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/*
* (C) Copyright 2008-2011
* Logic Product Development, <www.logicpd.com>
* Peter Barada <peter.barada@logicpd.com>
*
* 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
*/
#include <common.h>
#include <command.h>
#include <asm/arch/cpu.h>
#include <asm/io.h>
#include <asm/arch/mux.h>
#include <asm/arch/sys_proto.h>
#include <asm/arch/clocks.h>
#include <asm/arch/mem.h>
#include <i2c.h>
#include <asm/mach-types.h>
#include "logic-i2c.h"
#define AT24_CHIP_ID 0xA0
#define AT24_ACCESS_WRITE 0
#define AT24_ACCESS_READ 1
#define AT24_DEVICE_ADDRESS(rw) (AT24_CHIP_ID | (rw & 1))
#define AT24_SIZE_MASK 0x7FF /* 2048 byte AT24C16 */
int at24_wakeup(void)
{
int i;
gpio_i2c_init(100000);
/* Need 9 clocks to wake up AT24 chips */
gpio_i2c_config_pin(GPIO_I2C_SCLK, GPIO_I2C_OUTPUT);
gpio_i2c_set_pin_level(GPIO_I2C_SCLK, 1);
for (i=0; i<10; ++i) {
udelay(100);
gpio_i2c_set_pin_level(GPIO_I2C_SCLK, 0);
udelay(100);
gpio_i2c_set_pin_level(GPIO_I2C_SCLK, 1);
}
/* We can't identify AT24 chips... */
return 0;
}
int at24_shutdown(void)
{
/* Restore GPIO_OE registers back to reset state (All input) */
gpio_i2c_config_pin(GPIO_I2C_SDATA, GPIO_I2C_INPUT);
gpio_i2c_config_pin(GPIO_I2C_SCLK, GPIO_I2C_INPUT);
/* Restore pins back to their intended use */
gpio_i2c_restore_pins();
return 0;
}
/* Send the offset to the AT24 chip */
static int at24_send_offset(u32 offset)
{
int sleeps = 100;
int timeout = 1000;
int err, i;
u32 byteoffset, sizemask, sentoffset;
do {
while (gpio_i2c_busy() && timeout--)
udelay(100);
sleeps--;
gpio_i2c_tx_start();
err = gpio_i2c_tx_byte(AT24_DEVICE_ADDRESS(AT24_ACCESS_WRITE));
/* If the eeprom is busy, reset the bus an start over */
if (err)
gpio_i2c_tx_stop();
if (err && !sleeps) {
/* NACK, return error */
return err;
}
} while (err);
/* Write the destination offset to the AT24 */
sizemask = AT24_SIZE_MASK;
sentoffset = offset & sizemask;
for (i=0; i<4; ++i) {
byteoffset = (sentoffset & 0xFF000000) >> 24;
if (sizemask & 0xFF000000) {
err = gpio_i2c_tx_byte(byteoffset);
if (err)
return err;
}
sentoffset <<= 8;
sizemask <<= 8;
}
return 0;
}
/* Read 'size' bytes from the AT88 at offset 'offset'; return 0 if good */
int at24_read(u32 offset, u8 *buf, u32 size)
{
int rx_mode;
int err, idx;
err = at24_send_offset(offset);
if (err)
return err;
gpio_i2c_tx_stop();
gpio_i2c_tx_start();
err = gpio_i2c_tx_byte(AT24_DEVICE_ADDRESS(AT24_ACCESS_READ));
if (err)
return err;
for (idx = 0; idx < size; ++idx) {
if (size == 1)
rx_mode = RX_MODE_ONE_BYTE;
else if (idx == (size - 1))
rx_mode = RX_MODE_LAST_BYTE;
else if (idx == (size - 2))
rx_mode = RX_MODE_NEXT_TO_LAST_BYTE;
else if (idx == 0)
rx_mode = RX_MODE_FIRST_BYTE;
else
rx_mode = RX_MODE_MIDDLE_BYTE;
err = gpio_i2c_rx_byte(&buf[idx], rx_mode);
if (err)
printf("%s:%d err idx %d\n", __FUNCTION__, __LINE__, idx);
}
gpio_i2c_tx_stop();
return err;
}
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