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/*
* Basic I2C functions
*
* Copyright (c) 2004 Texas Instruments
*
* This package is free software; you can redistribute it and/or
* modify it under the terms of the license found in the file
* named COPYING that should have accompanied this file.
*
* THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Author: Jian Zhang jzhang@ti.com, Texas Instruments
*
* Copyright (c) 2003 Wolfgang Denk, wd@denx.de
* Rewritten to fit into the current U-Boot framework
*
* Adapted for OMAP2420 I2C, r-woodruff2@ti.com
*
*/
#include <common.h>
#include <asm/arch/i2c.h>
#include <asm/io.h>
#define inw(a) __raw_readw(a)
#define outw(a,v) __raw_writew(a,v)
#ifdef CONFIG_DRIVER_OMAP24XX_I2C
static void wait_for_bb (void);
static u16 wait_for_pin (void);
void flush_fifo(void);
void i2c_init (int speed, int slaveadd)
{
u16 scl;
if (inw (I2C_CON) & I2C_CON_EN) {
outw (0, I2C_CON);
udelay (50000);
}
/* 12Mhz I2C module clock */
outw (0, I2C_PSC);
speed = speed/1000; /* 100 or 400 */
scl = ((12000/(speed*2)) - 7); /* use 7 when PSC = 0 */
outw (scl, I2C_SCLL);
outw (scl, I2C_SCLH);
/* own address */
outw (slaveadd, I2C_OA);
outw (I2C_CON_EN, I2C_CON);
outw (0, I2C_CNT);
/* have to enable intrrupts or OMAP i2c module doesn't work */
outw (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
I2C_IE_NACK_IE | I2C_IE_AL_IE, I2C_IE);
udelay (1000);
}
static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
{
int i2c_error = 0;
u16 status;
/* wait until bus not busy */
wait_for_bb ();
/* one byte only */
outw (1, I2C_CNT);
/* set slave address */
outw (devaddr, I2C_SA);
/* no stop bit needed here */
outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, I2C_CON);
status = wait_for_pin ();
if (status & I2C_STAT_XRDY) {
/* Important: have to use byte access */
*(volatile u8 *) (I2C_DATA) = regoffset;
udelay (20000);
if (inw (I2C_STAT) & I2C_STAT_NACK) {
i2c_error = 1;
}
} else {
i2c_error = 1;
}
if (!i2c_error) {
/* free bus, otherwise we can't use a combined transction */
outw (0, I2C_CON);
while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) {
udelay (10000);
/* Have to clear pending interrupt to clear I2C_STAT */
outw (0xFFFF, I2C_STAT);
}
wait_for_bb ();
/* set slave address */
outw (devaddr, I2C_SA);
/* read one byte from slave */
outw (1, I2C_CNT);
/* need stop bit here */
outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP,
I2C_CON);
status = wait_for_pin ();
if (status & I2C_STAT_RRDY) {
*value = inw (I2C_DATA);
udelay (20000);
} else {
i2c_error = 1;
}
if (!i2c_error) {
outw (I2C_CON_EN, I2C_CON);
while (inw (I2C_STAT)
|| (inw (I2C_CON) & I2C_CON_MST)) {
udelay (10000);
outw (0xFFFF, I2C_STAT);
}
}
}
flush_fifo();
outw (0xFFFF, I2C_STAT);
outw (0, I2C_CNT);
return i2c_error;
}
static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
{
int i2c_error = 0;
u16 status, stat;
/* wait until bus not busy */
wait_for_bb ();
/* two bytes */
outw (2, I2C_CNT);
/* set slave address */
outw (devaddr, I2C_SA);
/* stop bit needed here */
outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
I2C_CON_STP, I2C_CON);
/* wait until state change */
status = wait_for_pin ();
if (status & I2C_STAT_XRDY) {
/* send out two bytes */
outw ((value << 8) + regoffset, I2C_DATA);
/* must have enough delay to allow BB bit to go low */
udelay (50000);
if (inw (I2C_STAT) & I2C_STAT_NACK) {
i2c_error = 1;
}
} else {
i2c_error = 1;
}
if (!i2c_error) {
outw (I2C_CON_EN, I2C_CON);
while ((stat = inw (I2C_STAT)) || (inw (I2C_CON) & I2C_CON_MST)) {
udelay (1000);
/* have to read to clear intrrupt */
outw (0xFFFF, I2C_STAT);
}
}
flush_fifo();
outw (0xFFFF, I2C_STAT);
outw (0, I2C_CNT);
return i2c_error;
}
void flush_fifo(void)
{ u16 stat;
/* note: if you try and read data when its not there or ready
* you get a bus error
*/
while(1){
stat = inw(I2C_STAT);
if(stat == I2C_STAT_RRDY){
inw(I2C_DATA);
outw(I2C_STAT_RRDY,I2C_STAT);
udelay(1000);
}else
break;
}
}
int i2c_probe (uchar chip)
{
int res = 1; /* default = fail */
if (chip == inw (I2C_OA)) {
return res;
}
/* wait until bus not busy */
wait_for_bb ();
/* try to read one byte */
outw (1, I2C_CNT);
/* set slave address */
outw (chip, I2C_SA);
/* stop bit needed here */
outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, I2C_CON);
/* enough delay for the NACK bit set */
udelay (50000);
if (!(inw (I2C_STAT) & I2C_STAT_NACK)) {
res = 0; /* success case */
flush_fifo();
outw(0xFFFF, I2C_STAT);
} else {
outw(0xFFFF, I2C_STAT); /* failue, clear sources*/
outw (inw (I2C_CON) | I2C_CON_STP, I2C_CON); /* finish up xfer */
udelay(20000);
wait_for_bb ();
}
flush_fifo();
outw (0, I2C_CNT); /* don't allow any more data in...we don't want it.*/
outw(0xFFFF, I2C_STAT);
return res;
}
int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
{
int i;
if (alen > 1) {
printf ("I2C read: addr len %d not supported\n", alen);
return 1;
}
if (addr + len > 256) {
printf ("I2C read: address out of range\n");
return 1;
}
for (i = 0; i < len; i++) {
if (i2c_read_byte (chip, addr + i, &buffer[i])) {
printf ("I2C read: I/O error\n");
i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);
return 1;
}
}
return 0;
}
int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
{
int i;
if (alen > 1) {
printf ("I2C read: addr len %d not supported\n", alen);
return 1;
}
if (addr + len > 256) {
printf ("I2C read: address out of range\n");
return 1;
}
for (i = 0; i < len; i++) {
if (i2c_write_byte (chip, addr + i, buffer[i])) {
printf ("I2C read: I/O error\n");
i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);
return 1;
}
}
return 0;
}
static void wait_for_bb (void)
{
int timeout = 10;
u16 stat;
outw(0xFFFF, I2C_STAT); /* clear current interruts...*/
while ((stat = inw (I2C_STAT) & I2C_STAT_BB) && timeout--) {
outw (stat, I2C_STAT);
udelay (50000);
}
if (timeout <= 0) {
printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
inw (I2C_STAT));
}
outw(0xFFFF, I2C_STAT); /* clear delayed stuff*/
}
static u16 wait_for_pin (void)
{
u16 status;
int timeout = 10;
do {
udelay (1000);
status = inw (I2C_STAT);
} while ( !(status &
(I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
I2C_STAT_AL)) && timeout--);
if (timeout <= 0) {
printf ("timed out in wait_for_pin: I2C_STAT=%x\n",
inw (I2C_STAT));
outw(0xFFFF, I2C_STAT);
}
return status;
}
#endif /* CONFIG_DRIVER_OMAP24XX_I2C */
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