diff options
Diffstat (limited to 'drivers/char/ds1302.c')
| -rw-r--r-- | drivers/char/ds1302.c | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/drivers/char/ds1302.c b/drivers/char/ds1302.c new file mode 100644 index 0000000..a75e860 --- /dev/null +++ b/drivers/char/ds1302.c @@ -0,0 +1,354 @@ +/*!*************************************************************************** +*! +*! 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/config.h> + +#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); + local_irq_disable(); + + 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); + local_irq_disable(); + 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 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); |