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u-boot/board/Marvell/common/i2c.c
Peter Tyser a056b1ce9e Marvell: i2c cleanup 
The following changes were made, primarily to bring the Marvell i2c
driver in line with U-Boot's current I2C API:
- Made i2c_init() globally accessible
- Made i2c_read() and i2c_write() return an integer
- Updated i2c_init() calls to pass in CONFIG_SYS_I2C_SLAVE in the
  offhand chance someone adds slave support in the future

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
2009-06-12 20:39:45 +02:00

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/*
* (C) Copyright 2000
* Wolfgang Denk, DENX Software Engineering, wd@denx.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
*
* Hacked for the DB64360 board by Ingo.Assmus@keymile.com
* extra improvments by Brain Waite
*/
#include <common.h>
#include <mpc8xx.h>
#include <malloc.h>
#include <i2c.h>
#include "../include/mv_gen_reg.h"
#include "../include/core.h"
#define MAX_I2C_RETRYS 10
#define I2C_DELAY 1000 /* Should be at least the # of MHz of Tclk */
#undef DEBUG_I2C
/*#define DEBUG_I2C*/
#ifdef DEBUG_I2C
#define DP(x) x
#else
#define DP(x)
#endif
/* Assuming that there is only one master on the bus (us) */
void i2c_init (int speed, int slaveaddr)
{
unsigned int n, m, freq, margin, power;
unsigned int actualN = 0, actualM = 0;
unsigned int control, status;
unsigned int minMargin = 0xffffffff;
unsigned int tclk = CONFIG_SYS_TCLK;
unsigned int i2cFreq = speed; /* 100000 max. Fast mode not supported */
DP (puts ("i2c_init\n"));
/* gtI2cMasterInit */
for (n = 0; n < 8; n++) {
for (m = 0; m < 16; m++) {
power = 2 << n; /* power = 2^(n+1) */
freq = tclk / (10 * (m + 1) * power);
if (i2cFreq > freq)
margin = i2cFreq - freq;
else
margin = freq - i2cFreq;
if (margin < minMargin) {
minMargin = margin;
actualN = n;
actualM = m;
}
}
}
DP (puts ("setup i2c bus\n"));
/* Setup bus */
/* gtI2cReset */
GT_REG_WRITE (I2C_SOFT_RESET, 0);
DP (puts ("udelay...\n"));
udelay (I2C_DELAY);
DP (puts ("set baudrate\n"));
GT_REG_WRITE (I2C_STATUS_BAUDE_RATE, (actualM << 3) | actualN);
GT_REG_WRITE (I2C_CONTROL, (0x1 << 2) | (0x1 << 6));
udelay (I2C_DELAY * 10);
DP (puts ("read control, baudrate\n"));
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
GT_REG_READ (I2C_CONTROL, &control);
}
static uchar i2c_start (void)
{ /* DB64360 checked -> ok */
unsigned int control, status;
int count = 0;
DP (puts ("i2c_start\n"));
/* Set the start bit */
/* gtI2cGenerateStartBit() */
GT_REG_READ (I2C_CONTROL, &control);
control |= (0x1 << 5); /* generate the I2C_START_BIT */
GT_REG_WRITE (I2C_CONTROL, control);
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count = 0;
while ((status & 0xff) != 0x08) {
udelay (I2C_DELAY);
if (count > 20) {
GT_REG_WRITE (I2C_CONTROL, (0x1 << 4)); /*stop */
return (status);
}
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
}
return (0);
}
static uchar i2c_select_device (uchar dev_addr, uchar read, int ten_bit)
{
unsigned int status, data, bits = 7;
int count = 0;
DP (puts ("i2c_select_device\n"));
/* Output slave address */
if (ten_bit) {
bits = 10;
}
data = (dev_addr << 1);
/* set the read bit */
data |= read;
GT_REG_WRITE (I2C_DATA, data);
/* assert the address */
RESET_REG_BITS (I2C_CONTROL, BIT3);
udelay (I2C_DELAY);
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count = 0;
while (((status & 0xff) != 0x40) && ((status & 0xff) != 0x18)) {
udelay (I2C_DELAY);
if (count > 20) {
GT_REG_WRITE (I2C_CONTROL, (0x1 << 4)); /*stop */
return (status);
}
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
}
if (bits == 10) {
printf ("10 bit I2C addressing not yet implemented\n");
return (0xff);
}
return (0);
}
static uchar i2c_get_data (uchar * return_data, int len)
{
unsigned int data, status = 0;
int count = 0;
DP (puts ("i2c_get_data\n"));
while (len) {
/* Get and return the data */
RESET_REG_BITS (I2C_CONTROL, (0x1 << 3));
udelay (I2C_DELAY * 5);
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
while ((status & 0xff) != 0x50) {
udelay (I2C_DELAY);
if (count > 2) {
GT_REG_WRITE (I2C_CONTROL, (0x1 << 4)); /*stop */
