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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2008 by Michael Sevakis
*
* 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 "config.h"
#include "system.h"
#include "mc13783.h"
#include "adc-target.h"
#include "kernel.h"
/* Do this so we may read all channels in a single SPI message */
static const unsigned char reg_array[NUM_ADC_CHANNELS/2] =
{
MC13783_ADC2,
MC13783_ADC2,
MC13783_ADC2,
MC13783_ADC2,
MC13783_ADC2,
MC13783_ADC2,
MC13783_ADC2,
MC13783_ADC2,
};
static uint32_t channels[2][NUM_ADC_CHANNELS/2];
static struct wakeup adc_wake;
static struct mutex adc_mtx;
static long last_adc_read[2]; /* One for each input group */
/* Read 10-bit ADC channel */
unsigned short adc_read(int channel)
{
uint32_t data;
int input_select;
if ((unsigned)channel >= NUM_ADC_CHANNELS)
return ADC_READ_ERROR;
mutex_lock(&adc_mtx);
input_select = channel >> 3;
/* Limit the traffic through here */
if (TIME_AFTER(current_tick, last_adc_read[input_select]))
{
/* Keep enable, start conversion, increment from channel 0,
* increment from channel 4 */
uint32_t adc1 = MC13783_ADEN | MC13783_ASC | MC13783_ADA1w(0) |
MC13783_ADA2w(4);
if (input_select == 1)
adc1 |= MC13783_ADSEL; /* 2nd set of inputs */
/* Start conversion */
mc13783_write(MC13783_ADC1, adc1);
/* Wait for done signal */
wakeup_wait(&adc_wake, TIMEOUT_BLOCK);
/* Read all 8 channels that are converted - two channels in each
* word. */
mc13783_read_regset(reg_array, channels[input_select],
NUM_ADC_CHANNELS/2);
last_adc_read[input_select] = current_tick;
}
data = channels[input_select][channel & 7];
mutex_unlock(&adc_mtx);
/* Extract the bitfield depending on even or odd channel number */
return (channel & 1) ? MC13783_ADD2r(data) : MC13783_ADD1r(data);
}
/* Called when conversion is complete */
void adc_done(void)
{
wakeup_signal(&adc_wake);
}
void adc_init(void)
{
wakeup_init(&adc_wake);
mutex_init(&adc_mtx);
/* Init so first reads get data */
last_adc_read[0] = last_adc_read[1] = current_tick-1;
/* Enable increment-by-read, thermistor */
mc13783_write(MC13783_ADC0, MC13783_ADINC2 | MC13783_ADINC1 |
MC13783_RTHEN);
/* Enable ADC, set multi-channel mode */
mc13783_write(MC13783_ADC1, MC13783_ADEN);
/* Enable the ADCDONE interrupt - notifications are dispatched by
* event handler. */
mc13783_clear(MC13783_INTERRUPT_MASK0, MC13783_ADCDONE);
}
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