/*!*************************************************************************** *! *! 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);