358 lines
7.5 KiB
C
358 lines
7.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*!***************************************************************************
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*!
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*! FILE NAME : ds1302.c
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*!
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*! DESCRIPTION: Implements an interface for the DS1302 RTC
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*!
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*! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init, get_rtc_status
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*!
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*! ---------------------------------------------------------------------------
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*!
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*! (C) Copyright 1999, 2000, 2001 Axis Communications AB, LUND, SWEDEN
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*!
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*!***************************************************************************/
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/bcd.h>
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#include <linux/mutex.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <asm/rtc.h>
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#if defined(CONFIG_M32R)
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#include <asm/m32r.h>
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#endif
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#define RTC_MAJOR_NR 121 /* local major, change later */
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static DEFINE_MUTEX(rtc_mutex);
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static const char ds1302_name[] = "ds1302";
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/* Send 8 bits. */
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static void
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out_byte_rtc(unsigned int reg_addr, unsigned char x)
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{
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//RST H
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outw(0x0001,(unsigned long)PLD_RTCRSTODT);
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//write data
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outw(((x<<8)|(reg_addr&0xff)),(unsigned long)PLD_RTCWRDATA);
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//WE
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outw(0x0002,(unsigned long)PLD_RTCCR);
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//wait
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while(inw((unsigned long)PLD_RTCCR));
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//RST L
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outw(0x0000,(unsigned long)PLD_RTCRSTODT);
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}
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static unsigned char
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in_byte_rtc(unsigned int reg_addr)
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{
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unsigned char retval;
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//RST H
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outw(0x0001,(unsigned long)PLD_RTCRSTODT);
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//write data
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outw((reg_addr&0xff),(unsigned long)PLD_RTCRDDATA);
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//RE
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outw(0x0001,(unsigned long)PLD_RTCCR);
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//wait
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while(inw((unsigned long)PLD_RTCCR));
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//read data
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retval=(inw((unsigned long)PLD_RTCRDDATA) & 0xff00)>>8;
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//RST L
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outw(0x0000,(unsigned long)PLD_RTCRSTODT);
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return retval;
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}
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/* Enable writing. */
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static void
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ds1302_wenable(void)
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{
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out_byte_rtc(0x8e,0x00);
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}
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/* Disable writing. */
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static void
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ds1302_wdisable(void)
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{
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out_byte_rtc(0x8e,0x80);
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}
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/* Read a byte from the selected register in the DS1302. */
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unsigned char
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ds1302_readreg(int reg)
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{
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unsigned char x;
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x=in_byte_rtc((0x81 | (reg << 1))); /* read register */
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return x;
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}
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/* Write a byte to the selected register. */
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void
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ds1302_writereg(int reg, unsigned char val)
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{
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ds1302_wenable();
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out_byte_rtc((0x80 | (reg << 1)),val);
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ds1302_wdisable();
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}
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void
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get_rtc_time(struct rtc_time *rtc_tm)
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{
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unsigned long flags;
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local_irq_save(flags);
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rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
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rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
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rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
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rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
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rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
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rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
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local_irq_restore(flags);
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rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
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rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
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rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
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rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
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rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
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rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
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/*
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* Account for differences between how the RTC uses the values
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* and how they are defined in a struct rtc_time;
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*/
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if (rtc_tm->tm_year <= 69)
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rtc_tm->tm_year += 100;
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rtc_tm->tm_mon--;
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}
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static unsigned char days_in_mo[] =
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{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
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static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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unsigned long flags;
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switch(cmd) {
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case RTC_RD_TIME: /* read the time/date from RTC */
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{
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struct rtc_time rtc_tm;
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memset(&rtc_tm, 0, sizeof (struct rtc_time));
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mutex_lock(&rtc_mutex);
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get_rtc_time(&rtc_tm);
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mutex_unlock(&rtc_mutex);
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if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
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return -EFAULT;
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return 0;
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}
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case RTC_SET_TIME: /* set the RTC */
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{
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struct rtc_time rtc_tm;
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unsigned char mon, day, hrs, min, sec, leap_yr;
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unsigned int yrs;
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if (!capable(CAP_SYS_TIME))
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return -EPERM;