return 0;
}
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
}
GT_REG_READ (I2C_DATA, &data);
len--;
*return_data = (uchar) data;
return_data++;
}
RESET_REG_BITS (I2C_CONTROL, BIT2 | BIT3);
while ((status & 0xff) != 0x58) {
udelay (I2C_DELAY);
if (count > 200) {
GT_REG_WRITE (I2C_CONTROL, (0x1 << 4)); /*stop */
return (status);
}
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
}
GT_REG_WRITE (I2C_CONTROL, (0x1 << 4)); /* stop */
return (0);
}
static uchar i2c_write_data (unsigned int *data, int len)
{
unsigned int status;
int count = 0;
unsigned int temp;
unsigned int *temp_ptr = data;
DP (puts ("i2c_write_data\n"));
while (len) {
temp = (unsigned int) (*temp_ptr);
GT_REG_WRITE (I2C_DATA, temp);
RESET_REG_BITS (I2C_CONTROL, (0x1 << 3));
udelay (I2C_DELAY);
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
while ((status & 0xff) != 0x28) {
udelay (I2C_DELAY);
if (count > 20) {
GT_REG_WRITE (I2C_CONTROL, (0x1 << 4)); /*stop */
return (status);
}
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
}
len--;
temp_ptr++;
}
/* 11-14-2002 Paul Marchese */
/* Can't have the write issuing a stop command */
/* it's wrong to have a stop bit in read stream or write stream */
/* since we don't know if it's really the end of the command */
/* or whether we have just send the device address + offset */
/* we will push issuing the stop command off to the original */
/* calling function */
/* set the interrupt bit in the control register */
GT_REG_WRITE (I2C_CONTROL, (0x1 << 3));
udelay (I2C_DELAY * 10);
return (0);
}
/* 11-14-2002 Paul Marchese */
/* created this function to get the i2c_write() */
/* function working properly. */
/* function to write bytes out on the i2c bus */
/* this is identical to the function i2c_write_data() */
/* except that it requires a buffer that is an */
/* unsigned character array. You can't use */
/* i2c_write_data() to send an array of unsigned characters */
/* since the byte of interest ends up on the wrong end of the bus */
/* aah, the joys of big endian versus little endian! */
/* */
/* returns 0 = success */
/* anything other than zero is failure */
static uchar i2c_write_byte (unsigned char *data, int len)
{
unsigned int status;
int count = 0;
unsigned int temp;
unsigned char *temp_ptr = data;
DP (puts ("i2c_write_byte\n"));
while (len) {
/* Set and assert the data */
temp = *temp_ptr;
GT_REG_WRITE (I2C_DATA, temp);
RESET_REG_BITS (I2C_CONTROL, (0x1 << 3));
udelay (I2C_DELAY);
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
while ((status & 0xff) != 0x28) {
udelay (I2C_DELAY);
if (count > 20) {
GT_REG_WRITE (I2C_CONTROL, (0x1 << 4)); /*stop */
return (status);
}
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &status);
count++;
}
len--;
temp_ptr++;
}
/* Can't have the write issuing a stop command */
/* it's wrong to have a stop bit in read stream or write stream */
/* since we don't know if it's really the end of the command */
/* or whether we have just send the device address + offset */
/* we will push issuing the stop command off to the original */
/* calling function */
/* GT_REG_WRITE(I2C_CONTROL, (0x1 << 3) | (0x1 << 4));
GT_REG_WRITE(I2C_CONTROL, (0x1 << 4)); */
/* set the interrupt bit in the control register */
GT_REG_WRITE (I2C_CONTROL, (0x1 << 3));
udelay (I2C_DELAY * 10);
return (0);
}
static uchar
i2c_set_dev_offset (uchar dev_addr, unsigned int offset, int ten_bit,
int alen)
{
uchar status;
unsigned int table[2];
/* initialize the table of address offset bytes */
/* utilized for 2 byte address offsets */
/* NOTE: the order is high byte first! */
table[1] = offset & 0xff; /* low byte */
table[0] = offset / 0x100; /* high byte */
DP (puts ("i2c_set_dev_offset\n"));
status = i2c_select_device (dev_addr, 0, ten_bit);
if (status) {
#ifdef DEBUG_I2C
printf ("Failed to select device setting offset: 0x%02x\n",
status);
#endif
return status;
}
/* check the address offset length */
if (alen == 0)
/* no address offset */
return (0);
else if (alen == 1) {
/* 1 byte address offset */
status = i2c_write_data (&offset, 1);
if (status) {
