patch-2.4.5 linux/arch/cris/drivers/ds1302.c

• Lines: 489
• Date: Tue May 1 16:04:56 2001
• Orig file: v2.4.4/linux/arch/cris/drivers/ds1302.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.4/linux/arch/cris/drivers/ds1302.c linux/arch/cris/drivers/ds1302.c
@@ -0,0 +1,488 @@
+/*!***************************************************************************
+*!
+*! FILE NAME  : ds1302.c
+*!
+*! DESCRIPTION: Implements an interface for the DS1302 RTC through Etrax I/O
+*!
+*! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init, get_rtc_status
+*!
+*! $Log: ds1302.c,v $
+*! Revision 1.3  2001/03/26 16:03:06  bjornw
+*! Needs linux/config.h
+*!
+*! Revision 1.2  2001/03/20 19:42:00  bjornw
+*! Use the ETRAX prefix on the DS1302 options
+*!
+*! Revision 1.1  2001/03/20 09:13:50  magnusmn
+*! Linux 2.4 port
+*!
+*! Revision 1.10  2000/07/05 15:38:23  bjornw
+*! Dont update kernel time when a RTC_SET_TIME is done
+*!
+*! Revision 1.9  2000/03/02 15:42:59  macce
+*! * Hack to make RTC work on all 2100/2400
+*!
+*! Revision 1.8  2000/02/23 16:59:18  torbjore
+*! added setup of R_GEN_CONFIG when RTC is connected to the generic port.
+*!
+*! Revision 1.7  2000/01/17 15:51:43  johana
+*! Added RTC_SET_CHARGE ioctl to enable trickle charger.
+*!
+*! Revision 1.6  1999/10/27 13:19:47  bjornw
+*! Added update_xtime_from_cmos which reads back the updated RTC into the kernel.
+*! /dev/rtc calls it now.
+*!
+*! Revision 1.5  1999/10/27 12:39:37  bjornw
+*! Disabled superuser check. Anyone can now set the time.
+*!
+*! Revision 1.4  1999/09/02 13:27:46  pkj
+*! Added shadow for R_PORT_PB_CONFIG.
+*! Renamed port_g_shadow to port_g_data_shadow.
+*!
+*! Revision 1.3  1999/09/02 08:28:06  pkj
+*! Made it possible to select either port PB or the generic port for the RST
+*! signal line to the DS1302 RTC.
+*! Also make sure the RST bit is configured as output on Port PB (if used).
+*!
+*! Revision 1.2  1999/09/01 14:47:20  bjornw
+*! Added support for /dev/rtc operations with ioctl RD_TIME and SET_TIME to read
+*! and set the date. Register as major 121.
+*!
+*! Revision 1.1  1999/09/01 09:45:29  bjornw
+*! Implemented a DS1302 RTC driver.
+*!
+*!
+*! ---------------------------------------------------------------------------
+*!
+*! (C) Copyright 1999, 2000, 2001  Axis Communications AB, LUND, SWEDEN
+*!
+*! $Id: ds1302.c,v 1.3 2001/03/26 16:03:06 bjornw Exp $
+*!
+*!***************************************************************************/
+
+#include <linux/config.h>
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/delay.h>
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/svinto.h>
+#include <asm/io.h>
+#include <asm/rtc.h>
+
+#define RTC_MAJOR_NR 121 /* local major, change later */
+
+/* The DS1302 might be connected to different bits on different products. 
+ * It has three signals - SDA, SCL and RST. RST and SCL are always outputs,
+ * but SDA can have a selected direction.
+ * For now, only PORT_PB is hardcoded.
+ */
+
+/* The RST bit may be on either the Generic Port or Port PB */
+#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
+#define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA,  port_g_data_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
+#define TK_RST_DIR(x)
+#else
+#define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
+#define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
+#endif
+
+
+#define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
+#define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
+
+#define TK_SDA_IN()   ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
+/* 1 is out, 0 is in */
+#define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SDABIT, x)
+#define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SCLBIT, x)
+
+
+/*
+ * The reason for tempudelay and not udelay is that loops_per_usec
+ * (used in udelay) is not set when functions here are called from time.c 
+ */
+
+static void tempudelay(int time) 
+{
+	int i;
+	for(i = 0; i < time * 10000; i++);	
+}
+
+
+/* send 8 bits */
+static void
+out_byte(int x) 
+{
+	int i;
+	TK_SDA_DIR(1);
+	for (i = 8; i--;) {
+		/* the chip latches incoming bits on the rising edge of SCL */
+		TK_SCL_OUT(0);
+		TK_SDA_OUT(x & 1);
+		tempudelay(1);
+		TK_SCL_OUT(1);
+		tempudelay(1);
+		x >>= 1;
+	}
+	TK_SDA_DIR(0);
+}
+
+static unsigned char
+in_byte(void) 
+{
+	unsigned char x = 0;
+	int i;
+
+	/* Read byte. Bits come LSB first, on the falling edge of SCL.
