465 lines
12 KiB
C
465 lines
12 KiB
C
/*
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* (C) Copyright 2000
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* Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
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*
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* (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
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* Marius Groeger <mgroeger@sysgo.de>
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*
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* (C) Copyright 2003 Pengutronix e.K.
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* Robert Schwebel <r.schwebel@pengutronix.de>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*
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* Back ported to the 8xx platform (from the 8260 platform) by
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* Murray.Jensen@cmst.csiro.au, 27-Jan-01.
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*/
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/* FIXME: this file is PXA255 specific! What about other XScales? */
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#include <common.h>
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#ifdef CONFIG_HARD_I2C
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/*
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* - CFG_I2C_SPEED
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* - I2C_PXA_SLAVE_ADDR
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*/
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#include <asm/arch/hardware.h>
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#include <asm/arch/pxa-regs.h>
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#include <i2c.h>
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/*#define DEBUG_I2C 1 /###* activate local debugging output */
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#define I2C_PXA_SLAVE_ADDR 0x1 /* slave pxa unit address */
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#define I2C_ICR_INIT (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE)
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#define I2C_ISR_INIT 0x7FF
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#ifdef DEBUG_I2C
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#define PRINTD(x) printf x
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#else
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#define PRINTD(x)
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#endif
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/* Shall the current transfer have a start/stop condition? */
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#define I2C_COND_NORMAL 0
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#define I2C_COND_START 1
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#define I2C_COND_STOP 2
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/* Shall the current transfer be ack/nacked or being waited for it? */
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#define I2C_ACKNAK_WAITACK 1
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#define I2C_ACKNAK_SENDACK 2
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#define I2C_ACKNAK_SENDNAK 4
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/* Specify who shall transfer the data (master or slave) */
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#define I2C_READ 0
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#define I2C_WRITE 1
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/* All transfers are described by this data structure */
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struct i2c_msg {
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u8 condition;
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u8 acknack;
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u8 direction;
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u8 data;
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};
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/**
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* i2c_pxa_reset: - reset the host controller
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*
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*/
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static void i2c_reset( void )
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{
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ICR &= ~ICR_IUE; /* disable unit */
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ICR |= ICR_UR; /* reset the unit */
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udelay(100);
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ICR &= ~ICR_IUE; /* disable unit */
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CKEN |= CKEN14_I2C; /* set the global I2C clock on */
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ISAR = I2C_PXA_SLAVE_ADDR; /* set our slave address */
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ICR = I2C_ICR_INIT; /* set control register values */
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ISR = I2C_ISR_INIT; /* set clear interrupt bits */
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ICR |= ICR_IUE; /* enable unit */
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udelay(100);
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}
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/**
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* i2c_isr_set_cleared: - wait until certain bits of the I2C status register
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* are set and cleared
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*
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* @return: 0 in case of success, 1 means timeout (no match within 10 ms).
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*/
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static int i2c_isr_set_cleared( unsigned long set_mask, unsigned long cleared_mask )
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{
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int timeout = 10000;
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while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){
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udelay( 10 );
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if( timeout-- < 0 ) return 0;
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}
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return 1;
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}
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/**
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* i2c_transfer: - Transfer one byte over the i2c bus
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*
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* This function can tranfer a byte over the i2c bus in both directions.
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* It is used by the public API functions.
