[PATCH] m32r: ds1302 driver

This is a DS1302 real-time clock driver.

It is moved from arch/m32r/drivers/, has been originally taken from
arch/cris/arch-v10/drivers/ds1302.c.

Currently, this driver supports only m32r target boards.  Maybe some work will
be required to support other target.
Signed-off-by: Hayato Fujiwara <fujiwara@linux-m32r.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/char/Kconfig

@@ -780,6 +780,15 @@ config EFI_RTC
 	bool "EFI Real Time Clock Services"
 	depends on IA64
 
+config DS1302
+	tristate "DS1302 RTC support"
+	depends on M32R && (PLAT_M32700UT || PLAT_OPSPUT)
+	help
+	  If you say Y here and create a character special file /dev/rtc with
+	  major number 121 and minor number 0 using mknod ("man mknod"), you
+	  will get access to the real time clock (or hardware clock) built
+	  into your computer.
+
 config COBALT_LCD
 	bool "Support for Cobalt LCD"
 	depends on MIPS_COBALT

drivers/char/Makefile

@@ -63,6 +63,7 @@ obj-$(CONFIG_GEN_RTC) += genrtc.o
 obj-$(CONFIG_EFI_RTC) += efirtc.o
 obj-$(CONFIG_SGI_DS1286) += ds1286.o
 obj-$(CONFIG_SGI_IP27_RTC) += ip27-rtc.o
+obj-$(CONFIG_DS1302) += ds1302.o
 ifeq ($(CONFIG_GENERIC_NVRAM),y)
   obj-$(CONFIG_NVRAM) += generic_nvram.o
 else

drivers/char/ds1302.c

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

include/asm-m32r/rtc.h

@@ -29,7 +29,7 @@
 #  define RTC_TCR_4KOHM 	0x02	/* xxxxxx10 4kOhm */
 #  define RTC_TCR_8KOHM 	0x03	/* xxxxxx11 8kOhm */
 
-#ifdef CONFIG_M32700UT_DS1302
+#ifdef CONFIG_DS1302
 extern unsigned char ds1302_readreg(int reg);
 extern void ds1302_writereg(int reg, unsigned char val);
 extern int ds1302_init(void);