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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 by Miika Pekkarinen
*
* 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 "system.h"
#include "logf.h"
#include "inttypes.h"
#include "sw_i2c.h"
/**
* I2C-functions are copied and ported from fmradio.c.
* later fixed, adapted and moved to a seperate file so they can be re-used
* by the rtc-ds1339c and later by the m:robe-100 code by Robert Kukla
*/
/* cute little functions, atomic read-modify-write */
#ifdef MROBE_100
/* SCL is GPIOC, 4 */
#define SCL (GPIOC_INPUT_VAL & 0x00000010)
#define SCL_OUT_LO GPIOC_OUTPUT_VAL&=~0x00000010
#define SCL_LO GPIOC_OUTPUT_EN |= 0x00000010
#define SCL_HI GPIOC_OUTPUT_EN &=~0x00000010
/* SDA is GPIOC, 5 */
#define SDA (GPIOC_INPUT_VAL & 0x00000020)
#define SDA_OUT_LO GPIOC_OUTPUT_VAL&=~0x00000020
#define SDA_LO GPIOC_OUTPUT_EN |= 0x00000020
#define SDA_HI GPIOC_OUTPUT_EN &=~0x00000020
#define DELAY do { volatile int _x; for(_x=0;_x<22;_x++);} while(0)
#else
/* SCL is GPIO, 12 */
#define SCL ( 0x00001000 & GPIO_READ)
#define SCL_OUT_LO and_l(~0x00001000, &GPIO_OUT)
#define SCL_LO or_l( 0x00001000, &GPIO_ENABLE)
#define SCL_HI and_l(~0x00001000, &GPIO_ENABLE)
/* SDA is GPIO1, 13 */
#define SDA ( 0x00002000 & GPIO1_READ)
#define SDA_OUT_LO and_l(~0x00002000, &GPIO1_OUT)
#define SDA_LO or_l( 0x00002000, &GPIO1_ENABLE)
#define SDA_HI and_l(~0x00002000, &GPIO1_ENABLE)
/* delay loop to achieve 400kHz at 120MHz CPU frequency */
#define DELAY \
({ \
int _x_; \
asm volatile ( \
"move.l #21, %[_x_] \r\n" \
"1: \r\n" \
"subq.l #1, %[_x_] \r\n" \
"bhi.b 1b \r\n" \
: [_x_]"=&d"(_x_) \
); \
})
#endif
void sw_i2c_init(void)
{
#ifndef MROBE_100
or_l(0x00001000, &GPIO_FUNCTION);
or_l(0x00002000, &GPIO1_FUNCTION);
#endif
SDA_HI;
SCL_HI;
SDA_OUT_LO;
SCL_OUT_LO;
}
/* in: C=? D=?
* out: C=L D=L
*/
static void sw_i2c_start(void)
{
SCL_LO;
DELAY;
SDA_HI;
DELAY;
SCL_HI;
DELAY;
SDA_LO;
DELAY;
SCL_LO;
}
/* in: C=L D=?
* out: C=H D=H
*/
static void sw_i2c_stop(void)
{
SDA_LO;
DELAY;
SCL_HI;
DELAY;
SDA_HI;
}
/* in: C=L D=H
* out: C=L D=L
*/
static void sw_i2c_ack(void)
{
SDA_LO;
DELAY;
SCL_HI;
DELAY;
SCL_LO;
}
/* in: C=L D=H
* out: C=L D=H
*/
static void sw_i2c_nack(void)
{
SDA_HI; /* redundant */
DELAY;
SCL_HI;
DELAY;
SCL_LO;
}
/* in: C=L D=?
* out: C=L D=H
*/
static bool sw_i2c_getack(void)
{
bool ret = true;
/* int count = 10; */
SDA_HI; /* sets to input */
DELAY;
SCL_HI;
DELAY;
/* while (SDA && count--) */
/* DELAY; */
if (SDA)
/* ack failed */
ret = false;
SCL_LO;
return ret;
}
/* in: C=L D=?
* out: C=L D=?
*/
static void sw_i2c_outb(unsigned char byte)
{
int i;
/* clock out each bit, MSB first */
for ( i=0x80; i; i>>=1 )
{
if ( i & byte )
SDA_HI;
else
SDA_LO;
DELAY;
SCL_HI;
DELAY;
SCL_LO;
}
}
/* in: C=L D=?
* out: C=L D=H
*/
static unsigned char sw_i2c_inb(void)
{
int i;
unsigned char byte = 0;
SDA_HI; /* sets to input */
/* clock in each bit, MSB first */
for ( i=0x80; i; i>>=1 )
{
DELAY;
do {
SCL_HI;
DELAY;
}
while(SCL==0); /* wait for any SCL clock stretching */
if ( SDA )
byte |= i;
SCL_LO;
}
return byte;
}
int sw_i2c_write(unsigned char chip, unsigned char location, unsigned char* buf, int count)
{
int i;
sw_i2c_start();
sw_i2c_outb((chip & 0xfe) | SW_I2C_WRITE);
if (!sw_i2c_getack())
{
sw_i2c_stop();
return -1;
}
#ifdef MROBE_100 /* does not use register addressing */
(void) location;
#else
sw_i2c_outb(location);
if (!sw_i2c_getack())
{
sw_i2c_stop();
return -2;
}
#endif
for (i=0; i<count; i++)
{
sw_i2c_outb(buf[i]);
if (!sw_i2c_getack())
{
sw_i2c_stop();
return -3;
}
}
sw_i2c_stop();
return 0;
}
int sw_i2c_read(unsigned char chip, unsigned char location, unsigned char* buf, int count)
{
int i;
#ifdef MROBE_100 /* does not use register addressing */
(void) location;
#else
sw_i2c_start();
sw_i2c_outb((chip & 0xfe) | SW_I2C_WRITE);
if (!sw_i2c_getack())
{
sw_i2c_stop();
return -1;
}
sw_i2c_outb(location);
if (!sw_i2c_getack())
{
sw_i2c_stop();
return -2;
}
#endif
sw_i2c_start();
sw_i2c_outb((chip & 0xfe) | SW_I2C_READ);
if (!sw_i2c_getack())
{
sw_i2c_stop();
return -3;
}
for (i=0; i<count-1; i++)
{
buf[i] = sw_i2c_inb();
sw_i2c_ack();
}
/* 1byte min */
buf[i] = sw_i2c_inb();
sw_i2c_nack();
sw_i2c_stop();
return 0;
}
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