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*
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* @return: 0: transfer successful
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* -1: message is empty
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* -2: transmit timeout
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* -3: ACK missing
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* -4: receive timeout
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* -5: illegal parameters
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* -6: bus is busy and couldn't be aquired
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*/
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int i2c_transfer(struct i2c_msg *msg)
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{
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int ret;
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if (!msg)
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goto transfer_error_msg_empty;
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switch(msg->direction) {
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case I2C_WRITE:
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/* check if bus is not busy */
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if (!i2c_isr_set_cleared(0,ISR_IBB))
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goto transfer_error_bus_busy;
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/* start transmission */
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ICR &= ~ICR_START;
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ICR &= ~ICR_STOP;
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IDBR = msg->data;
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if (msg->condition == I2C_COND_START) ICR |= ICR_START;
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if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP;
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if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK;
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if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
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ICR &= ~ICR_ALDIE;
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ICR |= ICR_TB;
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/* transmit register empty? */
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if (!i2c_isr_set_cleared(ISR_ITE,0))
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goto transfer_error_transmit_timeout;
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/* clear 'transmit empty' state */
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ISR |= ISR_ITE;
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/* wait for ACK from slave */
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if (msg->acknack == I2C_ACKNAK_WAITACK)
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if (!i2c_isr_set_cleared(0,ISR_ACKNAK))
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goto transfer_error_ack_missing;
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break;
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case I2C_READ:
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/* check if bus is not busy */
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if (!i2c_isr_set_cleared(0,ISR_IBB))
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goto transfer_error_bus_busy;
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/* start receive */
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ICR &= ~ICR_START;
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ICR &= ~ICR_STOP;
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if (msg->condition == I2C_COND_START) ICR |= ICR_START;
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if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP;
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if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK;
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if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
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ICR &= ~ICR_ALDIE;
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ICR |= ICR_TB;
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/* receive register full? */
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if (!i2c_isr_set_cleared(ISR_IRF,0))
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goto transfer_error_receive_timeout;
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msg->data = IDBR;
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/* clear 'receive empty' state */
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ISR |= ISR_IRF;
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break;
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default:
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goto transfer_error_illegal_param;
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}
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return 0;
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transfer_error_msg_empty:
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PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
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ret = -1; goto i2c_transfer_finish;
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transfer_error_transmit_timeout:
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PRINTD(("i2c_transfer: error: transmit timeout\n"));
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ret = -2; goto i2c_transfer_finish;
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transfer_error_ack_missing:
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PRINTD(("i2c_transfer: error: ACK missing\n"));
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ret = -3; goto i2c_transfer_finish;
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transfer_error_receive_timeout:
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PRINTD(("i2c_transfer: error: receive timeout\n"));
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ret = -4; goto i2c_transfer_finish;
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transfer_error_illegal_param:
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PRINTD(("i2c_transfer: error: illegal parameters\n"));
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ret = -5; goto i2c_transfer_finish;
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transfer_error_bus_busy:
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PRINTD(("i2c_transfer: error: bus is busy\n"));
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ret = -6; goto i2c_transfer_finish;
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i2c_transfer_finish:
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PRINTD(("i2c_transfer: ISR: 0x%04x\n",ISR));
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i2c_reset();
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return ret;
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}
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/* ------------------------------------------------------------------------ */
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/* API Functions */
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/* ------------------------------------------------------------------------ */
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void i2c_init(int speed, int slaveaddr)
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{
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#ifdef CFG_I2C_INIT_BOARD
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/* call board specific i2c bus reset routine before accessing the */
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/* environment, which might be in a chip on that bus. For details */
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/* about this problem see doc/I2C_Edge_Conditions. */
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i2c_init_board();
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#endif
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}
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/**
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* i2c_probe: - Test if a chip answers for a given i2c address
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*
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* @chip: address of the chip which is searched for
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* @return: 0 if a chip was found, -1 otherwhise
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*/
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int i2c_probe(uchar chip)
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{
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struct i2c_msg msg;
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i2c_reset();
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msg.condition = I2C_COND_START;
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msg.acknack = I2C_ACKNAK_WAITACK;
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msg.direction = I2C_WRITE;
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msg.data = (chip << 1) + 1;
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if (i2c_transfer(&msg)) return -1;
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msg.condition = I2C_COND_STOP;
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msg.acknack = I2C_ACKNAK_SENDNAK;
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msg.direction = I2C_READ;
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msg.data = 0x00;
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if (i2c_transfer(&msg)) return -1;
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return 0;
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}
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/**
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* i2c_read: - Read multiple bytes from an i2c device
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*
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* The higher level routines take into account that this function is only
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* called with len < page length of the device (see configuration file)
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*
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* @chip: address of the chip which is to be read
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* @addr: i2c data address within the chip
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* @alen: length of the i2c data address (1..2 bytes)
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* @buffer: where to write the data
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* @len: how much byte do we want to read
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* @return: 0 in case of success
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*/
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int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
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{
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struct i2c_msg msg;
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u8 addr_bytes[3]; /* lowest...highest byte of data address */
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int ret;
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PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
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i2c_reset();
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/* dummy chip address write */
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PRINTD(("i2c_read: dummy chip address write\n"));
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msg.condition = I2C_COND_START;
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msg.acknack = I2C_ACKNAK_WAITACK;
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msg.direction = I2C_WRITE;
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msg.data = (chip << 1);
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msg.data &= 0xFE;
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if ((ret=i2c_transfer(&msg))) return -1;
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/*
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* send memory address bytes;
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* alen defines how much bytes we have to send.