+	 * Assume SDA is in input direction already
+	 */
+	TK_SDA_DIR(0);
+
+	for (i = 8; i--;) {
+		TK_SCL_OUT(0);
+		tempudelay(1);
+		x >>= 1;
+		x |= (TK_SDA_IN() << 7);
+		TK_SCL_OUT(1);
+		tempudelay(1);
+	}
+
+	return x;
+}
+
+/* prepares for a transaction by de-activating RST (active-low) */
+
+static void
+start(void) 
+{
+	TK_SCL_OUT(0);
+	tempudelay(1);
+	TK_RST_OUT(0);
+	tempudelay(5);
+	TK_RST_OUT(1);	
+}
+
+/* ends a transaction by taking RST active again */
+
+static void
+stop(void) 
+{
+	tempudelay(2);
+	TK_RST_OUT(0);
+}
+
+/* enable writing */
+
+static void
+ds1302_wenable(void) 
+{
+	start(); 	
+	out_byte(0x8e); /* Write control register  */
+	out_byte(0x00); /* Disable write protect bit 7 = 0 */
+	stop();
+}
+
+/* disable writing */
+
+static void
+ds1302_wdisable(void) 
+{
+	start();
+	out_byte(0x8e); /* Write control register  */
+	out_byte(0x80); /* Disable write protect bit 7 = 0 */
+	stop();
+}
+
+/* probe for the chip by writing something to its RAM and try reading it back */
+
+static int
+ds1302_probe(void) 
+{
+	int retval, res; 
+
+	TK_RST_DIR(1);
+	TK_SCL_DIR(1);
+	TK_SDA_DIR(0);
+	
+	/* try to talk to timekeeper */
+
+	ds1302_wenable();  
+	start();
+	out_byte(0xc0); /* write RAM byte 0 */	
+	out_byte(0x42); /* write something magic */
+	start();
+	out_byte(0xc1); /* read RAM byte 0 */
+
+	if((res = in_byte()) == 0x42) {
+		char buf[100];
+		stop();
+		ds1302_wdisable();
+		printk("DS1302 RTC found.\n");
+                printk("SDA, SCL, RST on PB%i, PB%i, %s%i\n",
+                       CONFIG_ETRAX_DS1302_SDABIT,
+                       CONFIG_ETRAX_DS1302_SCLBIT,
+#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
+                       "GENIO",
+#else
+                       "PB",
+#endif
+                       CONFIG_ETRAX_DS1302_RSTBIT
+                       );
+                get_rtc_status(buf);
+                printk(buf);
+		retval = 1;
+	} else {
+		stop();
+		printk("DS1302 RTC not found.\n");
+		retval = 0;
+	}
+
+	return retval;
+}
+
+
+/* read a byte from the selected register in the DS1302 */
+
+unsigned char
+ds1302_readreg(int reg) 
+{
+	unsigned char x;
+
+	start();
+	out_byte(0x81 | (reg << 1)); /* Read register */
+	x = in_byte();
+	stop();
+
+	return x;
+}
+
+/* write a byte to the selected register */
+
+void
+ds1302_writereg(int reg, unsigned char val) 
+{
+	ds1302_wenable();
+	start();
+	out_byte(0x80 | (reg << 1)); /* Write register */
+	out_byte(val);
+	stop();
+	ds1302_wdisable();
+}
+
+void
+get_rtc_time(struct rtc_time *rtc_tm) 
+{
+	unsigned long flags;
+
+	save_flags(flags);
+	cli();
+
+	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);
+
+	restore_flags(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;
+						
+			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 char save_control, save_freq_select;
+			unsigned int yrs;
+#if 0
+			if (!suser())
+				return -EACCES;
+#endif			
+			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);
+
+			save_flags(flags);
+			cli();
+			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);
+			restore_flags(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;                        
+			unsigned char save_control, save_freq_select;
+#if 0
+			if (!suser())
+				return -EACCES;
+#endif
+			
+			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 -ENOIOCTLCMD;
+	}
+}
+
+/*
+ *	Info exported via "/proc/rtc".
+ */
+
+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,	
+}; 
+
+/* just probe for the RTC and register the device to handle the ioctl needed */
+
+int
+ds1302_init(void) 
+{ 
+  
+ /* Ugly hack to handle both 2100 and 2400 hardware.
+    Remove...
+ */
+	if(!ds1302_probe()) {
+#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
+    	/*
+     	* Make sure that R_GEN_CONFIG is 
+     	* setup correct.
+     	*/
+    		genconfig_shadow = ( (genconfig_shadow & ~IO_MASK(R_GEN_CONFIG, ata) ) | 
+                           ( IO_STATE( R_GEN_CONFIG, ata, select ) ) );    
+    		*R_GEN_CONFIG = genconfig_shadow;
+    		if(!ds1302_probe())
+      			return -1;
+#else
+    		return -1;
+#endif
+  	}
+  
+	if (register_chrdev(RTC_MAJOR_NR, "rtc", &rtc_fops)) {
+		printk("unable to get major %d for rtc\n", RTC_MAJOR_NR);
+		return -1;
+	}
+	return 0;
+}
+
+