adc-as3514.c : move to drivers

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@31629 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 67 insertions, 0 deletions

diff --git a/firmware/drivers/adc-as3514.c b/firmware/drivers/adc-as3514.c
new file mode 100644
index 0000000000..8c661eb133
--- /dev/null
+++ b/firmware/drivers/adc-as3514.c
@@ -0,0 +1,67 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2006 by Barry Wardell
+ *
+ * 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 "adc.h"
+#include "kernel.h"
+#include "ascodec.h"
+#include "as3514.h"
+
+/* Read 10-bit channel data */
+unsigned short adc_read(int channel)
+{
+    unsigned short data = 0;
+
+    if ((unsigned)channel >= NUM_ADC_CHANNELS)
+        return 0;
+
+    ascodec_lock();
+
+    /* Select channel */
+    if (ascodec_write(AS3514_ADC_0, (channel << 4)) >= 0)
+    {
+        unsigned char buf[2];
+
+        /*
+         * The AS3514 ADC will trigger an interrupt when the conversion
+         * is finished, if the corresponding enable bit in IRQ_ENRD2
+         * is set.
+         * Previously the code did not wait and this apparently did
+         * not pose any problems, but this should be more correct.
+         * Without the wait the data read back may be completely or
+         * partially (first one of the two bytes) stale.
+         */
+        ascodec_wait_adc_finished();
+
+
+        /* Read data */
+        if (ascodec_readbytes(AS3514_ADC_0, 2, buf) >= 0)
+        {
+            data = (((buf[0] & 0x3) << 8) | buf[1]);
+        }
+    }
+
+    ascodec_unlock();
+    
+    return data;
+}
+
+void adc_init(void)
+{
+}