--- /dev/null
+/*!***************************************************************************
+*!
+*! 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);
projects / linux / commitdiff