Commit 739d340d authored by Paul Mundt's avatar Paul Mundt Committed by Linus Torvalds
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rtc: ds1302 rtc support 



This adds a basic ds1302 RTC driver, which is basically a cleanup and move
of the in-tree SH SecureEdge5410 code (which is currently located in
arch/sh/board/snapgear/rtc.c) to drivers/rtc.

This aims to be a building block that the M32R and CRIS code can be worked
on top of, so we can get rid of drivers/char/ds1302.c and
arch/cris/arch-v10/drivers/ds1302.c respectively, though more work is
needed for this.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
Signed-off-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 e07e232c

drivers/rtc/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -306,6 +306,12 @@ config RTC_DRV_DS1216 
	help

	  If you say yes here you get support for the Dallas DS1216 RTC chips.



config RTC_DRV_DS1302

	tristate "Dallas DS1302"

	depends on SH_SECUREEDGE5410

	help

	  If you say yes here you get support for the Dallas DS1302 RTC chips.



config RTC_DRV_DS1553

	tristate "Maxim/Dallas DS1553"

	help

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o 
obj-$(CONFIG_RTC_DRV_BFIN)	+= rtc-bfin.o

obj-$(CONFIG_RTC_DRV_CMOS)	+= rtc-cmos.o

obj-$(CONFIG_RTC_DRV_DS1216)	+= rtc-ds1216.o

obj-$(CONFIG_RTC_DRV_DS1302)	+= rtc-ds1302.o

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

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

obj-$(CONFIG_RTC_DRV_DS1553)	+= rtc-ds1553.o

drivers/rtc/rtc-ds1302.c

0 → 100644
+262 −0
Original line number Diff line number Diff line 
/*

 * Dallas DS1302 RTC Support

 *

 *  Copyright (C) 2002  David McCullough

 *  Copyright (C) 2003 - 2007  Paul Mundt

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License version 2.  See the file "COPYING" in the main directory of

 * this archive for more details.

 */

#include <linux/init.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/platform_device.h>

#include <linux/time.h>

#include <linux/rtc.h>

#include <linux/spinlock.h>

#include <linux/io.h>

#include <linux/bcd.h>

#include <asm/rtc.h>



#define DRV_NAME	"rtc-ds1302"

#define DRV_VERSION	"0.1.0"



#define	RTC_CMD_READ	0x81		/* Read command */

#define	RTC_CMD_WRITE	0x80		/* Write command */



#define RTC_ADDR_RAM0	0x20		/* Address of RAM0 */

#define RTC_ADDR_TCR	0x08		/* Address of trickle charge register */

#define	RTC_ADDR_YEAR	0x06		/* Address of year register */

#define	RTC_ADDR_DAY	0x05		/* Address of day of week register */

#define	RTC_ADDR_MON	0x04		/* Address of month register */

#define	RTC_ADDR_DATE	0x03		/* Address of day of month register */

#define	RTC_ADDR_HOUR	0x02		/* Address of hour register */

#define	RTC_ADDR_MIN	0x01		/* Address of minute register */

#define	RTC_ADDR_SEC	0x00		/* Address of second register */



#define	RTC_RESET	0x1000

#define	RTC_IODATA	0x0800

#define	RTC_SCLK	0x0400



#ifdef CONFIG_SH_SECUREEDGE5410

#include <asm/snapgear.h>

#define set_dp(x)	SECUREEDGE_WRITE_IOPORT(x, 0x1c00)

#define get_dp()	SECUREEDGE_READ_IOPORT()

#else

#error "Add support for your platform"

#endif



struct ds1302_rtc {

	struct rtc_device *rtc_dev;

	spinlock_t lock;

};



static void ds1302_sendbits(unsigned int val)

{

	int i;



	for (i = 8; (i); i--, val >>= 1) {

		set_dp((get_dp() & ~RTC_IODATA) | ((val & 0x1) ?

			RTC_IODATA : 0));

		set_dp(get_dp() | RTC_SCLK);	/* clock high */

		set_dp(get_dp() & ~RTC_SCLK);	/* clock low */

	}

}



static unsigned int ds1302_recvbits(void)

{

	unsigned int val;

	int i;



	for (i = 0, val = 0; (i < 8); i++) {

		val |= (((get_dp() & RTC_IODATA) ? 1 : 0) << i);

		set_dp(get_dp() | RTC_SCLK);	/* clock high */

		set_dp(get_dp() & ~RTC_SCLK);	/* clock low */

	}



	return val;

}



static unsigned int ds1302_readbyte(unsigned int addr)

{

	unsigned int val;



	set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));



	set_dp(get_dp() | RTC_RESET);

	ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ);

	val = ds1302_recvbits();

	set_dp(get_dp() & ~RTC_RESET);



	return val;

}



static void ds1302_writebyte(unsigned int addr, unsigned int val)

{

	set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));

	set_dp(get_dp() | RTC_RESET);

	ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE);

	ds1302_sendbits(val);

	set_dp(get_dp() & ~RTC_RESET);

