blob: 6530227ad7a3341d75943ec386163c7b0a2d9c96 [file] [log] [blame]
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Linus Nielsen Feltzing
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "lcd.h"
#include "sh7034.h"
#include "kernel.h"
#include "thread.h"
#include "debug.h"
#include "system.h"
#define PB13 0x2000
#define PB7 0x0080
#define PB5 0x0020
/* cute little functions, atomic read-modify-write */
#define SDA_LO __clear_bit_constant(7, &PBDRL)
#define SDA_HI __set_bit_constant(7, &PBDRL)
#define SDA_INPUT __clear_bit_constant(7, &PBIORL)
#define SDA_OUTPUT __set_bit_constant(7, &PBIORL)
#define SDA (PBDR & PB7)
#define SCL_INPUT __clear_bit_constant(13-8, &PBIORH)
#define SCL_OUTPUT __set_bit_constant(13-8, &PBIORH)
#define SCL_LO __clear_bit_constant(13-8, &PBDRH)
#define SCL_HI __set_bit_constant(13-8, &PBDRH)
#define SCL (PBDR & PB13)
/* arbitrary delay loop */
#define DELAY do { int _x; for(_x=0;_x<20;_x++);} while (0)
static struct mutex i2c_mtx;
void i2c_begin(void)
{
mutex_lock(&i2c_mtx);
}
void i2c_end(void)
{
mutex_unlock(&i2c_mtx);
}
void i2c_start(void)
{
SDA_OUTPUT;
SDA_HI;
SCL_HI;
SDA_LO;
DELAY;
SCL_LO;
}
void i2c_stop(void)
{
SDA_LO;
SCL_HI;
DELAY;
SDA_HI;
}
void i2c_init(void)
{
int i;
/* make PB5, PB7 & PB13 general I/O */
PBCR1 &= ~0x0c00; /* PB13 */
PBCR2 &= ~0xcc00; /* PB5 abd PB7 */
/* PB5 is "MAS enable". make it output and high */
__set_bit_constant(5, &PBIORL);
__set_bit_constant(5, &PBDRL);
/* Set the clock line PB13 to an output */
__set_bit_constant(13-8, &PBIORH);
SDA_OUTPUT;
SDA_HI;
SCL_LO;
for (i=0;i<3;i++)
i2c_stop();
}
void i2c_ack(int bit)
{
/* Here's the deal. The MAS is slow, and sometimes needs to wait
before it can receive the acknowledge. Therefore it forces the clock
low until it is ready. We need to poll the clock line until it goes
high before we release the ack. */
SCL_LO; /* Set the clock low */
if ( bit )
{
SDA_HI;
}
else
{
SDA_LO;
}
SCL_INPUT; /* Set the clock to input */
while(!SCL) /* and wait for the MAS to release it */
sleep_thread();
wake_up_thread();
DELAY;
SCL_OUTPUT;
SCL_LO;
}
int i2c_getack(void)
{
int ret = 1;
/* Here's the deal. The MAS is slow, and sometimes needs to wait
before it can send the acknowledge. Therefore it forces the clock
low until it is ready. We need to poll the clock line until it goes
high before we read the ack. */
#ifdef HAVE_I2C_LOW_FIRST
SDA_LO; /* First, discharge the data line */
#endif
SDA_INPUT; /* And set to input */
SCL_INPUT; /* Set the clock to input */
while(!SCL) /* and wait for the MAS to release it */
sleep_thread();
wake_up_thread();
if (SDA)
/* ack failed */
ret = 0;
SCL_OUTPUT;
SCL_LO;
SDA_HI;
SDA_OUTPUT;
return ret;
}
void 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;
}
SCL_HI;
SCL_LO;
}
SDA_HI;
}
unsigned char i2c_inb(int ack)
{
int i;
unsigned char byte = 0;
/* clock in each bit, MSB first */
for ( i=0x80; i; i>>=1 ) {
#ifdef HAVE_I2C_LOW_FIRST
/* Tricky business. Here we discharge the data line by driving it low
and then set it to input to see if it stays low or goes high */
SDA_LO; /* First, discharge the data line */
#endif
SDA_INPUT; /* And set to input */
SCL_HI;
if ( SDA )
byte |= i;
SCL_LO;
SDA_OUTPUT;
}
i2c_ack(ack);
return byte;
}
int i2c_write(int address, unsigned char* buf, int count )
{
int i,x=0;
i2c_start();
i2c_outb(address & 0xfe);
if (i2c_getack())
{
for (i=0; i<count; i++)
{
i2c_outb(buf[i]);
if (!i2c_getack())
{
x=-2;
break;
}
}
}
else
{
debugf("i2c_write() - no ack\n");
x=-1;
}
i2c_stop();
return x;
}
int i2c_read(int address, unsigned char* buf, int count )
{
int i,x=0;
i2c_start();
i2c_outb(address | 1);
if (i2c_getack()) {
for (i=0; i<count; i++) {
buf[i] = i2c_inb(0);
}
}
else
x=-1;
i2c_stop();
return x;
}