ds1302.c

标准linux 2.4.20 针对ds1302 的RTC 源码,具有充电功能!

/*!***************************************************************************
*!
*! 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 1.11  2001/06/14 12:35:52  jonashg
*! The ATA hack is back. It is unfortunately the only way to set g27 to output.
*!
*! Revision 1.9  2001/06/14 10:00:14  jonashg
*! No need for tempudelay to be inline anymore (had to adjust the usec to
*! loops conversion because of this to make it slow enough to be a udelay).
*!
*! Revision 1.8  2001/06/14 08:06:32  jonashg
*! Made tempudelay delay usecs (well, just a tad more).
*!
*! Revision 1.7  2001/06/13 14:18:11  jonashg
*! Only allow processes with SYS_TIME capability to set time and charge.
*!
*! Revision 1.6  2001/06/12 15:22:07  jonashg
*! * Made init function __init.
*! * Parameter to out_byte() is unsigned char.
*! * The magic number 42 has got a name.
*! * Removed comment about /proc (nothing is exported there).
*!
*! Revision 1.5  2001/06/12 14:35:13  jonashg
*! Gave the module a name and added it to printk's.
*!
*! Revision 1.4  2001/05/31 14:53:40  jonashg
*! Made tempudelay() inline so that the watchdog doesn't reset (see
*! function comment).
*!
*! 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 1.11 2001/06/14 12:35:52 jonashg Exp $
*!
*!***************************************************************************/
/*
#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/blkdev.h>
#include <asm/uaccess.h>
#include <asm/system.h>
//#include <asm/svinto.h>
#include <asm/io.h>*/
#include <linux/fs.h>
#include <linux/iobuf.h>
//#include <linux/major.h>   
#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/smp_lock.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/module.h>


//#include <asm/rtc.h>
//#include <linux/rtc.h>
#include "ds1302.h"

int    ds1302_open(struct inode*, struct file *);
int    ds1302_close(struct inode*, struct file *);
int    rtc_ioctl(struct inode*inode,struct file *flip,unsigned int cmd,unsigned long arg);


#define DS1302_RST  GPIO_F7
#define DS1302_SCL  GPIO_F4
#define DS1302_SDA  GPIO_F6

#define INN  0
#define OUTT 1


//#define RTC_MAJOR_NR 121 /* local major, change later */
static int RTC_MAJOR_NR=0;

static devfs_handle_t devfs_handle;
static const char ds1302_name[] = "ds1302";

/* 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)
#define TK_RST_OUT(x)   write_gpio_bit(GPIO_MODE_OUT | DS1302_RST,x)
#define TK_RST_DIR(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_SDA_OUT(x)   write_gpio_bit(GPIO_MODE_OUT | DS1302_SDA,x)
//#define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
#define TK_SCL_OUT(x)   write_gpio_bit(GPIO_MODE_OUT | DS1302_SCL,x)

//#define TK_SDA_IN()   ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
#define TK_SDA_IN()     read_gpio_bit(DS1302_SDA)

//#define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SDABIT, x)
//#define TK_SDA_DIR(x)   (if(x==1) set_gpio_ctrl(GPIO_MODE_OUT | DS1302_SDA); else set_gpio_ctrl(GPIO_MODE_IN | DS1302_SDA); )
#define TK_SDA_DIR(x) set_gpio_ctrl(x | DS1302_SDA)
//#define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SCLBIT, x)
#define TK_SCL_DIR(x)*/
/* 1 is out, 0 is in */

void TK_SDA_OUT(char x)
{
	write_gpio_bit(GPIO_MODE_OUT | DS1302_SDA,x);
}

char TK_SDA_IN(void)
{
	return(read_gpio_bit(DS1302_SDA));
}

void TK_SCL_OUT(char x)
{
	write_gpio_bit(GPIO_MODE_OUT | DS1302_SCL,x);
}
void TK_RST_OUT(char x)
{
	write_gpio_bit(GPIO_MODE_OUT | DS1302_RST,x);
}

void TK_SDA_DIR(char dir)
{
	if(dir==1)
		set_gpio_ctrl(GPIO_MODE_OUT | DS1302_SDA);
	else if(dir==0)
		 set_gpio_ctrl(GPIO_MODE_IN | DS1302_SDA);
	else;
}
void TK_SCL_DIR(char dir)
{
}
void TK_RST_DIR(char dir)
{
}

/*
 * 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 usecs) 
{
	volatile int loops;

	for(loops = usecs * 12; loops > 0; loops--)
		/* nothing */;	
}


/* Send 8 bits. */
static void
out_byte(unsigned char x) 
{
	int i;
	//TK_SDA_DIR(1);
	TK_SDA_DIR(OUTT);
	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);
	TK_SDA_DIR(INN);
}

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);
    TK_SDA_DIR(INN);
	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();
}

static void
ds1302_osc_enable(void)
{
	char tmp;
	start();
	out_byte(0x81);
	tmp=in_byte();
	stop();
	if((tmp&0x80)==0x00);
	else
	{
		start(); 
		out_byte(0x80);
		out_byte(0x00);
		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. */

#define MAGIC_PATTERN 0x42

static int
ds1302_probe(void) 
{
	int retval, res; 

	TK_RST_DIR(1);
	TK_SCL_DIR(1);
	//TK_SDA_DIR(0);
	TK_SDA_DIR(INN);
	ds1302_osc_enable();
	ds1302_writereg(RTC_TRICKLECHARGER, 0x00);//disable the trickle charger
	/* Try to talk to timekeeper. */