+++ /dev/null
-/*
- * Basic I2C functions
- *
- * Copyright (c) 2003 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
- *
- */
-
-#include <common.h>
-
-static void wait_for_bb (void);
-static u16 wait_for_pin (void);
-
-void i2c_init (int speed, int slaveadd)
-{
- u16 scl;
-
- if (inw (I2C_CON) & I2C_CON_EN) {
- outw (0, I2C_CON);
- udelay (5000);
- }
-
- /* 12MHz I2C module clock */
- outw (0, I2C_PSC);
- outw (I2C_CON_EN, I2C_CON);
- outw (0, I2C_SYSTEST);
- /* 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);
- scl = (12000000 / 2) / speed - 6;
- outw (scl, I2C_SCLL);
- outw (scl, I2C_SCLH);
- /* own address */
- outw (slaveadd, I2C_OA);
- outw (0, I2C_CNT);
- 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 */
- inw (I2C_IV);
- }
-
- 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);
- inw (I2C_IV);
- }
- }
- }
-
- return i2c_error;
-}
-
-static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
-{
- int i2c_error = 0;
- u16 status;
-
- /* 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 (30000);
- if (inw (I2C_STAT) & I2C_STAT_NACK) {
- i2c_error = 1;
- }
- } else {
- i2c_error = 1;
- }
-
- if (!i2c_error) {
- outw (I2C_CON_EN, I2C_CON);
- while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) {
- udelay (1000);
- /* have to read to clear intrrupt */
- inw (I2C_IV);
- }
- }
-
- return i2c_error;
-}
-
-int i2c_probe (uchar chip)
-{
- int res = 1;
-
- 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 (2000);
- if (!(inw (I2C_STAT) & I2C_STAT_NACK)) {
- res = 0;
- } else {
- outw (inw (I2C_CON) | I2C_CON_STP, I2C_CON);
- udelay (20);
- wait_for_bb ();
- }
-
- 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 (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_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 (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
- return 1;
- }
- }
-
- return 0;
-}
-
-static void wait_for_bb (void)
-{
- int timeout = 10;
-
- while ((inw (I2C_STAT) & I2C_STAT_BB) && timeout--) {
- inw (I2C_IV);
- udelay (1000);
- }
-
- if (timeout <= 0) {
- printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
- inw (I2C_STAT));
- }
-}
-
-static u16 wait_for_pin (void)
-{
- u16 status, iv;
- int timeout = 10;
-
- do {
- udelay (1000);
- status = inw (I2C_STAT);
- iv = inw (I2C_IV);
- } while (!iv &&
- !(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));
- }
-
- return status;
-}
projects / u-boot / commitdiff