Commit 362600fe authored by Raphael Assenat's avatar Raphael Assenat Committed by Linus Torvalds
Browse files

[PATCH] Add v3020 RTC support 

This patch adds support for the v3020 RTC from EM Microelectronic.

The v3020 RTC is designed to be connected on a bus using only one data bit.
 Since any data bit may be used, it is necessary to specify this to the
driver by passing a struct v3020_platform_data pointer (see
include/linux/rtc-v3020.h) to the driver.

Part of the following code comes from the kernel patchs produced by
Compulab for their products.  The original file (available here:
http://raph.people.8d.com/misc/emv3020.c

) was released under the terms of
the GPL license.

[akpm@osdl.org: cleanups]
Signed-off-by: default avatarRaphael Assenat <raph@raphnet.net>
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 9be05b57

drivers/rtc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -227,4 +227,14 @@ config RTC_DRV_MAX6902 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-max6902.



config RTC_DRV_V3020

	tristate "EM Microelectronic V3020"

	depends on RTC_CLASS

	help

	  If you say yes here you will get support for the

	  EM Microelectronic v3020 RTC chip.



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

	  will be called rtc-v3020.



endmenu

drivers/rtc/Makefile

+1 −0
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@@ -24,3 +24,4 @@ obj-$(CONFIG_RTC_DRV_SA1100) += rtc-sa1100.o 
obj-$(CONFIG_RTC_DRV_VR41XX)	+= rtc-vr41xx.o

obj-$(CONFIG_RTC_DRV_PL031)	+= rtc-pl031.o

obj-$(CONFIG_RTC_DRV_MAX6902)	+= rtc-max6902.o

obj-$(CONFIG_RTC_DRV_V3020)	+= rtc-v3020.o

drivers/rtc/rtc-v3020.c

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Original line number Diff line number Diff line 
/* drivers/rtc/rtc-v3020.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 the V3020 RTC

 *

 * Changelog:

 *

 *  10-May-2006: Raphael Assenat <raph@8d.com>

 *				- Converted to platform driver

 *				- Use the generic rtc class

 *

 *  ??-???-2004: Someone at Compulab

 *  			- Initial driver creation.

 *

 */

#include <linux/platform_device.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/rtc.h>

#include <linux/types.h>

#include <linux/bcd.h>

#include <linux/rtc-v3020.h>



#include <asm/io.h>



#undef DEBUG



struct v3020 {

	void __iomem *ioaddress;

	int leftshift;

	struct rtc_device *rtc;

};



static void v3020_set_reg(struct v3020 *chip, unsigned char address,

			unsigned char data)

{

	int i;

	unsigned char tmp;



	tmp = address;

	for (i = 0; i < 4; i++) {

		writel((tmp & 1) << chip->leftshift, chip->ioaddress);

		tmp >>= 1;

	}



	/* Commands dont have data */

	if (!V3020_IS_COMMAND(address)) {

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

			writel((data & 1) << chip->leftshift, chip->ioaddress);

			data >>= 1;

		}

	}

}



static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)

{

	unsigned int data=0;

	int i;



	for (i = 0; i < 4; i++) {

		writel((address & 1) << chip->leftshift, chip->ioaddress);

		address >>= 1;

	}



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

		data >>= 1;

		if (readl(chip->ioaddress) & (1 << chip->leftshift))

			data |= 0x80;

	}



	return data;

}



static int v3020_read_time(struct device *dev, struct rtc_time *dt)

{

	struct v3020 *chip = dev_get_drvdata(dev);

	int tmp;



	/* Copy the current time to ram... */

	v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);



	/* ...and then read constant values. */

	tmp = v3020_get_reg(chip, V3020_SECONDS);

	dt->tm_sec	= BCD2BIN(tmp);

	tmp = v3020_get_reg(chip, V3020_MINUTES);

	dt->tm_min	= BCD2BIN(tmp);

	tmp = v3020_get_reg(chip, V3020_HOURS);

	dt->tm_hour	= BCD2BIN(tmp);

	tmp = v3020_get_reg(chip, V3020_MONTH_DAY);

	dt->tm_mday	= BCD2BIN(tmp);

	tmp = v3020_get_reg(chip, V3020_MONTH);

	dt->tm_mon	= BCD2BIN(tmp);

	tmp = v3020_get_reg(chip, V3020_WEEK_DAY);

	dt->tm_wday	= BCD2BIN(tmp);

	tmp = v3020_get_reg(chip, V3020_YEAR);

	dt->tm_year = BCD2BIN(tmp)+100;



#ifdef DEBUG

	printk("\n%s : Read RTC values\n",__FUNCTION__);

	printk("tm_hour: %i\n",dt->tm_hour);

	printk("tm_min : %i\n",dt->tm_min);

	printk("tm_sec : %i\n",dt->tm_sec);

	printk("tm_year: %i\n",dt->tm_year);

	printk("tm_mon : %i\n",dt->tm_mon);

	printk("tm_mday: %i\n",dt->tm_mday);

	printk("tm_wday: %i\n",dt->tm_wday);

#endif



	return 0;

}





static int v3020_set_time(struct device *dev, struct rtc_time *dt)

{

	struct v3020 *chip = dev_get_drvdata(dev);



