From bcd510db66838e8df0df05980b237f0e6b2adad7 Mon Sep 17 00:00:00 2001
From: Bertrik Sikken <bertrik@sikken.nl>
Date: Sat, 1 Aug 2009 14:58:52 +0000
Subject: Samsung YP-S3: implement button driver for the touch keys (and the
 hold/power switch)

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22093 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/target/arm/s5l8700/yps3/button-yps3.c | 146 +++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 firmware/target/arm/s5l8700/yps3/button-yps3.c

(limited to 'firmware/target')

diff --git a/firmware/target/arm/s5l8700/yps3/button-yps3.c b/firmware/target/arm/s5l8700/yps3/button-yps3.c
new file mode 100644
index 0000000000..74b5e130c3
--- /dev/null
+++ b/firmware/target/arm/s5l8700/yps3/button-yps3.c
@@ -0,0 +1,146 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2009 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 <stdbool.h>
+#include "config.h"
+
+#include "inttypes.h"
+#include "s5l8700.h"
+#include "button-target.h"
+
+/*  Button driver for the touch keys on the Samsung YP-S3
+
+    The exact controller is not known, but it is likely from Melfas.
+    
+    The protocol is as follows:
+    * the communication is done using three signals: DRDY, DCLK and DOUT
+    * in the idle state these signals are all high.
+    * when a key is touched or released, the key controller pulls down DRDY
+      and outputs the first bit of a 20-bit word on its DOUT signal.
+    * the CPU stores the bit, then acknowledges it by toggling the DCLK signal.
+    * the key controller prepares the next bit, then toggles its DRDY output,
+      unless all 20 bits have been transferred (in that case it stays high).
+    * the 20-bit word contains separate bits for each button, some fixed bits
+      and a bit indicating the number of keys pressed (modulo 2).
+ */
+
+
+void button_init_device(void)
+{
+    /* P0.5/P1.0 power switch input */
+    PCON0 &= ~(3 << 10);    
+    PCON1 &= ~0x0000000F;
+
+    /* P1.5 DATA, P1.6 DRDY inputs (touch key controller) */
+    PCON1 &= ~0x0FF00000; 
+    
+    /* P3.4 DCLK output (touch key controller) */
+    PCON3 = (PCON3 & ~0x000F0000) | 0x00010000;
+    PDAT3 |= (1 << 4);
+    
+    /* P4.3 hold switch input */
+    PCON4 &= ~0x0000F000;
+}
+
+static unsigned int tkey_read(void)
+{
+    static int value = 0;
+    int i;
+
+    /* check activity */
+    if (PDAT1 & (1 << 6)) {
+        return value;
+    }
+
+    /* get key bits */
+    value = 0;
+    for (i = 0; i < 10; i++) {
+        /* sample bit from falling edge of DRDY */
+        while ((PDAT1 & (1 << 6)) != 0);
+        value <<= 1;
+        if (PDAT1 & (1 << 5)) {
+            value |= 1;
+        }
+
+        /* acknowledge on DCLK */
+        PDAT3 &= ~(1 << 4);
+
+        /* sample bit from rising edge of DRDY */
+        while ((PDAT1 & (1 << 6)) == 0);
+        value <<= 1;
+        if (PDAT1 & (1 << 5)) {
+            value |= 1;
+        }
+
+        /* acknowledge on DCLK */
+        PDAT3 |= (1 << 4);
+    }
+    return value;
+}
+
+
+int button_read_device(void)
+{
+    int buttons = 0;
+    static unsigned int data;
+
+    /* hold switch */
+    if (button_hold()) {
+        return 0;
+    }
+
+    /* power button */
+    if (PDAT1 & (1 << 0)) {
+        buttons |= BUTTON_POWER;
+    }
+    
+    /* touch keys */
+    data = tkey_read();
+    if (data & (1 << 9)) {
+        buttons |= BUTTON_BACK;
+    }
+    if (data & (1 << 8)) {
+        buttons |= BUTTON_UP;
+    }
+    if (data & (1 << 7)) {
+        buttons |= BUTTON_MENU;
+    }
+    if (data & (1 << 6)) {
+        buttons |= BUTTON_LEFT;
+    }
+    if (data & (1 << 5)) {
+        buttons |= BUTTON_SELECT;
+    }
+    if (data & (1 << 4)) {
+        buttons |= BUTTON_RIGHT;
+    }
+    if (data & (1 << 3)) {
+        buttons |= BUTTON_DOWN;
+    }
+    
+    return buttons;
+}
+
+bool button_hold(void)
+{
+    return (PDAT4 & (1 << 3));
+}
+
-- 
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