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Commit 5ec3e4b7 authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Linus Torvalds
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[PATCH] RTC: add rtc-ds1742 driver 



Add an RTC driver for the Dallas DS1742 RTC chip.

[akpm@osdl.org: cleanups, compile fix]
Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9bf5b4f5

drivers/rtc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -131,6 +131,16 @@ config RTC_DRV_DS1672 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-ds1672.



config RTC_DRV_DS1742

	tristate "Dallas DS1742"

	depends on RTC_CLASS

	help

	  If you say yes here you get support for the

	  Dallas DS1742 timekeeping chip.



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

	  will be called rtc-ds1742.



config RTC_DRV_PCF8563

	tristate "Philips PCF8563/Epson RTC8564"

	depends on RTC_CLASS && I2C

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ obj-$(CONFIG_RTC_DRV_X1205) += rtc-x1205.o 
obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o

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

obj-$(CONFIG_RTC_DRV_DS1672)	+= rtc-ds1672.o

obj-$(CONFIG_RTC_DRV_DS1742)	+= rtc-ds1742.o

obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o

obj-$(CONFIG_RTC_DRV_PCF8583)	+= rtc-pcf8583.o

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

drivers/rtc/rtc-ds1742.c

0 → 100644
+259 −0
Original line number Diff line number Diff line 
/*

 * An rtc driver for the Dallas DS1742

 *

 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>

 *

 * 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/init.h>

#include <linux/kernel.h>

#include <linux/delay.h>

#include <linux/jiffies.h>

#include <linux/rtc.h>

#include <linux/platform_device.h>

#include <linux/io.h>



#define DRV_VERSION "0.1"



#define RTC_REG_SIZE		0x800

#define RTC_OFFSET		0x7f8



#define RTC_CONTROL		(RTC_OFFSET + 0)

#define RTC_CENTURY		(RTC_OFFSET + 0)

#define RTC_SECONDS		(RTC_OFFSET + 1)

#define RTC_MINUTES		(RTC_OFFSET + 2)

#define RTC_HOURS		(RTC_OFFSET + 3)

#define RTC_DAY			(RTC_OFFSET + 4)

#define RTC_DATE		(RTC_OFFSET + 5)

#define RTC_MONTH		(RTC_OFFSET + 6)

#define RTC_YEAR		(RTC_OFFSET + 7)



#define RTC_CENTURY_MASK	0x3f

#define RTC_SECONDS_MASK	0x7f

#define RTC_DAY_MASK		0x07



/* Bits in the Control/Century register */

#define RTC_WRITE		0x80

#define RTC_READ		0x40



/* Bits in the Seconds register */

#define RTC_STOP		0x80



/* Bits in the Day register */

#define RTC_BATT_FLAG		0x80



struct rtc_plat_data {

	struct rtc_device *rtc;

	void __iomem *ioaddr;

	unsigned long baseaddr;

	unsigned long last_jiffies;

};



static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	struct platform_device *pdev = to_platform_device(dev);

	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	void __iomem *ioaddr = pdata->ioaddr;

	u8 century;



	century = BIN2BCD((tm->tm_year + 1900) / 100);



	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);



	writeb(BIN2BCD(tm->tm_year % 100), ioaddr + RTC_YEAR);

	writeb(BIN2BCD(tm->tm_mon + 1), ioaddr + RTC_MONTH);

	writeb(BIN2BCD(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);

	writeb(BIN2BCD(tm->tm_mday), ioaddr + RTC_DATE);

	writeb(BIN2BCD(tm->tm_hour), ioaddr + RTC_HOURS);

	writeb(BIN2BCD(tm->tm_min), ioaddr + RTC_MINUTES);

	writeb(BIN2BCD(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);



	/* RTC_CENTURY and RTC_CONTROL share same register */

	writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);

	writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);

	return 0;

}



static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	struct platform_device *pdev = to_platform_device(dev);

	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	void __iomem *ioaddr = pdata->ioaddr;

	unsigned int year, month, day, hour, minute, second, week;

	unsigned int century;



	/* give enough time to update RTC in case of continuous read */

	if (pdata->last_jiffies == jiffies)

		msleep(1);

	pdata->last_jiffies = jiffies;

	writeb(RTC_READ, ioaddr + RTC_CONTROL);

	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;

	minute = readb(ioaddr + RTC_MINUTES);

	hour = readb(ioaddr + RTC_HOURS);

	day = readb(ioaddr + RTC_DATE);

