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Diffstat (limited to 'firmware/target/arm/s5l8700/adc-s5l8700.c')
-rw-r--r--firmware/target/arm/s5l8700/adc-s5l8700.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/firmware/target/arm/s5l8700/adc-s5l8700.c b/firmware/target/arm/s5l8700/adc-s5l8700.c
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1/***************************************************************************
2 * __________ __ ___.
3 * Open \______ \ ____ ____ | | _\_ |__ _______ ___
4 * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5 * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6 * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
7 * \/ \/ \/ \/ \/
8 * $Id$
9 *
10 * Copyright (C) 2009 by Bertrik Sikken
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version 2
15 * of the License, or (at your option) any later version.
16 *
17 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
18 * KIND, either express or implied.
19 *
20 ****************************************************************************/
21
22#include "config.h"
23
24#include "inttypes.h"
25#include "s5l8700.h"
26#include "adc.h"
27#include "adc-target.h"
28#include "kernel.h"
29
30/* Driver for the built-in ADC of the s5l8700
31
32 The ADC is put into standby mode after each conversion.
33 */
34
35#define ADC_PRESCALER 100 /* 1MHz ADC clock, assuming 100 MHz PCLK */
36#define ADC_DEFAULT (1<<14) | /* prescale enable */ \
37 ((ADC_PRESCALER-1)<<6) | /* prescaler */ \
38 (0<<3) | /* sel_mux */ \
39 (0<<2) | /* stdbm */ \
40 (0<<1) | /* read_start */ \
41 (0<<0) /* enable start */ \
42
43
44static struct mutex adc_mtx;
45static struct wakeup adc_wakeup;
46
47void INT_ADC(void)
48{
49 wakeup_signal(&adc_wakeup);
50}
51
52unsigned short adc_read(int channel)
53{
54 unsigned short data;
55
56 mutex_lock(&adc_mtx);
57
58 /* set channel and start conversion */
59 ADCCON = ADC_DEFAULT |
60 (channel << 3) |
61 (1 << 0); /* enable start */
62
63 /* wait for conversion */
64 wakeup_wait(&adc_wakeup, TIMEOUT_BLOCK);
65
66 /* get the converted data */
67 data = ADCDAT0;
68
69 /* put ADC back into standby */
70 ADCCON |= (1 << 2);
71
72 mutex_unlock(&adc_mtx);
73
74 return data;
75}
76
77void adc_init(void)
78{
79 mutex_init(&adc_mtx);
80 wakeup_init(&adc_wakeup);
81
82 /* enable clock to ADC */
83 PWRCON &= ~(1 << 10);
84
85 /* configure ADC and put in standby */
86 ADCCON = ADC_DEFAULT | (1 << 2);
87
88 /* configure conversion delay (use default) */
89 ADCDLY = 0xFF;
90
91 /* enable interrupt */
92 INTMSK |= (1 << 31);
93}
94