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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2007 by Jens Arnold
*
* 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 "hwcompat.h"
#include "kernel.h"
#include "adc.h"
#include "adc-target.h"
static struct mutex adc_mtx SHAREDBSS_ATTR;
/* used in the 2nd gen ADC interrupt */
static unsigned int_data;
static int int_status = -1;
unsigned short adc_scan(int channel)
{
unsigned short data = 0;
(void)channel; /* there is only one */
mutex_lock(&adc_mtx);
if ((IPOD_HW_REVISION >> 16) == 1)
{
int i, j;
unsigned pval = GPIOB_OUTPUT_VAL;
GPIOB_OUTPUT_VAL = pval | 0x04; /* B2 -> high */
for (i = 32; i > 0; --i);
GPIOB_OUTPUT_VAL = pval; /* B2 -> low */
for (i = 200; i > 0; --i);
for (j = 0; j < 8; j++)
{
GPIOB_OUTPUT_VAL = pval | 0x02; /* B1 -> high */
for (i = 8; i > 0; --i);
data = (data << 1) | ((GPIOB_INPUT_VAL & 0x08) >> 3);
GPIOB_OUTPUT_VAL = pval; /* B1 -> low */
for (i = 320; i > 0; --i);
}
}
else if ((IPOD_HW_REVISION >> 16) == 2)
{
int_status = 0;
GPIOB_INT_LEV |= 0x04; /* high active */
GPIOB_INT_EN |= 0x04; /* enable interrupt */
GPIOB_OUTPUT_VAL |= 0x0a; /* B1, B3 -> high: start conversion */
while (int_status >= 0)
yield();
data = int_data & 0xff;
}
mutex_unlock(&adc_mtx);
return data;
}
/* Used for 2nd gen only. Conversion can take several milliseconds there. */
void ipod_2g_adc_int(void)
{
if (GPIOB_INPUT_VAL & 0x04)
{
int_data = (int_data << 1) | ((GPIOB_INPUT_VAL & 0x10) >> 4);
GPIOB_OUTPUT_VAL &= ~0x0a; /* B1, B3 -> low */
/* B3 needs to be set low in the first call only, but then stays low
* anyway so no need for special handling */
}
else
{
if (++int_status > 8)
{
GPIOB_INT_EN &= ~0x04;
int_status = -1;
}
else
GPIOB_OUTPUT_VAL |= 0x02; /* B1 -> high */
}
GPIOB_INT_LEV ^= 0x04; /* toggle interrupt level */
GPIOB_INT_CLR = 0x04; /* acknowledge interrupt */
}
void adc_init(void)
{
mutex_init(&adc_mtx);
GPIOB_ENABLE |= 0x1e; /* enable B1..B4 */
if ((IPOD_HW_REVISION >> 16) == 1)
{
GPIOB_OUTPUT_EN = (GPIOB_OUTPUT_EN & ~0x08) | 0x16;
/* B1, B2, B4 -> output, B3 -> input */
GPIOB_OUTPUT_VAL = (GPIOB_OUTPUT_VAL & ~0x06) | 0x10;
/* B1, B2 -> low, B4 -> high */
}
else if ((IPOD_HW_REVISION >> 16) == 2)
{
GPIOB_OUTPUT_EN = (GPIOB_OUTPUT_EN & ~0x14) | 0x0a;
/* B1, B3 -> output, B2, B4 -> input */
GPIOB_OUTPUT_VAL &= ~0x0a; /* B1, B3 -> low */
while (GPIOB_INPUT_VAL & 0x04); /* wait for B2 == 0 */
}
}
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