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