	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;

	month = readb(ioaddr + RTC_MONTH);

	year = readb(ioaddr + RTC_YEAR);

	century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;

	writeb(0, ioaddr + RTC_CONTROL);

	tm->tm_sec = BCD2BIN(second);

	tm->tm_min = BCD2BIN(minute);

	tm->tm_hour = BCD2BIN(hour);

	tm->tm_mday = BCD2BIN(day);

	tm->tm_wday = BCD2BIN(week);

	tm->tm_mon = BCD2BIN(month) - 1;

	/* year is 1900 + tm->tm_year */

	tm->tm_year = BCD2BIN(year) + BCD2BIN(century) * 100 - 1900;



	if (rtc_valid_tm(tm) < 0) {

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

		rtc_time_to_tm(0, tm);

	}

	return 0;

}



static struct rtc_class_ops ds1742_rtc_ops = {

	.read_time	= ds1742_rtc_read_time,

	.set_time	= ds1742_rtc_set_time,

};



static ssize_t ds1742_nvram_read(struct kobject *kobj, char *buf,

				 loff_t pos, size_t size)

{

	struct platform_device *pdev =

		to_platform_device(container_of(kobj, struct device, kobj));

	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	void __iomem *ioaddr = pdata->ioaddr;

	ssize_t count;



	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)

		*buf++ = readb(ioaddr + pos++);

	return count;

}



static ssize_t ds1742_nvram_write(struct kobject *kobj, char *buf,

				  loff_t pos, size_t size)

{

	struct platform_device *pdev =

		to_platform_device(container_of(kobj, struct device, kobj));

	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	void __iomem *ioaddr = pdata->ioaddr;

	ssize_t count;



	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)

		writeb(*buf++, ioaddr + pos++);

	return count;

}



static struct bin_attribute ds1742_nvram_attr = {

	.attr = {

		.name = "nvram",

		.mode = S_IRUGO | S_IWUGO,

		.owner = THIS_MODULE,

	},

	.size = RTC_OFFSET,

	.read = ds1742_nvram_read,

	.write = ds1742_nvram_write,

};



static int __init ds1742_rtc_probe(struct platform_device *pdev)

{

	struct rtc_device *rtc;

	struct resource *res;

	unsigned int cen, sec;

	struct rtc_plat_data *pdata = NULL;

	void __iomem *ioaddr = NULL;

	int ret = 0;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res)

		return -ENODEV;

	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);

	if (!pdata)

		return -ENOMEM;

	if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {

		ret = -EBUSY;

		goto out;

	}

	pdata->baseaddr = res->start;

	ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);

	if (!ioaddr) {

		ret = -ENOMEM;

		goto out;

	}

	pdata->ioaddr = ioaddr;



	/* turn RTC on if it was not on */

	sec = readb(ioaddr + RTC_SECONDS);

	if (sec & RTC_STOP) {

		sec &= RTC_SECONDS_MASK;

		cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;

		writeb(RTC_WRITE, ioaddr + RTC_CONTROL);

		writeb(sec, ioaddr + RTC_SECONDS);

		writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);

	}

	if (readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG)

		dev_warn(&pdev->dev, "voltage-low detected.\n");



	rtc = rtc_device_register(pdev->name, &pdev->dev,

				  &ds1742_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc)) {

		ret = PTR_ERR(rtc);

		goto out;

	}

	pdata->rtc = rtc;

	pdata->last_jiffies = jiffies;

	platform_set_drvdata(pdev, pdata);

	sysfs_create_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);

	return 0;

 out:

	if (ioaddr)

		iounmap(ioaddr);

	if (pdata->baseaddr)

		release_mem_region(pdata->baseaddr, RTC_REG_SIZE);

	kfree(pdata);

	return ret;

}



static int __devexit ds1742_rtc_remove(struct platform_device *pdev)

{

	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);



	sysfs_remove_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);

	rtc_device_unregister(pdata->rtc);

	iounmap(pdata->ioaddr);

	release_mem_region(pdata->baseaddr, RTC_REG_SIZE);

	kfree(pdata);

	return 0;

}



static struct platform_driver ds1742_rtc_driver = {

	.probe		= ds1742_rtc_probe,

	.remove		= __devexit_p(ds1742_rtc_remove),

	.driver		= {

		.name	= "ds1742",

		.owner	= THIS_MODULE,

	},

};



static __init int ds1742_init(void)

{

	return platform_driver_register(&ds1742_rtc_driver);

}



static __exit void ds1742_exit(void)

{

	return platform_driver_unregister(&ds1742_rtc_driver);

}



module_init(ds1742_init);

module_exit(ds1742_exit);



MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");

MODULE_DESCRIPTION("Dallas DS1742 RTC driver");

MODULE_LICENSE("GPL");

MODULE_VERSION(DRV_VERSION);