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linux/drivers/rtc/rtc-ds1742.c
Torsten Ertbjerg Rasmussen f9231a0ca1 [PATCH] rtc: ds1743 support 
The real time clocks ds1742 and ds1743 differs only in the size of the
nvram.  This patch changes the existing ds1742 driver to support also
ds1743.  The main change is that the nvram size is determined from the
resource attached to the device.

The patch have benefitted from suggestions from Atsushi Nemeto, who is the
author of the ds1742 driver.

Signed-off-by: Torsten Rasmussen Rasmussen <tr@newtec.dk>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:43 -08:00

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/*
* 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.
*
* Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk>
* - nvram size determined from resource
* - this ds1742 driver now supports ds1743.
*/
#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 "0.3"
#define RTC_SIZE 8
#define RTC_CONTROL 0
#define RTC_CENTURY 0
#define RTC_SECONDS 1
#define RTC_MINUTES 2
#define RTC_HOURS 3
#define RTC_DAY 4
#define RTC_DATE 5
#define RTC_MONTH 6
#define RTC_YEAR 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_nvram;
void __iomem *ioaddr_rtc;
size_t size_nvram;
size_t size;
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_rtc;
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_rtc;
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 const 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_nvram;
ssize_t count;
for (count = 0; size > 0 && pos < pdata->size_nvram; 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_nvram;
ssize_t count;
for (count = 0; size > 0 && pos < pdata->size_nvram; 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,
},
.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;
pdata->size = res->end - res->start + 1;
if (!request_mem_region(res->start, pdata->size, pdev->name)) {
ret = -EBUSY;
goto out;
}
pdata->baseaddr = res->start;
ioaddr = ioremap(pdata->baseaddr, pdata->size);
if (!ioaddr) {
ret = -ENOMEM;
goto out;
}
pdata->ioaddr_nvram = ioaddr;
pdata->size_nvram = pdata->size - RTC_SIZE;
pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
/* turn RTC on if it was not on */
ioaddr = pdata->ioaddr_rtc;
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);
ds1742_nvram_attr.size = max(ds1742_nvram_attr.size,
pdata->size_nvram);
ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);
if (ret)
goto out;
return 0;
out:
if (pdata->rtc)
rtc_device_unregister(pdata->rtc);
if (pdata->ioaddr_nvram)
iounmap(pdata->ioaddr_nvram);
if (pdata->baseaddr)
release_mem_region(pdata->baseaddr, pdata->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_nvram);
release_mem_region(pdata->baseaddr, pdata->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);
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