b12c69bac7
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17100 a1c6a512-1295-4272-9138-f99709370657
111 lines
3.3 KiB
C
111 lines
3.3 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2008 by Michael Sevakis
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "config.h"
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#include "system.h"
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#include "mc13783.h"
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#include "adc-target.h"
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#include "kernel.h"
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/* Do this so we may read all channels in a single SPI message */
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static const unsigned char reg_array[NUM_ADC_CHANNELS/2] =
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{
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MC13783_ADC2,
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MC13783_ADC2,
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MC13783_ADC2,
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MC13783_ADC2,
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MC13783_ADC2,
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MC13783_ADC2,
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MC13783_ADC2,
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MC13783_ADC2,
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};
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static uint32_t channels[2][NUM_ADC_CHANNELS/2];
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static struct wakeup adc_wake;
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static struct mutex adc_mtx;
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static long last_adc_read[2]; /* One for each input group */
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/* Read 10-bit ADC channel */
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unsigned short adc_read(int channel)
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{
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uint32_t data;
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int input_select;
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if ((unsigned)channel >= NUM_ADC_CHANNELS)
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return ADC_READ_ERROR;
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mutex_lock(&adc_mtx);
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input_select = channel >> 3;
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/* Limit the traffic through here */
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if (TIME_AFTER(current_tick, last_adc_read[input_select]))
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{
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/* Keep enable, start conversion, increment from channel 0,
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* increment from channel 4 */
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uint32_t adc1 = MC13783_ADEN | MC13783_ASC | MC13783_ADA1w(0) |
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MC13783_ADA2w(4);
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if (input_select == 1)
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adc1 |= MC13783_ADSEL; /* 2nd set of inputs */
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/* Start conversion */
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mc13783_write(MC13783_ADC1, adc1);
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/* Wait for done signal */
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wakeup_wait(&adc_wake, TIMEOUT_BLOCK);
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/* Read all 8 channels that are converted - two channels in each
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* word. */
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mc13783_read_regset(reg_array, channels[input_select],
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NUM_ADC_CHANNELS/2);
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last_adc_read[input_select] = current_tick;
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}
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data = channels[input_select][channel & 7];
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mutex_unlock(&adc_mtx);
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/* Extract the bitfield depending on even or odd channel number */
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return (channel & 1) ? MC13783_ADD2r(data) : MC13783_ADD1r(data);
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}
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/* Called when conversion is complete */
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void adc_done(void)
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{
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wakeup_signal(&adc_wake);
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}
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void adc_init(void)
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{
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wakeup_init(&adc_wake);
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mutex_init(&adc_mtx);
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/* Init so first reads get data */
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last_adc_read[0] = last_adc_read[1] = current_tick-1;
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/* Enable increment-by-read, thermistor */
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mc13783_write(MC13783_ADC0, MC13783_ADINC2 | MC13783_ADINC1 |
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MC13783_RTHEN);
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/* Enable ADC, set multi-channel mode */
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mc13783_write(MC13783_ADC1, MC13783_ADEN);
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/* Enable the ADCDONE interrupt - notifications are dispatched by
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* event handler. */
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mc13783_clear(MC13783_INTERRUPT_MASK0, MC13783_ADCDONE);
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}
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