/*
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/*
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* linux/arch/arm/kernel/iic.c
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* linux/arch/arm/kernel/iic.c
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*
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*
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* Copyright (C) 1995, 1996 Russell King
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* Copyright (C) 1995, 1996 Russell King
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*
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*
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* IIC is used to get the current time from the CMOS rtc.
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* IIC is used to get the current time from the CMOS rtc.
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*/
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*/
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#include <asm/system.h>
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#include <asm/system.h>
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#include <asm/delay.h>
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#include <asm/delay.h>
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#include <asm/io.h>
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#include <asm/io.h>
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#include <asm/hardware.h>
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#include <asm/hardware.h>
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#define FORCE_ONES 0xdc
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#define FORCE_ONES 0xdc
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/*
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/*
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* if delay loop has been calibrated then us that,
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* if delay loop has been calibrated then us that,
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* else use IOC timer 1.
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* else use IOC timer 1.
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*/
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*/
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static void iic_delay (void)
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static void iic_delay (void)
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{
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{
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extern unsigned long loops_per_sec;
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extern unsigned long loops_per_sec;
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if (loops_per_sec != (1 << 12)) {
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if (loops_per_sec != (1 << 12)) {
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udelay(10);
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udelay(10);
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return;
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return;
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} else {
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} else {
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unsigned long flags;
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unsigned long flags;
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save_flags_cli(flags);
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save_flags_cli(flags);
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outb(254, IOC_T1LTCHL);
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outb(254, IOC_T1LTCHL);
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outb(255, IOC_T1LTCHH);
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outb(255, IOC_T1LTCHH);
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outb(0, IOC_T1GO);
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outb(0, IOC_T1GO);
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outb(1<<6, IOC_IRQCLRA); /* clear T1 irq */
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outb(1<<6, IOC_IRQCLRA); /* clear T1 irq */
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outb(4, IOC_T1LTCHL);
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outb(4, IOC_T1LTCHL);
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outb(0, IOC_T1LTCHH);
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outb(0, IOC_T1LTCHH);
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outb(0, IOC_T1GO);
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outb(0, IOC_T1GO);
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while ((inb(IOC_IRQSTATA) & (1<<6)) == 0);
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while ((inb(IOC_IRQSTATA) & (1<<6)) == 0);
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restore_flags(flags);
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restore_flags(flags);
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}
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}
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}
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}
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static inline void iic_start (void)
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static inline void iic_start (void)
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{
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{
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unsigned char out;
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unsigned char out;
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out = inb(IOC_CONTROL) | FORCE_ONES | 0x02;
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out = inb(IOC_CONTROL) | FORCE_ONES | 0x02;
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outb(out, IOC_CONTROL);
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outb(out, IOC_CONTROL);
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iic_delay();
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iic_delay();
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outb(out ^ 1, IOC_CONTROL);
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outb(out ^ 1, IOC_CONTROL);
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iic_delay();
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iic_delay();
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}
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}
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static inline void iic_stop (void)
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static inline void iic_stop (void)
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{
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{
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unsigned char out;
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unsigned char out;
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out = inb(IOC_CONTROL) | FORCE_ONES | 0x03;
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out = inb(IOC_CONTROL) | FORCE_ONES | 0x03;
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iic_delay();
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iic_delay();
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outb(out ^ 1, IOC_CONTROL);
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outb(out ^ 1, IOC_CONTROL);
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iic_delay();
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iic_delay();
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outb(out, IOC_CONTROL);
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outb(out, IOC_CONTROL);
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}
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}
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static int iic_sendbyte (unsigned char b)
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static int iic_sendbyte (unsigned char b)
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{
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{
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unsigned char out, in;
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unsigned char out, in;
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int i;
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int i;
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out = (inb(IOC_CONTROL) & 0xfc) | FORCE_ONES;
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out = (inb(IOC_CONTROL) & 0xfc) | FORCE_ONES;
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outb(out, IOC_CONTROL);
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outb(out, IOC_CONTROL);
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for (i = 7; i >= 0; i--) {
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for (i = 7; i >= 0; i--) {
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unsigned char c;
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unsigned char c;
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c = out | ((b & (1 << i)) ? 1 : 0);
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c = out | ((b & (1 << i)) ? 1 : 0);
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outb(c, IOC_CONTROL);
