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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 by Linus Nielsen Feltzing
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "cpu.h"
#include <stdbool.h>
#include <stdlib.h>
#include "debug.h"
#include "generic_i2c.h"
#define MAX_I2C_INTERFACES 5
static int i2c_num_ifs = 0;
static const struct i2c_interface *i2c_if[MAX_I2C_INTERFACES];
static void i2c_start(const struct i2c_interface *iface)
{
iface->sda_dir(true);
iface->sda_out(1);
iface->scl_out(1);
iface->delay(iface->delay_su_sta);
iface->sda_out(0);
iface->delay(iface->delay_hd_sta);
iface->scl_out(0);
iface->delay(iface->delay_hd_dat);
}
static void i2c_stop(const struct i2c_interface *iface)
{
iface->sda_dir(true);
iface->sda_out(0);
iface->delay(iface->delay_su_dat);
iface->scl_out(1);
iface->delay(iface->delay_su_sto);
iface->sda_out(1);
}
static void i2c_ack(const struct i2c_interface *iface, bool ack)
{
iface->sda_dir(true);
iface->sda_out(!ack);
iface->delay(iface->delay_su_dat);
iface->scl_out(1);
iface->delay(iface->delay_thigh);
iface->scl_out(0);
iface->delay(iface->delay_hd_dat);
}
static int i2c_getack(const struct i2c_interface *iface)
{
int ret = 1;
iface->sda_dir(false);
iface->delay(iface->delay_su_dat);
iface->scl_out(1);
iface->delay(iface->delay_thigh);
if (iface->sda_in())
ret = 0; /* ack failed */
iface->scl_out(0);
iface->delay(iface->delay_hd_dat);
return ret;
}
static unsigned char i2c_inb(const struct i2c_interface *iface, bool ack)
{
int i;
unsigned char byte = 0;
iface->sda_dir(false);
/* clock in each bit, MSB first */
for ( i=0x80; i; i>>=1 ) {
iface->delay(iface->delay_su_dat);
iface->scl_out(1);
iface->delay(iface->delay_thigh);
if (iface->sda_in())
byte |= i;
iface->scl_out(0);
iface->delay(iface->delay_hd_dat);
}
i2c_ack(iface, ack);
return byte;
}
static int i2c_outb(const struct i2c_interface *iface, unsigned char byte)
{
int i;
iface->sda_dir(true);
/* clock out each bit, MSB first */
for (i=0x80; i; i>>=1) {
iface->sda_out(i & byte);
iface->delay(iface->delay_su_dat);
iface->scl_out(1);
iface->delay(iface->delay_thigh);
iface->scl_out(0);
iface->delay(iface->delay_hd_dat);
}
return i2c_getack(iface);
}
int i2c_write_data(int bus_index, int bus_address, int address,
const unsigned char* buf, int count)
{
int i;
int ret = 0;
const struct i2c_interface *iface = i2c_if[bus_index];
i2c_start(iface);
if (!i2c_outb(iface, bus_address & 0xfe))
{
ret = -2;
goto end;
}
if (address != -1)
{
if (!i2c_outb(iface, address))
{
ret = -3;
goto end;
}
}
for(i = 0;i < count;i++)
{
if (!i2c_outb(iface, buf[i]))
{
ret = -4;
break;
}
}
end:
i2c_stop(iface);
return ret;
}
int i2c_read_data(int bus_index, int bus_address, int address,
unsigned char* buf, int count)
{
int i;
int ret = 0;
const struct i2c_interface *iface = i2c_if[bus_index];
if (address != -1)
{
i2c_start(iface);
if (!i2c_outb(iface, bus_address & 0xfe))
{
ret = -2;
goto end;
}
if (!i2c_outb(iface, address))
{
ret = -3;
goto end;
}
}
i2c_start(iface);
if (!i2c_outb(iface, bus_address | 1))
{
ret = -4;
goto end;
}
for(i = 0;i < count-1;i++)
buf[i] = i2c_inb(iface, true);
buf[i] = i2c_inb(iface, false);
end:
i2c_stop(iface);
return ret;
}
/* returns bus index which can be used as a handle, or <0 on error */
int i2c_add_node(const struct i2c_interface *iface)
{
int bus_index;
if (i2c_num_ifs == MAX_I2C_INTERFACES)
return -1;
bus_index = i2c_num_ifs++;
i2c_if[bus_index] = iface;
iface->scl_dir(true);
return bus_index;
}
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