}



static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	struct ds1302_rtc *rtc = dev_get_drvdata(dev);



	spin_lock_irq(&rtc->lock);



	tm->tm_sec	= BCD2BIN(ds1302_readbyte(RTC_ADDR_SEC));

	tm->tm_min	= BCD2BIN(ds1302_readbyte(RTC_ADDR_MIN));

	tm->tm_hour	= BCD2BIN(ds1302_readbyte(RTC_ADDR_HOUR));

	tm->tm_wday	= BCD2BIN(ds1302_readbyte(RTC_ADDR_DAY));

	tm->tm_mday	= BCD2BIN(ds1302_readbyte(RTC_ADDR_DATE));

	tm->tm_mon	= BCD2BIN(ds1302_readbyte(RTC_ADDR_MON)) - 1;

	tm->tm_year	= BCD2BIN(ds1302_readbyte(RTC_ADDR_YEAR));



	if (tm->tm_year < 70)

		tm->tm_year += 100;



	spin_unlock_irq(&rtc->lock);



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

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

		__FUNCTION__,

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

		tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday);



	if (rtc_valid_tm(tm) < 0)

		dev_err(dev, "invalid date\n");



	return 0;

}



static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	struct ds1302_rtc *rtc = dev_get_drvdata(dev);



	spin_lock_irq(&rtc->lock);



	/* Stop RTC */

	ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80);



	ds1302_writebyte(RTC_ADDR_SEC, BIN2BCD(tm->tm_sec));

	ds1302_writebyte(RTC_ADDR_MIN, BIN2BCD(tm->tm_min));

	ds1302_writebyte(RTC_ADDR_HOUR, BIN2BCD(tm->tm_hour));

	ds1302_writebyte(RTC_ADDR_DAY, BIN2BCD(tm->tm_wday));

	ds1302_writebyte(RTC_ADDR_DATE, BIN2BCD(tm->tm_mday));

	ds1302_writebyte(RTC_ADDR_MON, BIN2BCD(tm->tm_mon + 1));

	ds1302_writebyte(RTC_ADDR_YEAR, BIN2BCD(tm->tm_year % 100));



	/* Start RTC */

	ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80);



	spin_unlock_irq(&rtc->lock);



	return 0;

}



static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd,

			    unsigned long arg)

{

	switch (cmd) {

#ifdef RTC_SET_CHARGE

	case RTC_SET_CHARGE:

	{

		struct ds1302_rtc *rtc = dev_get_drvdata(dev);

		int tcs_val;



		if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int)))

			return -EFAULT;



		spin_lock_irq(&rtc->lock);

		ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf));

		spin_unlock_irq(&rtc->lock);

		return 0;

	}

#endif

	}



	return -ENOIOCTLCMD;

}



static struct rtc_class_ops ds1302_rtc_ops = {

	.read_time	= ds1302_rtc_read_time,

	.set_time	= ds1302_rtc_set_time,

	.ioctl		= ds1302_rtc_ioctl,

};



static int __devinit ds1302_rtc_probe(struct platform_device *pdev)

{

	struct ds1302_rtc *rtc;

	int ret;



	/* Reset */

	set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));



	/* Write a magic value to the DS1302 RAM, and see if it sticks. */

	ds1302_writebyte(RTC_ADDR_RAM0, 0x42);

	if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42)

		return -ENODEV;



	rtc = kzalloc(sizeof(struct ds1302_rtc), GFP_KERNEL);

	if (unlikely(!rtc))

		return -ENOMEM;



	spin_lock_init(&rtc->lock);

	rtc->rtc_dev = rtc_device_register("ds1302", &pdev->dev,

					   &ds1302_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc->rtc_dev)) {

		ret = PTR_ERR(rtc->rtc_dev);

		goto out;

	}



	platform_set_drvdata(pdev, rtc);



	return 0;

out:

	kfree(rtc);

	return ret;

}



static int __devexit ds1302_rtc_remove(struct platform_device *pdev)

{

	struct ds1302_rtc *rtc = platform_get_drvdata(pdev);



	if (likely(rtc->rtc_dev))

		rtc_device_unregister(rtc->rtc_dev);



	platform_set_drvdata(pdev, NULL);



	kfree(rtc);



	return 0;

}



static struct platform_driver ds1302_platform_driver = {

	.driver		= {

		.name	= DRV_NAME,

		.owner	= THIS_MODULE,

	},

	.probe		= ds1302_rtc_probe,

	.remove		= __devexit_p(ds1302_rtc_remove),

};



static int __init ds1302_rtc_init(void)

{

	return platform_driver_register(&ds1302_platform_driver);

}



static void __exit ds1302_rtc_exit(void)

{

	platform_driver_unregister(&ds1302_platform_driver);

}



module_init(ds1302_rtc_init);

module_exit(ds1302_rtc_exit);



MODULE_DESCRIPTION("Dallas DS1302 RTC driver");

MODULE_VERSION(DRV_VERSION);

MODULE_AUTHOR("Paul Mundt, David McCullough");

MODULE_LICENSE("GPL v2");

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