S5L8700: Implement ADC driver

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21734 a1c6a512-1295-4272-9138-f99709370657

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
new file mode 100644
index 0000000000..4407334099
--- /dev/null
+++ b/firmware/target/arm/s5l8700/adc-s5l8700.c
@@ -0,0 +1,94 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2009 by Bertrik Sikken
+ *
+ * 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 "inttypes.h"
+#include "s5l8700.h"
+#include "adc.h"
+#include "adc-target.h"
+#include "kernel.h"
+
+/*  Driver for the built-in ADC of the s5l8700
+
+    The ADC is put into standby mode after each conversion.
+ */
+
+#define ADC_PRESCALER   100     /* 1MHz ADC clock, assuming 100 MHz PCLK */
+#define ADC_DEFAULT (1<<14) |                   /* prescale enable */   \
+                    ((ADC_PRESCALER-1)<<6) |    /* prescaler */         \
+                    (0<<3) |                    /* sel_mux */           \
+                    (0<<2) |                    /* stdbm */             \
+                    (0<<1) |                    /* read_start */        \
+                    (0<<0)                      /* enable start */      \
+
+
+static struct mutex adc_mtx;
+static struct wakeup adc_wakeup;
+
+void INT_ADC(void)
+{
+    wakeup_signal(&adc_wakeup);
+}
+
+unsigned short adc_read(int channel)
+{
+    unsigned short data;
+
+    mutex_lock(&adc_mtx);
+    
+    /* set channel and start conversion */
+    ADCCON = ADC_DEFAULT | 
+             (channel << 3) |
+             (1 << 0);          /* enable start */
+    
+    /* wait for conversion */
+    wakeup_wait(&adc_wakeup, TIMEOUT_BLOCK);
+    
+    /* get the converted data */
+    data = ADCDAT0;
+    
+    /* put ADC back into standby */
+    ADCCON |= (1 << 2);
+
+    mutex_unlock(&adc_mtx);
+    
+    return data;
+}
+
+void adc_init(void)
+{
+    mutex_init(&adc_mtx);
+    wakeup_init(&adc_wakeup);
+
+    /* enable clock to ADC */
+    PWRCON &= ~(1 << 10);
+    
+    /* configure ADC and put in standby */
+    ADCCON = ADC_DEFAULT | (1 << 2);
+    
+    /* configure conversion delay (use default) */
+    ADCDLY = 0xFF;
+    
+    /* enable interrupt */
+    INTMSK |= (1 << 31);
+}
+