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[PATCH] Add v3020 RTC support
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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: Raphael Assenat <raph@raphnet.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Raphael Assenat authored and Linus Torvalds committed Jun 25, 2006
1 parent 9be05b5 commit 362600f
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10 changes: 10 additions & 0 deletions drivers/rtc/Kconfig
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Expand Up @@ -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
1 change: 1 addition & 0 deletions drivers/rtc/Makefile
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Expand Up @@ -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
264 changes: 264 additions & 0 deletions drivers/rtc/rtc-v3020.c
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@@ -0,0 +1,264 @@
/* 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");
35 changes: 35 additions & 0 deletions include/linux/rtc-v3020.h
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@@ -0,0 +1,35 @@
/*
* 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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