Fuzev2: Scrollwheel works like a charm :)

Move scrollwheel parsing function into separate file as it's reused.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25425 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 124 insertions, 0 deletions

diff --git a/firmware/target/arm/as3525/scrollwheel-as3525.c b/firmware/target/arm/as3525/scrollwheel-as3525.c
new file mode 100644
index 0000000000..a9e012a31f
--- /dev/null
+++ b/firmware/target/arm/as3525/scrollwheel-as3525.c
@@ -0,0 +1,124 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2009-2010 by Thomas Martitz
+ *
+ * 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 "button.h"
+#include "kernel.h"
+#include "backlight.h"
+
+void scrollwheel(unsigned int wheel_value)
+{
+#ifndef BOOTLOADER
+    /* current wheel values, parsed from dbop and the resulting button */
+    unsigned         btn             = BUTTON_NONE;
+    /* old wheel values */
+    static unsigned old_wheel_value = 0;
+    static unsigned old_btn         = BUTTON_NONE;
+
+    /*
+     * Getting BUTTON_REPEAT works like this: Remember when the btn value was
+     * posted to the button_queue last, and if it was recent enough, generate
+     * BUTTON_REPEAT
+     */
+    static long      last_wheel_post = 0;
+
+    /*
+     *  Providing wheel acceleration works as follows: We increment accel
+     * by 2 if the wheel was turned, and decrement it by 1 each tick
+     * (no matter if it was turned), that means: the longer and faster you turn,
+     * the higher accel will be. accel>>2 will actually posted to the button_queue
+     */
+    static int        accel = 0;
+    /* We only post every 4th action, as this matches better with the physical
+     * clicks of the wheel */
+    static int        counter = 0;
+    /* Read wheel 
+     * Bits 13 and 14 of DBOP_DIN change as follows (Gray Code):
+     * Clockwise rotation   00 -> 01 -> 11 -> 10 -> 00
+     * Counter-clockwise    00 -> 10 -> 11 -> 01 -> 00
+     *
+     * For easy look-up, actual wheel values act as indicies also,
+     * which is why the table seems to be not ordered correctly
+     */
+    static const unsigned char wheel_tbl[2][4] =
+    {
+        { 2, 0, 3, 1 }, /* Clockwise rotation */
+        { 1, 3, 0, 2 }, /* Counter-clockwise  */ 
+    };
+
+    if(button_hold())
+    {
+        accel  =  counter  = 0;
+        return;
+    }
+
+    if (old_wheel_value == wheel_tbl[0][wheel_value])
+        btn = BUTTON_SCROLL_FWD;
+    else if (old_wheel_value == wheel_tbl[1][wheel_value])
+        btn = BUTTON_SCROLL_BACK;
+    else if (old_wheel_value != wheel_value && accel > ACCEL_INCREMENT)
+    {   /* if no button is read and wheel_value changed, assume old_btn */
+        btn = old_btn;
+    }
+    /* else btn = BUTTON_NONE */
+
+    if (btn != BUTTON_NONE)
+    {
+        if (btn != old_btn)
+        {
+            /* direction reversals nullify acceleration and counters */
+            old_btn =  btn;
+            accel  =  counter  = 0;
+        }
+        /* wheel_delta will cause lists to jump over items,
+         * we want this for fast scrolling, but we must keep it accurate
+         * for slow scrolling */
+        int wheel_delta = 0;
+        /* generate BUTTON_REPEAT if quick enough, scroll slightly faster too*/
+        if (TIME_BEFORE(current_tick, last_wheel_post + WHEEL_REPEAT_INTERVAL))
+        {
+            btn |= BUTTON_REPEAT;
+            wheel_delta = accel>>ACCEL_SHIFT;
+        }
+
+        accel += ACCEL_INCREMENT;
+
+        /* the wheel is more reliable if we don't send every change,
+         * every WHEEL_COUNTER_DIVth is basically one "physical click" 
+         * which should make up 1 item in lists */
+        if (++counter >= WHEEL_COUNTER_DIV && queue_empty(&button_queue))
+        {
+            buttonlight_on();
+            backlight_on();
+            queue_post(&button_queue, btn, ((wheel_delta+1)<<24));
+            /* message posted - reset count and remember post */
+            counter = 0;
+            last_wheel_post = current_tick;
+        }
+    }
+    if (accel > 0)
+        accel--;
+
+    old_wheel_value = wheel_value;
+#else
+    (void)wheel_value
+#endif
+}