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if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
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return -EFAULT;
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yrs = rtc_tm.tm_year + 1900;
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mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
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day = rtc_tm.tm_mday;
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hrs = rtc_tm.tm_hour;
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min = rtc_tm.tm_min;
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sec = rtc_tm.tm_sec;
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if ((yrs < 1970) || (yrs > 2069))
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return -EINVAL;
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leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
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if ((mon > 12) || (day == 0))
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return -EINVAL;
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if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
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return -EINVAL;
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if ((hrs >= 24) || (min >= 60) || (sec >= 60))
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return -EINVAL;
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if (yrs >= 2000)
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yrs -= 2000; /* RTC (0, 1, ... 69) */
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else
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yrs -= 1900; /* RTC (70, 71, ... 99) */
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sec = bin2bcd(sec);
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min = bin2bcd(min);
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hrs = bin2bcd(hrs);
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day = bin2bcd(day);
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mon = bin2bcd(mon);
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yrs = bin2bcd(yrs);
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mutex_lock(&rtc_mutex);
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local_irq_save(flags);
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CMOS_WRITE(yrs, RTC_YEAR);
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CMOS_WRITE(mon, RTC_MONTH);
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CMOS_WRITE(day, RTC_DAY_OF_MONTH);
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CMOS_WRITE(hrs, RTC_HOURS);
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CMOS_WRITE(min, RTC_MINUTES);
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CMOS_WRITE(sec, RTC_SECONDS);
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local_irq_restore(flags);
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mutex_unlock(&rtc_mutex);
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/* Notice that at this point, the RTC is updated but
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* the kernel is still running with the old time.
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* You need to set that separately with settimeofday
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* or adjtimex.
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*/
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return 0;
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}
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case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
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{
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int tcs_val;
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if (!capable(CAP_SYS_TIME))
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return -EPERM;
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if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
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return -EFAULT;
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mutex_lock(&rtc_mutex);
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tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
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ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
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mutex_unlock(&rtc_mutex);
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return 0;
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}
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default:
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return -EINVAL;
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}
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}
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int
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get_rtc_status(char *buf)
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{
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char *p;
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struct rtc_time tm;
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p = buf;
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get_rtc_time(&tm);
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/*
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* There is no way to tell if the luser has the RTC set for local
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* time or for Universal Standard Time (GMT). Probably local though.
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*/
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p += sprintf(p,
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"rtc_time\t: %02d:%02d:%02d\n"
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"rtc_date\t: %04d-%02d-%02d\n",
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tm.tm_hour, tm.tm_min, tm.tm_sec,
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tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
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return p - buf;
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}
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/* The various file operations we support. */
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static const struct file_operations rtc_fops = {
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.owner = THIS_MODULE,
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.unlocked_ioctl = rtc_ioctl,
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.llseek = noop_llseek,
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};
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/* Probe for the chip by writing something to its RAM and try reading it back. */
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#define MAGIC_PATTERN 0x42
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static int __init
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ds1302_probe(void)
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{
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int retval, res, baur;
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baur=(boot_cpu_data.bus_clock/(2*1000*1000));
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printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur);
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outw(0x0000,(unsigned long)PLD_RTCCR);
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outw(0x0000,(unsigned long)PLD_RTCRSTODT);
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outw(baur,(unsigned long)PLD_RTCBAUR);
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/* Try to talk to timekeeper. */
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ds1302_wenable();
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/* write RAM byte 0 */
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/* write something magic */
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out_byte_rtc(0xc0,MAGIC_PATTERN);
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/* read RAM byte 0 */
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if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) {
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char buf[100];
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ds1302_wdisable();
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printk("%s: RTC found.\n", ds1302_name);
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get_rtc_status(buf);
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printk(buf);
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retval = 1;
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} else {
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printk("%s: RTC not found.\n", ds1302_name);
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retval = 0;
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}
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return retval;
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}
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/* Just probe for the RTC and register the device to handle the ioctl needed. */
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int __init
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ds1302_init(void)
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{
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if (!ds1302_probe()) {
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return -1;
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}
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return 0;
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}
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static int __init ds1302_register(void)
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{
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ds1302_init();
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if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
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printk(KERN_INFO "%s: unable to get major %d for rtc\n",
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ds1302_name, RTC_MAJOR_NR);
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return -1;
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}
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return 0;
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}
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module_init(ds1302_register);
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