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outb(c, IOC_CONTROL);
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iic_delay();
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iic_delay();
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outb(c | 2, IOC_CONTROL);
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outb(c | 2, IOC_CONTROL);
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iic_delay();
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iic_delay();
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outb(c, IOC_CONTROL);
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outb(c, IOC_CONTROL);
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}
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}
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outb(out | 1, IOC_CONTROL);
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outb(out | 1, IOC_CONTROL);
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iic_delay();
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iic_delay();
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outb(out | 3, IOC_CONTROL);
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outb(out | 3, IOC_CONTROL);
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iic_delay();
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iic_delay();
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in = inb(IOC_CONTROL) & 1;
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in = inb(IOC_CONTROL) & 1;
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outb(out | 1, IOC_CONTROL);
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outb(out | 1, IOC_CONTROL);
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iic_delay();
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iic_delay();
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outb(out, IOC_CONTROL);
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outb(out, IOC_CONTROL);
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iic_delay();
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iic_delay();
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if(in) {
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if(in) {
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printk("No acknowledge from RTC\n");
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printk("No acknowledge from RTC\n");
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return 1;
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return 1;
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} else
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} else
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return 0;
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return 0;
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}
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}
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static unsigned char iic_recvbyte (void)
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static unsigned char iic_recvbyte (void)
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{
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{
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unsigned char out, in;
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unsigned char out, in;
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int i;
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int i;
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out = (inb(IOC_CONTROL) & 0xfc) | FORCE_ONES;
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out = (inb(IOC_CONTROL) & 0xfc) | FORCE_ONES;
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outb(out, IOC_CONTROL);
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outb(out, IOC_CONTROL);
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in = 0;
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in = 0;
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for (i = 7; i >= 0; i--) {
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for (i = 7; i >= 0; i--) {
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outb(out | 1, IOC_CONTROL);
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outb(out | 1, IOC_CONTROL);
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iic_delay();
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iic_delay();
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outb(out | 3, IOC_CONTROL);
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outb(out | 3, IOC_CONTROL);
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iic_delay();
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iic_delay();
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in = (in << 1) | (inb(IOC_CONTROL) & 1);
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in = (in << 1) | (inb(IOC_CONTROL) & 1);
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outb(out | 1, IOC_CONTROL);
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outb(out | 1, IOC_CONTROL);
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iic_delay();
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iic_delay();
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}
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}
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outb(out, IOC_CONTROL);
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outb(out, IOC_CONTROL);
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iic_delay();
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iic_delay();
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outb(out | 2, IOC_CONTROL);
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outb(out | 2, IOC_CONTROL);
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iic_delay();
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iic_delay();
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return in;
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return in;
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}
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}
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void iic_control (unsigned char addr, unsigned char loc, unsigned char *buf, int len)
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void iic_control (unsigned char addr, unsigned char loc, unsigned char *buf, int len)
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{
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{
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iic_start();
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iic_start();
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if (iic_sendbyte(addr & 0xfe))
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if (iic_sendbyte(addr & 0xfe))
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goto error;
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goto error;
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if (iic_sendbyte(loc))
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if (iic_sendbyte(loc))
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goto error;
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goto error;
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if (addr & 1) {
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if (addr & 1) {
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int i;
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int i;
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for (i = 0; i < len; i++)
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for (i = 0; i < len; i++)
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if (iic_sendbyte (buf[i]))
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if (iic_sendbyte (buf[i]))
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break;
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break;
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} else {
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} else {
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int i;
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int i;
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iic_stop();
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iic_stop();
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iic_start();
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iic_start();
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iic_sendbyte(addr|1);
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iic_sendbyte(addr|1);
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for (i = 0; i < len; i++)
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for (i = 0; i < len; i++)
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buf[i] = iic_recvbyte ();
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buf[i] = iic_recvbyte ();
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}
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}
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error:
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error:
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iic_stop();
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iic_stop();
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}
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}
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