#ifdef DEBUG_I2C
printf ("Failed to write data: 0x%02x\n", status);
#endif
return status;
}
} else if (alen == 2) {
/* 2 bytes address offset */
status = i2c_write_data (table, 2);
if (status) {
#ifdef DEBUG_I2C
printf ("Failed to write data: 0x%02x\n", status);
#endif
return status;
}
} else {
/* address offset unknown or not supported */
printf ("Address length offset %d is not supported\n", alen);
return 1;
}
return 0; /* sucessful completion */
}
int
i2c_read (uchar dev_addr, unsigned int offset, int alen, uchar * data,
int len)
{
uchar status = 0;
unsigned int i2cFreq = CONFIG_SYS_I2C_SPEED;
DP (puts ("i2c_read\n"));
/* set the i2c frequency */
i2c_init (i2cFreq, CONFIG_SYS_I2C_SLAVE);
status = i2c_start ();
if (status) {
#ifdef DEBUG_I2C
printf ("Transaction start failed: 0x%02x\n", status);
#endif
return status;
}
status = i2c_set_dev_offset (dev_addr, offset, 0, alen); /* send the slave address + offset */
if (status) {
#ifdef DEBUG_I2C
printf ("Failed to set slave address & offset: 0x%02x\n",
status);
#endif
return status;
}
/* set the i2c frequency again */
i2c_init (i2cFreq, CONFIG_SYS_I2C_SLAVE);
status = i2c_start ();
if (status) {
#ifdef DEBUG_I2C
printf ("Transaction restart failed: 0x%02x\n", status);
#endif
return status;
}
status = i2c_select_device (dev_addr, 1, 0); /* send the slave address */
if (status) {
#ifdef DEBUG_I2C
printf ("Address not acknowledged: 0x%02x\n", status);
#endif
return status;
}
status = i2c_get_data (data, len);
if (status) {
#ifdef DEBUG_I2C
printf ("Data not recieved: 0x%02x\n", status);
#endif
return status;
}
return 0;
}
/* 11-14-2002 Paul Marchese */
/* Function to set the I2C stop bit */
void i2c_stop (void)
{
GT_REG_WRITE (I2C_CONTROL, (0x1 << 4));
}
/* 11-14-2002 Paul Marchese */
/* I2C write function */
/* dev_addr = device address */
/* offset = address offset */
/* alen = length in bytes of the address offset */
/* data = pointer to buffer to read data into */
/* len = # of bytes to read */
/* */
/* returns 0 = succesful */
/* anything but zero is failure */
int
i2c_write (uchar dev_addr, unsigned int offset, int alen, uchar * data,
int len)
{
uchar status = 0;
unsigned int i2cFreq = CONFIG_SYS_I2C_SPEED;
DP (puts ("i2c_write\n"));
/* set the i2c frequency */
i2c_init (i2cFreq, CONFIG_SYS_I2C_SLAVE);
status = i2c_start (); /* send a start bit */
if (status) {
#ifdef DEBUG_I2C
printf ("Transaction start failed: 0x%02x\n", status);
#endif
return status;
}
status = i2c_set_dev_offset (dev_addr, offset, 0, alen); /* send the slave address + offset */
if (status) {
#ifdef DEBUG_I2C
printf ("Failed to set slave address & offset: 0x%02x\n",
status);
#endif
return status;
}
status = i2c_write_byte (data, len); /* write the data */
if (status) {
#ifdef DEBUG_I2C
printf ("Data not written: 0x%02x\n", status);
#endif
return status;
}
/* issue a stop bit */
i2c_stop ();
return 0;
}
/* 11-14-2002 Paul Marchese */
/* function to determine if an I2C device is present */
/* chip = device address of chip to check for */
/* */
/* returns 0 = sucessful, the device exists */
/* anything other than zero is failure, no device */
int i2c_probe (uchar chip)
{
/* We are just looking for an <ACK> back. */
/* To see if the device/chip is there */
#ifdef DEBUG_I2C
unsigned int i2c_status;
#endif
uchar status = 0;
unsigned int i2cFreq = CONFIG_SYS_I2C_SPEED;
DP (puts ("i2c_probe\n"));
/* set the i2c frequency */
i2c_init (i2cFreq, CONFIG_SYS_I2C_SLAVE);
status = i2c_start (); /* send a start bit */
if (status) {
#ifdef DEBUG_I2C
printf ("Transaction start failed: 0x%02x\n", status);
#endif
return (int) status;
}
status = i2c_set_dev_offset (chip, 0, 0, 0); /* send the slave address + no offset */
if (status) {
#ifdef DEBUG_I2C
printf ("Failed to set slave address: 0x%02x\n", status);
#endif
return (int) status;
}
#ifdef DEBUG_I2C
GT_REG_READ (I2C_STATUS_BAUDE_RATE, &i2c_status);
printf ("address %#x returned %#x\n", chip, i2c_status);
#endif
/* issue a stop bit */
i2c_stop ();
return 0; /* successful completion */
}
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