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Commit 617b26a0 authored by Raghavendra Ganiga's avatar Raghavendra Ganiga Committed by Linus Torvalds
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rtc: add support for maxim dallas rtc ds1347 



Add support for maxim dallas rtc ds1347

Signed-off-by: default avatarRaghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
Acked-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5ab9a52a

drivers/rtc/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -573,6 +573,18 @@ config RTC_DRV_DS1305 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-ds1305.



config RTC_DRV_DS1347

	tristate "Dallas/Maxim DS1347"

	help

	  If you say yes here you get support for the

	  Dallas/Maxim DS1347 chips.



	  This driver only supports the RTC feature, and not other chip

	  features such as alarms.



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

	  will be called rtc-ds1347.



config RTC_DRV_DS1390

	tristate "Dallas/Maxim DS1390/93/94"

	help

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ obj-$(CONFIG_RTC_DRV_DS1286) += rtc-ds1286.o 
obj-$(CONFIG_RTC_DRV_DS1302)	+= rtc-ds1302.o

obj-$(CONFIG_RTC_DRV_DS1305)	+= rtc-ds1305.o

obj-$(CONFIG_RTC_DRV_DS1307)	+= rtc-ds1307.o

obj-$(CONFIG_RTC_DRV_DS1347)	+= rtc-ds1347.o

obj-$(CONFIG_RTC_DRV_DS1374)	+= rtc-ds1374.o

obj-$(CONFIG_RTC_DRV_DS1390)	+= rtc-ds1390.o

obj-$(CONFIG_RTC_DRV_DS1511)	+= rtc-ds1511.o

drivers/rtc/rtc-ds1347.c

0 → 100644
+166 −0
Original line number Diff line number Diff line 
/* rtc-ds1347.c

 *

 * Driver for Dallas Semiconductor DS1347 Low Current, SPI Compatible

 * Real Time Clock

 *

 * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.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/init.h>

#include <linux/module.h>

#include <linux/device.h>

#include <linux/platform_device.h>

#include <linux/rtc.h>

#include <linux/spi/spi.h>

#include <linux/bcd.h>



/* Registers in ds1347 rtc */



#define DS1347_SECONDS_REG	0x01

#define DS1347_MINUTES_REG	0x03

#define DS1347_HOURS_REG	0x05

#define DS1347_DATE_REG		0x07

#define DS1347_MONTH_REG	0x09

#define DS1347_DAY_REG		0x0B

#define DS1347_YEAR_REG		0x0D

#define DS1347_CONTROL_REG	0x0F

#define DS1347_STATUS_REG	0x17

#define DS1347_CLOCK_BURST	0x3F



static int ds1347_read_reg(struct device *dev, unsigned char address,

				unsigned char *data)

{

	struct spi_device *spi = to_spi_device(dev);



	*data = address | 0x80;



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

}



static int ds1347_write_reg(struct device *dev, unsigned char address,

				unsigned char data)

{

	struct spi_device *spi = to_spi_device(dev);

	unsigned char buf[2];



	buf[0] = address & 0x7F;

	buf[1] = data;



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

}



static int ds1347_read_time(struct device *dev, struct rtc_time *dt)

{

	struct spi_device *spi = to_spi_device(dev);

	int err;

	unsigned char buf[8];



	buf[0] = DS1347_CLOCK_BURST | 0x80;



	err = spi_write_then_read(spi, buf, 1, buf, 8);

	if (err)

		return err;



	dt->tm_sec = bcd2bin(buf[0]);

	dt->tm_min = bcd2bin(buf[1]);

	dt->tm_hour = bcd2bin(buf[2] & 0x3F);

	dt->tm_mday = bcd2bin(buf[3]);

	dt->tm_mon = bcd2bin(buf[4]) - 1;

	dt->tm_wday = bcd2bin(buf[5]) - 1;

	dt->tm_year = bcd2bin(buf[6]) + 100;



	return rtc_valid_tm(dt);

}



static int ds1347_set_time(struct device *dev, struct rtc_time *dt)

{

	struct spi_device *spi = to_spi_device(dev);

	unsigned char buf[9];



	buf[0] = DS1347_CLOCK_BURST & 0x7F;

	buf[1] = bin2bcd(dt->tm_sec);

	buf[2] = bin2bcd(dt->tm_min);

	buf[3] = (bin2bcd(dt->tm_hour) & 0x3F);

	buf[4] = bin2bcd(dt->tm_mday);

	buf[5] = bin2bcd(dt->tm_mon + 1);

	buf[6] = bin2bcd(dt->tm_wday + 1);



	/* year in linux is from 1900 i.e in range of 100

	in rtc it is from 00 to 99 */

	dt->tm_year = dt->tm_year % 100;



	buf[7] = bin2bcd(dt->tm_year);

	buf[8] = bin2bcd(0x00);



	/* write the rtc settings */

	return spi_write_then_read(spi, buf, 9, NULL, 0);

}



static const struct rtc_class_ops ds1347_rtc_ops = {

	.read_time = ds1347_read_time,

	.set_time = ds1347_set_time,

};



static int ds1347_probe(struct spi_device *spi)

{

	struct rtc_device *rtc;

	unsigned char data;

	int res;



	/* spi setup with ds1347 in mode 3 and bits per word as 8 */

	spi->mode = SPI_MODE_3;

	spi->bits_per_word = 8;

	spi_setup(spi);



	/* RTC Settings */

	res = ds1347_read_reg(&spi->dev, DS1347_SECONDS_REG, &data);

	if (res)

		return res;



	/* Disable the write protect of rtc */

	ds1347_read_reg(&spi->dev, DS1347_CONTROL_REG, &data);

	data = data & ~(1<<7);

	ds1347_write_reg(&spi->dev, DS1347_CONTROL_REG, data);



	/* Enable the oscillator , disable the oscillator stop flag,

	 and glitch filter to reduce current consumption */

	ds1347_read_reg(&spi->dev, DS1347_STATUS_REG, &data);

	data = data & 0x1B;

	ds1347_write_reg(&spi->dev, DS1347_STATUS_REG, data);



	/* display the settings */

	ds1347_read_reg(&spi->dev, DS1347_CONTROL_REG, &data);

	dev_info(&spi->dev, "DS1347 RTC CTRL Reg = 0x%02x\n", data);



	ds1347_read_reg(&spi->dev, DS1347_STATUS_REG, &data);

	dev_info(&spi->dev, "DS1347 RTC Status Reg = 0x%02x\n", data);



	rtc = devm_rtc_device_register(&spi->dev, "ds1347",

				&ds1347_rtc_ops, THIS_MODULE);



	if (IS_ERR(rtc))

		return PTR_ERR(rtc);



	spi_set_drvdata(spi, rtc);



	return 0;

}



static struct spi_driver ds1347_driver = {

	.driver = {

		.name = "ds1347",

		.owner = THIS_MODULE,

	},

	.probe = ds1347_probe,

};



module_spi_driver(ds1347_driver);



MODULE_DESCRIPTION("DS1347 SPI RTC DRIVER");

MODULE_AUTHOR("Raghavendra C Ganiga <ravi23ganiga@gmail.com>");

MODULE_LICENSE("GPL v2");