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*/
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/*addr &= ((1 << CFG_EEPROM_PAGE_WRITE_BITS)-1); */
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addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
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addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
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addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
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while (--alen >= 0) {
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PRINTD(("i2c_read: send memory word address byte %1d\n",alen));
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msg.condition = I2C_COND_NORMAL;
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msg.acknack = I2C_ACKNAK_WAITACK;
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msg.direction = I2C_WRITE;
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msg.data = addr_bytes[alen];
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if ((ret=i2c_transfer(&msg))) return -1;
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}
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/* start read sequence */
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PRINTD(("i2c_read: start read sequence\n"));
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msg.condition = I2C_COND_START;
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msg.acknack = I2C_ACKNAK_WAITACK;
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msg.direction = I2C_WRITE;
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msg.data = (chip << 1);
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msg.data |= 0x01;
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if ((ret=i2c_transfer(&msg))) return -1;
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/* read bytes; send NACK at last byte */
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while (len--) {
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if (len==0) {
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msg.condition = I2C_COND_STOP;
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msg.acknack = I2C_ACKNAK_SENDNAK;
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} else {
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msg.condition = I2C_COND_NORMAL;
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msg.acknack = I2C_ACKNAK_SENDACK;
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}
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msg.direction = I2C_READ;
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msg.data = 0x00;
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if ((ret=i2c_transfer(&msg))) return -1;
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*(buffer++) = msg.data;
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PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
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}
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i2c_reset();
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return 0;
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}
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/**
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* i2c_write: - Write multiple bytes to an i2c device
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*
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* The higher level routines take into account that this function is only
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* called with len < page length of the device (see configuration file)
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*
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* @chip: address of the chip which is to be written
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* @addr: i2c data address within the chip
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* @alen: length of the i2c data address (1..2 bytes)
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* @buffer: where to find the data to be written
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* @len: how much byte do we want to read
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* @return: 0 in case of success
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*/
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int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
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{
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struct i2c_msg msg;
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u8 addr_bytes[3]; /* lowest...highest byte of data address */
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PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
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i2c_reset();
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/* chip address write */
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PRINTD(("i2c_write: chip address write\n"));
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msg.condition = I2C_COND_START;
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msg.acknack = I2C_ACKNAK_WAITACK;
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msg.direction = I2C_WRITE;
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msg.data = (chip << 1);
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msg.data &= 0xFE;
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if (i2c_transfer(&msg)) return -1;
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/*
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* send memory address bytes;
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* alen defines how much bytes we have to send.
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*/
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addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
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addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
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addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
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while (--alen >= 0) {
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PRINTD(("i2c_write: send memory word address\n"));
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msg.condition = I2C_COND_NORMAL;
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msg.acknack = I2C_ACKNAK_WAITACK;
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msg.direction = I2C_WRITE;
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msg.data = addr_bytes[alen];
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if (i2c_transfer(&msg)) return -1;
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}
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/* write bytes; send NACK at last byte */
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while (len--) {
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PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
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if (len==0)
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msg.condition = I2C_COND_STOP;
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else
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msg.condition = I2C_COND_NORMAL;
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msg.acknack = I2C_ACKNAK_WAITACK;
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msg.direction = I2C_WRITE;
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msg.data = *(buffer++);
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if (i2c_transfer(&msg)) return -1;
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}
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i2c_reset();
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return 0;
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}
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uchar i2c_reg_read (uchar chip, uchar reg)
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{
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char buf;
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PRINTD(("i2c_reg_read(chip=0x%02x, reg=0x%02x)\n",chip,reg));
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i2c_read(chip, reg, 1, &buf, 1);
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return (buf);
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}
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void i2c_reg_write(uchar chip, uchar reg, uchar val)
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{
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PRINTD(("i2c_reg_write(chip=0x%02x, reg=0x%02x, val=0x%02x)\n",chip,reg,val));
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i2c_write(chip, reg, 1, &val, 1);
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}
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#endif /* CONFIG_HARD_I2C */
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