/*!***************************************************************************
*!
*! FILE NAME : ds1302.c
*!
*! DESCRIPTION: Implements an interface for the DS1302 RTC
*!
*! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init, get_rtc_status
*!
*! ---------------------------------------------------------------------------
*!
*! (C) Copyright 1999, 2000, 2001 Axis Communications AB, LUND, SWEDEN
*!
*!***************************************************************************/
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/bcd.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/rtc.h>
#if defined(CONFIG_M32R)
#include <asm/m32r.h>
#endif
#define RTC_MAJOR_NR 121 /* local major, change later */
static const char ds1302_name[] = "ds1302";
/* Send 8 bits. */
static void
out_byte_rtc(unsigned int reg_addr, unsigned char x)
{
//RST H
outw(0x0001,(unsigned long)PLD_RTCRSTODT);
//write data
outw(((x<<8)|(reg_addr&0xff)),(unsigned long)PLD_RTCWRDATA);
//WE
outw(0x0002,(unsigned long)PLD_RTCCR);
//wait
while(inw((unsigned long)PLD_RTCCR));
//RST L
outw(0x0000,(unsigned long)PLD_RTCRSTODT);
}
static unsigned char
in_byte_rtc(unsigned int reg_addr)
{
unsigned char retval;
//RST H
outw(0x0001,(unsigned long)PLD_RTCRSTODT);
//write data
outw((reg_addr&0xff),(unsigned long)PLD_RTCRDDATA);
//RE
outw(0x0001,(unsigned long)PLD_RTCCR);
//wait
while(inw((unsigned long)PLD_RTCCR));
//read data
retval=(inw((unsigned long)PLD_RTCRDDATA) & 0xff00)>>8;
//RST L
outw(0x0000,(unsigned long)PLD_RTCRSTODT);
return retval;
}
/* Enable writing. */
static void
ds1302_wenable(void)
{
out_byte_rtc(0x8e,0x00);
}
/* Disable writing. */
static void
ds1302_wdisable(void)
{
out_byte_rtc(0x8e,0x80);
}
/* Read a byte from the selected register in the DS1302. */
unsigned char
ds1302_readreg(int reg)
{
unsigned char x;
x=in_byte_rtc((0x81 | (reg << 1))); /* read register */
return x;
}
/* Write a byte to the selected register. */
void
ds1302_writereg(int reg, unsigned char val)
{
ds1302_wenable();
out_byte_rtc((0x80 | (reg << 1)),val);
ds1302_wdisable();
}
void
get_rtc_time(struct rtc_time *rtc_tm)
{
unsigned long flags;
local_irq_save(flags);
rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
local_irq_restore(flags);
BCD_TO_BIN(rtc_tm->tm_sec);
BCD_TO_BIN(rtc_tm->tm_min);
BCD_TO_BIN(rtc_tm->tm_hour);
BCD_TO_BIN(rtc_tm->tm_mday);
BCD_TO_BIN(rtc_tm->tm_mon);
BCD_TO_BIN(rtc_tm->tm_year);
/*
* Account for differences between how the RTC uses the values
* and how they are defined in a struct rtc_time;
*/
if (rtc_tm->tm_year <= 69)
rtc_tm->tm_year += 100;
rtc_tm->tm_mon--;
}
static unsigned char days_in_mo[] =
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
static int
rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
unsigned long flags;
switch(cmd) {
case RTC_RD_TIME: /* read the time/date from RTC */
{
struct rtc_time rtc_tm;
memset(&rtc_tm, 0, sizeof (struct rtc_time));
get_rtc_time(&rtc_tm);
if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
return -EFAULT;
return 0;
}
case RTC_SET_TIME: /* set the RTC */
{
struct rtc_time rtc_tm;
unsigned char mon, day, hrs, min, sec, leap_yr;
unsigned int yrs;
if (!capable(CAP_SYS_TIME))
return -EPERM;
if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
return -EFAULT;
yrs = rtc_tm.tm_year + 1900;
mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
day = rtc_tm.tm_mday;
hrs = rtc_tm.tm_hour;
min = rtc_tm.tm_min;
sec = rtc_tm.tm_sec;
if ((yrs < 1970) || (yrs > 2069))
return -EINVAL;
leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
if ((mon > 12) || (day == 0))
return -EINVAL;
if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
return -EINVAL;
if ((hrs >= 24) || (min >= 60) || (sec >= 60))
return -EINVAL;
if (yrs >= 2000)
yrs -= 2000; /* RTC (0, 1, ... 69) */
else
yrs -= 1900; /* RTC (70, 71, ... 99) */
BIN_TO_BCD(sec);
BIN_TO_BCD(min);
BIN_TO_BCD(hrs);
BIN_TO_BCD(day);
BIN_TO_BCD(mon);
BIN_TO_BCD(yrs);
local_irq_save(flags);
CMOS_WRITE(yrs, RTC_YEAR);
CMOS_WRITE(mon, RTC_MONTH);
CMOS_WRITE(day, RTC_DAY_OF_MONTH);
CMOS_WRITE(hrs, RTC_HOURS);
CMOS_WRITE(min, RTC_MINUTES);
CMOS_WRITE(sec, RTC_SECONDS);
local_irq_restore(flags);
/* Notice that at this point, the RTC is updated but
* the kernel is still running with the old time.
* You need to set that separately with settimeofday
* or adjtimex.
*/
return 0;
}
case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
{
int tcs_val;
if (!capable(CAP_SYS_TIME))
return -EPERM;
if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
return -EFAULT;
tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
return 0;
}
default:
return -EINVAL;
}
}
int
get_rtc_status(char *buf)
{
char *p;
struct rtc_time tm;
p = buf;
get_rtc_time(&tm);
/*
* There is no way to tell if the luser has the RTC set for local
* time or for Universal Standard Time (GMT). Probably local though.
*/
p += sprintf(p,
"rtc_time\t: %02d:%02d:%02d\n"
"rtc_date\t: %04d-%02d-%02d\n",
tm.tm_hour, tm.tm_min, tm.tm_sec,
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
return p - buf;
}
/* The various file operations we support. */
static const struct file_operations rtc_fops = {
.owner = THIS_MODULE,
.ioctl = rtc_ioctl,
};
/* Probe for the chip by writing something to its RAM and try reading it back. */
#define MAGIC_PATTERN 0x42
static int __init
ds1302_probe(void)
{
int retval, res, baur;
baur=(boot_cpu_data.bus_clock/(2*1000*1000));
printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur);
outw(0x0000,(unsigned long)PLD_RTCCR);
outw(0x0000,(unsigned long)PLD_RTCRSTODT);
outw(baur,(unsigned long)PLD_RTCBAUR);
/* Try to talk to timekeeper. */
ds1302_wenable();
/* write RAM byte 0 */
/* write something magic */
out_byte_rtc(0xc0,MAGIC_PATTERN);
/* read RAM byte 0 */
if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) {
char buf[100];
ds1302_wdisable();
printk("%s: RTC found.\n", ds1302_name);
get_rtc_status(buf);
printk(buf);
retval = 1;
} else {
printk("%s: RTC not found.\n", ds1302_name);
retval = 0;
}
return retval;
}
/* Just probe for the RTC and register the device to handle the ioctl needed. */
int __init
ds1302_init(void)
{
if (!ds1302_probe()) {
return -1;
}
return 0;
}
static int __init ds1302_register(void)
{
ds1302_init();
if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
printk(KERN_INFO "%s: unable to get major %d for rtc\n",
ds1302_name, RTC_MAJOR_NR);
return -1;
}
return 0;
}
module_init(ds1302_register);
