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/*
* 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 <mach/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",
__func__,
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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