firmware/target/arm/s5l8700/yps3/button-yps3.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2009 Bertrik Sikken
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include <stdbool.h>
  23 #include "config.h"
  24
  25 #include "inttypes.h"
  26 #include "s5l8700.h"
  27 #include "button.h"
  28 #include "button-target.h"
  29
  30 /*  Button driver for the touch keys on the Samsung YP-S3
  31
  32     The exact controller is not known, but it is likely from Melfas.
  33
  34     The protocol is as follows:
  35     * the communication is done using three signals: DRDY, DCLK and DOUT
  36     * in the idle state these signals are all high.
  37     * when a key is touched or released, the key controller pulls down DRDY
  38       and outputs the first bit of a 20-bit word on its DOUT signal.
  39     * the CPU stores the bit, then acknowledges it by toggling the DCLK signal.
  40     * the key controller prepares the next bit, then toggles its DRDY output,
  41       unless all 20 bits have been transferred (in that case it stays high).
  42     * the 20-bit word contains separate bits for each button, some fixed bits
  43       and a bit indicating the number of keys pressed (modulo 2).
  44  */
  45
  46
  47 void button_init_device(void)
  48 {
  49     /* P0.5/P1.0 power switch input */
  50     PCON0 &= ~(3 << 10);
  51     PCON1 &= ~0x0000000F;
  52
  53     /* P1.3 headphones detect input */
  54     PCON1 &= ~0x0000F000;
  55
  56     /* P1.5 DATA, P1.6 DRDY inputs (touch key controller) */
  57     PCON1 &= ~0x0FF00000;
  58
  59     /* P3.4 DCLK output (touch key controller) */
  60     PCON3 = (PCON3 & ~0x000F0000) | 0x00010000;
  61     PDAT3 |= (1 << 4);
  62
  63     /* P4.3 hold switch input */
  64     PCON4 &= ~0x0000F000;
  65 }
  66
  67 /* returns the raw 20-bit word from the touch key controller */
  68 static int tkey_read(void)
  69 {
  70     static int value = 0;
  71     int i;
  72
  73     /* check activity */
  74     if (PDAT1 & (1 << 6)) {
  75         return value;
  76     }
  77
  78     /* get key bits */
  79     value = 0;
  80     for (i = 0; i < 10; i++) {
  81         /* sample bit from falling edge of DRDY */
  82         while ((PDAT1 & (1 << 6)) != 0);
  83         value <<= 1;
  84         if (PDAT1 & (1 << 5)) {
  85             value |= 1;
  86         }
  87
  88         /* acknowledge on DCLK */
  89         PDAT3 &= ~(1 << 4);
  90
  91         /* sample bit from rising edge of DRDY */
  92         while ((PDAT1 & (1 << 6)) == 0);
  93         value <<= 1;
  94         if (PDAT1 & (1 << 5)) {
  95             value |= 1;
  96         }
  97
  98         /* acknowledge on DCLK */
  99         PDAT3 |= (1 << 4);
 100     }
 101     return value;
 102 }
 103
 104
 105 int button_read_device(void)
 106 {
 107     int buttons = 0;
 108     int tkey_data;
 109
 110     /* hold switch */
 111     if (button_hold()) {
 112         return 0;
 113     }
 114
 115     /* power button */
 116     if (PDAT1 & (1 << 0)) {
 117         buttons |= BUTTON_POWER;
 118     }
 119
 120     /* touch keys */
 121     tkey_data = tkey_read();
 122     if (tkey_data & (1 << 9)) {
 123         buttons |= BUTTON_BACK;
 124     }
 125     if (tkey_data & (1 << 8)) {
 126         buttons |= BUTTON_UP;
 127     }
 128     if (tkey_data & (1 << 7)) {
 129         buttons |= BUTTON_MENU;
 130     }
 131     if (tkey_data & (1 << 6)) {
 132         buttons |= BUTTON_LEFT;
 133     }
 134     if (tkey_data & (1 << 5)) {
 135         buttons |= BUTTON_SELECT;
 136     }
 137     if (tkey_data & (1 << 4)) {
 138         buttons |= BUTTON_RIGHT;
 139     }
 140     if (tkey_data & (1 << 3)) {
 141         buttons |= BUTTON_DOWN;
 142     }
 143
 144     return buttons;
 145 }
 146
 147 bool button_hold(void)
 148 {
 149     return (PDAT4 & (1 << 3));
 150 }
 151
 152 bool headphones_inserted(void)
 153 {
 154     return ((PDAT1 & (1 << 3)) == 0);
 155 }
 156