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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2009 by Bertrik Sikken
*
* 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 "system.h"
#include "kernel.h"
#include "i2c-s5l8700.h"
/* Driver for the s5l8700 built-in I2C controller in master mode
Both the i2c_read and i2c_write function take the following arguments:
* slave, the address of the i2c slave device to read from / write to
* address, optional sub-address in the i2c slave (unused if -1)
* len, number of bytes to be transfered
* data, pointer to data to be transfered
A return value < 0 indicates an error.
Note:
* blocks the calling thread for the entire duraton of the i2c transfer but
uses wakeup_wait/wakeup_signal to allow other threads to run.
* ACK from slave is not checked, so functions never return an error
*/
static struct mutex i2c_mtx;
void i2c_init(void)
{
mutex_init(&i2c_mtx);
/* enable I2C pins */
PCON10 = (2 << 2) |
(2 << 0);
/* enable I2C clock */
PWRCON &= ~(1 << 5);
/* initial config */
IICADD = 0;
IICCON = (1 << 7) | /* ACK_GEN */
(0 << 6) | /* CLKSEL = PCLK/16 */
(1 << 5) | /* INT_EN */
(1 << 4) | /* IRQ clear */
(7 << 0); /* CK_REG */
/* serial output on */
IICSTAT = (1 << 4);
}
int i2c_write(unsigned char slave, int address, int len, const unsigned char *data)
{
mutex_lock(&i2c_mtx);
long timeout = current_tick + HZ / 50;
/* START */
IICDS = slave & ~1;
IICSTAT = 0xF0;
IICCON = 0xB7;
while ((IICCON & 0x10) == 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 1;
}
if (address >= 0) {
/* write address */
IICDS = address;
IICCON = 0xB7;
while ((IICCON & 0x10) == 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 2;
}
}
/* write data */
while (len--) {
IICDS = *data++;
IICCON = 0xB7;
while ((IICCON & 0x10) == 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 4;
}
}
/* STOP */
IICSTAT = 0xD0;
IICCON = 0xB7;
while ((IICSTAT & (1 << 5)) != 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 5;
}
mutex_unlock(&i2c_mtx);
return 0;
}
int i2c_read(unsigned char slave, int address, int len, unsigned char *data)
{
mutex_lock(&i2c_mtx);
long timeout = current_tick + HZ / 50;
if (address >= 0) {
/* START */
IICDS = slave & ~1;
IICSTAT = 0xF0;
IICCON = 0xB7;
while ((IICCON & 0x10) == 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 1;
}
/* write address */
IICDS = address;
IICCON = 0xB7;
while ((IICCON & 0x10) == 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 2;
}
}
/* (repeated) START */
IICDS = slave | 1;
IICSTAT = 0xB0;
IICCON = 0xB7;
while ((IICCON & 0x10) == 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 3;
}
while (len--) {
IICCON = (len == 0) ? 0x37 : 0xB7; /* NACK or ACK */
while ((IICCON & 0x10) == 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 4;
}
*data++ = IICDS;
}
/* STOP */
IICSTAT = 0x90;
IICCON = 0xB7;
while ((IICSTAT & (1 << 5)) != 0)
if (TIME_AFTER(current_tick, timeout))
{
mutex_unlock(&i2c_mtx);
return 5;
}
mutex_unlock(&i2c_mtx);
return 0;
}
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