1 files changed, 140 insertions, 0 deletions

diff --git a/firmware/target/arm/s3c2440/adc-s3c2440.c b/firmware/target/arm/s3c2440/adc-s3c2440.c
new file mode 100644
index 0000000000..fd5151a3bf
--- /dev/null
+++ b/firmware/target/arm/s3c2440/adc-s3c2440.c
@@ -0,0 +1,140 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2006 by Wade Brown
+ *
+ * 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 "cpu.h"
+#include "system.h"
+#include "adc.h"
+#include "adc-target.h"
+#include "kernel.h"
+
+static unsigned short adc_readings[NUM_ADC_CHANNELS];
+
+/* prototypes */
+static unsigned short __adc_read(int channel);
+static void adc_tick(void);
+
+void adc_init(void) 
+{
+    int i;
+
+    /* Turn on the ADC PCLK */
+    s3c_regset32(&CLKCON, 1<<15);
+
+    /* Set channel 0, normal mode, disable "start by read" */
+    ADCCON &= ~(0x3F);
+
+    /* No start delay.  Use normal conversion mode. */
+    ADCDLY = 0x1;
+
+    /* Set and enable the prescaler */
+    ADCCON = (ADCCON & ~(0xff<<6)) | (0x19<<6);
+    ADCCON |= (1<<14);
+
+    /* prefill the adc channels */
+    for (i = 0; i < NUM_ADC_CHANNELS; i++)
+    {
+        adc_readings[i] = __adc_read(i);
+    }
+
+    /* start at zero so when the tick starts it is at zero */
+    adc_readings[0] = __adc_read(0);
+
+    /* attach the adc reading to the tick */
+    tick_add_task(adc_tick);
+}
+
+/* Called to get the recent ADC reading */
+inline unsigned short adc_read(int channel)
+{
+    return adc_readings[channel];
+}
+
+/** 
+  * Read the ADC by polling
+  * @param channel The ADC channel to read
+  * @return 10bit reading from ADC channel or ADC_READ_ERROR if timeout
+  */
+static unsigned short __adc_read(int channel) 
+{
+    int i;
+
+    /* Set the channel */
+    ADCCON = (ADCCON & ~(0x7<<3)) | (channel<<3);
+
+    /* Start the conversion process */
+    ADCCON |= 0x1;
+
+    /* Wait for a low Enable_start */
+    for (i = 20000;;) 
+    {
+        if(0 == (ADCCON & 0x1)) 
+        {
+            break;
+        }
+        else 
+        {
+            i--;
+            if (0 == i) 
+            {
+                /* Ran out of time */
+                return ADC_READ_ERROR;
+            }
+        }
+    }
+
+    /* Wait for high End_of_Conversion */
+    for(i = 20000;;) 
+    {
+        if(ADCCON & (1<<15)) 
+        {
+            break;
+        }
+        else 
+        {
+            i--;
+            if(0 == i) 
+            {
+                /* Ran out of time */
+                return ADC_READ_ERROR;
+            }
+        }
+    }
+    return (ADCDAT0 & 0x3ff);
+}
+
+/* add this to the tick so that the ADC converts are done in the background */
+static void adc_tick(void)
+{
+    static unsigned channel;
+
+    /* Check if the End Of Conversion is set */
+    if (ADCCON & (1<<15)) 
+    {
+        adc_readings[channel] = (ADCDAT0 & 0x3FF);
+        if (++channel >= NUM_ADC_CHANNELS)
+        {
+            channel = 0;
+        }
+
+        /* setup the next conversion and start it*/
+        ADCCON = (ADCCON & ~(0x7<<3)) | (channel<<3) | 0x01;
+    }
+}
+