has been set, we know that the time has changed during the read so

	 * we repeat the whole process again.

	 */

	err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);

	if (err != 0) {

		dev_err(dev, "Unable to read device flags\n");

		return -EIO;

	}



	do {

		/* If update flag set, clear it */

		if (data & RX4581_FLAG_UF) {

			err = rx4581_set_reg(dev,

				RX4581_REG_FLAG, (data & ~RX4581_FLAG_UF));

			if (err != 0) {

				dev_err(dev, "Unable to write device "

					"flags\n");

				return -EIO;

			}

		}



		/* Now read time and date */

		date[0] = 0x80;

		err = spi_write_then_read(spi, date, 1, date, 7);

		if (err < 0) {

			dev_err(dev, "Unable to read date\n");

			return -EIO;

		}



		/* Check flag register */

		err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);

		if (err != 0) {

			dev_err(dev, "Unable to read device flags\n");

			return -EIO;

		}

	} while (data & RX4581_FLAG_UF);



	if (data & RX4581_FLAG_VLF)

		dev_info(dev,

			"low voltage detected, date/time is not reliable.\n");



	dev_dbg(dev,

		"%s: raw data is sec=%02x, min=%02x, hr=%02x, "

		"wday=%02x, mday=%02x, mon=%02x, year=%02x\n",

		__func__,

		date[0], date[1], date[2], date[3], date[4], date[5], date[6]);



	tm->tm_sec = bcd2bin(date[RX4581_REG_SC] & 0x7F);

	tm->tm_min = bcd2bin(date[RX4581_REG_MN] & 0x7F);

	tm->tm_hour = bcd2bin(date[RX4581_REG_HR] & 0x3F); /* rtc hr 0-23 */

	tm->tm_wday = ilog2(date[RX4581_REG_DW] & 0x7F);

	tm->tm_mday = bcd2bin(date[RX4581_REG_DM] & 0x3F);

	tm->tm_mon = bcd2bin(date[RX4581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */

	tm->tm_year = bcd2bin(date[RX4581_REG_YR]);

	if (tm->tm_year < 70)

		tm->tm_year += 100;	/* assume we are in 1970...2069 */





	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "

		"mday=%d, mon=%d, year=%d, wday=%d\n",

		__func__,

		tm->tm_sec, tm->tm_min, tm->tm_hour,

		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);



	err = rtc_valid_tm(tm);

	if (err < 0)

		dev_err(dev, "retrieved date/time is not valid.\n");



	return err;

}



static int rx4581_set_datetime(struct device *dev, struct rtc_time *tm)

{

	struct spi_device *spi = to_spi_device(dev);

	int err;

	unsigned char buf[8], data;



	dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "

		"mday=%d, mon=%d, year=%d, wday=%d\n",

		__func__,

		tm->tm_sec, tm->tm_min, tm->tm_hour,

		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);



	buf[0] = 0x00;

	/* hours, minutes and seconds */

	buf[RX4581_REG_SC+1] = bin2bcd(tm->tm_sec);

	buf[RX4581_REG_MN+1] = bin2bcd(tm->tm_min);

	buf[RX4581_REG_HR+1] = bin2bcd(tm->tm_hour);



	buf[RX4581_REG_DM+1] = bin2bcd(tm->tm_mday);



	/* month, 1 - 12 */

	buf[RX4581_REG_MO+1] = bin2bcd(tm->tm_mon + 1);



	/* year and century */

	buf[RX4581_REG_YR+1] = bin2bcd(tm->tm_year % 100);

	buf[RX4581_REG_DW+1] = (0x1 << tm->tm_wday);



	/* Stop the clock */

	err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data);

	if (err != 0) {

		dev_err(dev, "Unable to read control register\n");

		return -EIO;

	}



	err = rx4581_set_reg(dev, RX4581_REG_CTRL,

		(data | RX4581_CTRL_STOP));

	if (err != 0) {

		dev_err(dev, "Unable to write control register\n");

		return -EIO;

	}



	/* write register's data */

	err = spi_write_then_read(spi, buf, 8, NULL, 0);

	if (err != 0) {

		dev_err(dev, "Unable to write to date registers\n");

		return -EIO;

	}



	/* get VLF and clear it */

	err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);

	if (err != 0) {

		dev_err(dev, "Unable to read flag register\n");

		return -EIO;

	}



	err = rx4581_set_reg(dev, RX4581_REG_FLAG,

		(data & ~(RX4581_FLAG_VLF)));

	if (err != 0) {

		dev_err(dev, "Unable to write flag register\n");

		return -EIO;

	}



	/* Restart the clock */

	err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data);

	if (err != 0) {

		dev_err(dev, "Unable to read control register\n");

		return -EIO;

	}



	err = rx4581_set_reg(dev, RX4581_REG_CTRL,

		(data & ~(RX4581_CTRL_STOP)));

	if (err != 0) {

		dev_err(dev, "Unable to write control register\n");

		return -EIO;

	}



	return 0;

}



static const struct rtc_class_ops rx4581_rtc_ops = {

	.read_time	= rx4581_get_datetime,

	.set_time	= rx4581_set_datetime,

};



static int rx4581_probe(struct spi_device *spi)

{

	struct rtc_device *rtc;

	unsigned char tmp;

	int res;



	res = rx4581_get_reg(&spi->dev, RX4581_REG_SC, &tmp);

	if (res != 0)

		return res;



	rtc = rtc_device_register("rx4581",

				&spi->dev, &rx4581_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc))

		return PTR_ERR(rtc);



	dev_set_drvdata(&spi->dev, rtc);

	return 0;

}



static int rx4581_remove(struct spi_device *spi)

{

	struct rtc_device *rtc = dev_get_drvdata(&spi->dev);



	rtc_device_unregister(rtc);

	return 0;

}



static const struct spi_device_id rx4581_id[] = {

	{ "rx4581", 0 },

	{ }

};

MODULE_DEVICE_TABLE(spi, rx4581_id);



static struct spi_driver rx4581_driver = {

	.driver = {

		.name	= "rtc-rx4581",

		.owner	= THIS_MODULE,

	},

	.probe	= rx4581_probe,

	.remove = rx4581_remove,

	.id_table = rx4581_id,

};



module_spi_driver(rx4581_driver);



MODULE_DESCRIPTION("rx4581 spi RTC driver");

MODULE_AUTHOR("Torben Hohn");

MODULE_LICENSE("GPL");

MODULE_ALIAS("spi:rtc-rx4581");