#ifdef DEBUG

	printk("\n%s : Setting RTC values\n",__FUNCTION__);

	printk("tm_sec : %i\n",dt->tm_sec);

	printk("tm_min : %i\n",dt->tm_min);

	printk("tm_hour: %i\n",dt->tm_hour);

	printk("tm_mday: %i\n",dt->tm_mday);

	printk("tm_wday: %i\n",dt->tm_wday);

	printk("tm_year: %i\n",dt->tm_year);

#endif



	/* Write all the values to ram... */

	v3020_set_reg(chip, V3020_SECONDS, 	BIN2BCD(dt->tm_sec));

	v3020_set_reg(chip, V3020_MINUTES, 	BIN2BCD(dt->tm_min));

	v3020_set_reg(chip, V3020_HOURS, 	BIN2BCD(dt->tm_hour));

	v3020_set_reg(chip, V3020_MONTH_DAY,	BIN2BCD(dt->tm_mday));

	v3020_set_reg(chip, V3020_MONTH, 	BIN2BCD(dt->tm_mon));

	v3020_set_reg(chip, V3020_WEEK_DAY, 	BIN2BCD(dt->tm_wday));

	v3020_set_reg(chip, V3020_YEAR, 	BIN2BCD(dt->tm_year % 100));



	/* ...and set the clock. */

	v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);



	/* Compulab used this delay here. I dont know why,

	 * the datasheet does not specify a delay. */

	/*mdelay(5);*/



	return 0;

}



static struct rtc_class_ops v3020_rtc_ops = {

	.read_time	= v3020_read_time,

	.set_time	= v3020_set_time,

};



static int rtc_probe(struct platform_device *pdev)

{

	struct v3020_platform_data *pdata = pdev->dev.platform_data;

	struct v3020 *chip;

	struct rtc_device *rtc;

	int retval = -EBUSY;

	int i;

	int temp;



	if (pdev->num_resources != 1)

		return -EBUSY;



	if (pdev->resource[0].flags != IORESOURCE_MEM)

		return -EBUSY;



	if (pdev == NULL)

		return -EBUSY;



	chip = kzalloc(sizeof *chip, GFP_KERNEL);

	if (!chip)

		return -ENOMEM;



	chip->leftshift = pdata->leftshift;

	chip->ioaddress = ioremap(pdev->resource[0].start, 1);

	if (chip->ioaddress == NULL)

		goto err_chip;



	/* Make sure the v3020 expects a communication cycle

	 * by reading 8 times */

	for (i = 0; i < 8; i++)

		temp = readl(chip->ioaddress);



	/* Test chip by doing a write/read sequence

	 * to the chip ram */

	v3020_set_reg(chip, V3020_SECONDS, 0x33);

	if(v3020_get_reg(chip, V3020_SECONDS) != 0x33) {

		retval = -ENODEV;

		goto err_io;

	}



	/* Make sure frequency measurment mode, test modes, and lock

	 * are all disabled */

	v3020_set_reg(chip, V3020_STATUS_0, 0x0);



	dev_info(&pdev->dev, "Chip available at physical address 0x%p,"

		"data connected to D%d\n",

		(void*)pdev->resource[0].start,

		chip->leftshift);



	platform_set_drvdata(pdev, chip);



	rtc = rtc_device_register("v3020",

				&pdev->dev, &v3020_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc)) {

		retval = PTR_ERR(rtc);

		goto err_io;

	}

	chip->rtc = rtc;



	return 0;



err_io:

	iounmap(chip->ioaddress);

err_chip:

	kfree(chip);



	return retval;

}



static int rtc_remove(struct platform_device *dev)

{

	struct v3020 *chip = platform_get_drvdata(dev);

	struct rtc_device *rtc = chip->rtc;



	if (rtc)

		rtc_device_unregister(rtc);



	iounmap(chip->ioaddress);

	kfree(chip);



	return 0;

}



static struct platform_driver rtc_device_driver = {

	.probe	= rtc_probe,

	.remove = rtc_remove,

	.driver = {

		.name	= "v3020",

		.owner	= THIS_MODULE,

	},

};



static __init int v3020_init(void)

{

	return platform_driver_register(&rtc_device_driver);

}



static __exit void v3020_exit(void)

{

	platform_driver_unregister(&rtc_device_driver);

}



module_init(v3020_init);

module_exit(v3020_exit);



MODULE_DESCRIPTION("V3020 RTC");

MODULE_AUTHOR("Raphael Assenat");

MODULE_LICENSE("GPL");

include/linux/rtc-v3020.h

0 → 100644
+35 −0
Original line number Diff line number Diff line 
/*

 * v3020.h - Registers definition and platform data structure for the v3020 RTC.

 *

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

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Copyright (C) 2006, 8D Technologies inc.

 */

#ifndef __LINUX_V3020_H

#define __LINUX_V3020_H



/* The v3020 has only one data pin but which one

 * is used depends on the board. */

struct v3020_platform_data {

	int leftshift; /* (1<<(leftshift)) & readl() */

};



#define V3020_STATUS_0	0x00

#define V3020_STATUS_1	0x01

#define V3020_SECONDS	0x02

#define V3020_MINUTES	0x03

#define V3020_HOURS		0x04

#define V3020_MONTH_DAY	0x05

#define V3020_MONTH		0x06

#define V3020_YEAR		0x07

#define V3020_WEEK_DAY	0x08

#define V3020_WEEK		0x09



#define V3020_IS_COMMAND(val) ((val)>=0x0E)



#define V3020_CMD_RAM2CLOCK	0x0E

#define V3020_CMD_CLOCK2RAM	0x0F



#endif /* __LINUX_V3020_H */

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