+++ /dev/null
-/*
- * i2c Support for Atmel's AT91RM9200 Two-Wire Interface
- *
- * (c) Rick Bronson
- *
- * Borrowed heavily from original work by:
- * Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
- *
- * Modified to work with u-boot by (C) 2004 Gary Jennejohn garyj@denx.de
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
-*/
-#include <common.h>
-
-#ifdef CONFIG_HARD_I2C
-
-#include <i2c.h>
-#include <asm/io.h>
-#include <asm/arch/hardware.h>
-
-#include <at91rm9200_i2c.h>
-
-/* define DEBUG */
-
-/*
- * Poll the i2c status register until the specified bit is set.
- * Returns 0 if timed out (100 msec)
- */
-static short at91_poll_status(AT91PS_TWI twi, unsigned long bit) {
- int loop_cntr = 10000;
- do {
- udelay(10);
- } while (!(twi->TWI_SR & bit) && (--loop_cntr > 0));
-
- return (loop_cntr > 0);
-}
-
-/*
- * Generic i2c master transfer entrypoint
- *
- * rw == 1 means that this is a read
- */
-static int
-at91_xfer(unsigned char chip, unsigned int addr, int alen,
- unsigned char *buffer, int len, int rw)
-{
- AT91PS_TWI twi = (AT91PS_TWI) AT91_TWI_BASE;
- int length;
- unsigned char *buf;
- /* Set the TWI Master Mode Register */
- twi->TWI_MMR = (chip << 16) | (alen << 8)
- | ((rw == 1) ? AT91C_TWI_MREAD : 0);
-
- /* Set TWI Internal Address Register with first messages data field */
- if (alen > 0)
- twi->TWI_IADR = addr;
-
- length = len;
- buf = buffer;
- if (length && buf) { /* sanity check */
- if (rw) {
- twi->TWI_CR = AT91C_TWI_START;
- while (length--) {
- if (!length)
- twi->TWI_CR = AT91C_TWI_STOP;
- /* Wait until transfer is finished */
- if (!at91_poll_status(twi, AT91C_TWI_RXRDY)) {
- debug ("at91_i2c: timeout 1\n");
- return 1;
- }
- *buf++ = twi->TWI_RHR;
- }
- if (!at91_poll_status(twi, AT91C_TWI_TXCOMP)) {
- debug ("at91_i2c: timeout 2\n");
- return 1;
- }
- } else {
- twi->TWI_CR = AT91C_TWI_START;
- while (length--) {
- twi->TWI_THR = *buf++;
- if (!length)
- twi->TWI_CR = AT91C_TWI_STOP;
- if (!at91_poll_status(twi, AT91C_TWI_TXRDY)) {
- debug ("at91_i2c: timeout 3\n");
- return 1;
- }
- }
- /* Wait until transfer is finished */
- if (!at91_poll_status(twi, AT91C_TWI_TXCOMP)) {
- debug ("at91_i2c: timeout 4\n");
- return 1;
- }
- }
- }
- return 0;
-}
-
-int
-i2c_probe(unsigned char chip)
-{
- unsigned char buffer[1];
-
- return at91_xfer(chip, 0, 0, buffer, 1, 1);
-}
-
-int
-i2c_read (unsigned char chip, unsigned int addr, int alen,
- unsigned char *buffer, int len)
-{
-#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
- /* we only allow one address byte */
- if (alen > 1)
- return 1;
- /* XXX assume an ATMEL AT24C16 */
- if (alen == 1) {
-#if 0 /* EEPROM code already sets this correctly */
- chip |= (addr >> 8) & 0xff;
-#endif
- addr = addr & 0xff;
- }
-#endif
- return at91_xfer(chip, addr, alen, buffer, len, 1);
-}
-
-int
-i2c_write(unsigned char chip, unsigned int addr, int alen,
- unsigned char *buffer, int len)
-{
-#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
- int i;
- unsigned char *buf;
-
- /* we only allow one address byte */
- if (alen > 1)
- return 1;
- /* XXX assume an ATMEL AT24C16 */
- if (alen == 1) {
- buf = buffer;
- /* do single byte writes */
- for (i = 0; i < len; i++) {
-#if 0 /* EEPROM code already sets this correctly */
- chip |= (addr >> 8) & 0xff;
-#endif
- addr = addr & 0xff;
- if (at91_xfer(chip, addr, alen, buf++, 1, 0))
- return 1;
- addr++;
- }
- return 0;
- }
-#endif
- return at91_xfer(chip, addr, alen, buffer, len, 0);
-}
-
-/*
- * Main initialization routine
- */
-void
-i2c_init(int speed, int slaveaddr)
-{
- AT91PS_TWI twi = (AT91PS_TWI) AT91_TWI_BASE;
-
- *AT91C_PIOA_PDR = AT91C_PA25_TWD | AT91C_PA26_TWCK;
- *AT91C_PIOA_ASR = AT91C_PA25_TWD | AT91C_PA26_TWCK;
- *AT91C_PIOA_MDER = AT91C_PA25_TWD | AT91C_PA26_TWCK;
- *AT91C_PMC_PCER = 1 << AT91C_ID_TWI; /* enable peripheral clock */
-
- twi->TWI_IDR = 0x3ff; /* Disable all interrupts */
- twi->TWI_CR = AT91C_TWI_SWRST; /* Reset peripheral */
- twi->TWI_CR = AT91C_TWI_MSEN | AT91C_TWI_SVDIS; /* Set Master mode */
-
- /* Here, CKDIV = 1 and CHDIV=CLDIV ==> CLDIV = CHDIV = 1/4*((Fmclk/FTWI) -6) */
- twi->TWI_CWGR = AT91C_TWI_CKDIV1 | AT91C_TWI_CLDIV3 | (AT91C_TWI_CLDIV3 << 8);
-
- debug ("Found AT91 i2c\n");
- return;
-}
-
-#endif /* CONFIG_HARD_I2C */
projects / u-boot / blobdiff