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-target.h"
  28
  29 /*  Button driver for the touch keys on the Samsung YP-S3
  30
  31     The exact controller is not known, but it is likely from Melfas.
  32
  33     The protocol is as follows:
  34     * the communication is done using three signals: DRDY, DCLK and DOUT
  35     * in the idle state these signals are all high.
  36     * when a key is touched or released, the key controller pulls down DRDY
  37       and outputs the first bit of a 20-bit word on its DOUT signal.
  38     * the CPU stores the bit, then acknowledges it by toggling the DCLK signal.
  39     * the key controller prepares the next bit, then toggles its DRDY output,
  40       unless all 20 bits have been transferred (in that case it stays high).
  41     * the 20-bit word contains separate bits for each button, some fixed bits
  42       and a bit indicating the number of keys pressed (modulo 2).
  43  */
  44
  45
  46 void button_init_device(void)
  47 {
  48     /* P0.5/P1.0 power switch input */
  49     PCON0 &= ~(3 << 10);
  50     PCON1 &= ~0x0000000F;
  51
  52     /* P1.3 headphones detect input */
  53     PCON1 &= ~0x0000F000;
  54
  55     /* P1.5 DATA, P1.6 DRDY inputs (touch key controller) */
  56     PCON1 &= ~0x0FF00000;
  57
  58     /* P3.4 DCLK output (touch key controller) */
  59     PCON3 = (PCON3 & ~0x000F0000) | 0x00010000;
  60     PDAT3 |= (1 << 4);
  61
  62     /* P4.3 hold switch input */
  63     PCON4 &= ~0x0000F000;
  64 }
  65
  66 static unsigned int tkey_read(void)
  67 {
  68     static int value = 0;
  69     int i;
  70
  71     /* check activity */
  72     if (PDAT1 & (1 << 6)) {
  73         return value;
  74     }
  75
  76     /* get key bits */
  77     value = 0;
  78     for (i = 0; i < 10; i++) {
  79         /* sample bit from falling edge of DRDY */
  80         while ((PDAT1 & (1 << 6)) != 0);
  81         value <<= 1;
  82         if (PDAT1 & (1 << 5)) {
  83             value |= 1;
  84         }
  85
  86         /* acknowledge on DCLK */
  87         PDAT3 &= ~(1 << 4);
  88
  89         /* sample bit from rising edge of DRDY */
  90         while ((PDAT1 & (1 << 6)) == 0);
  91         value <<= 1;
  92         if (PDAT1 & (1 << 5)) {
  93             value |= 1;
  94         }
  95
  96         /* acknowledge on DCLK */
  97         PDAT3 |= (1 << 4);
  98     }
  99     return value;
 100 }
 101
 102
 103 int button_read_device(void)
 104 {
 105     int buttons = 0;
 106     static unsigned int data;
 107
 108     /* hold switch */
 109     if (button_hold()) {
 110         return 0;
 111     }
 112
 113     /* power button */
 114     if (PDAT1 & (1 << 0)) {
 115         buttons |= BUTTON_POWER;
 116     }
 117
 118     /* touch keys */
 119     data = tkey_read();
 120     if (data & (1 << 9)) {
 121         buttons |= BUTTON_BACK;
 122     }
 123     if (data & (1 << 8)) {
 124         buttons |= BUTTON_UP;
 125     }
 126     if (data & (1 << 7)) {
 127         buttons |= BUTTON_MENU;
 128     }
 129     if (data & (1 << 6)) {
 130         buttons |= BUTTON_LEFT;
 131     }
 132     if (data & (1 << 5)) {
 133         buttons |= BUTTON_SELECT;
 134     }
 135     if (data & (1 << 4)) {
 136         buttons |= BUTTON_RIGHT;
 137     }
 138     if (data & (1 << 3)) {
 139         buttons |= BUTTON_DOWN;
 140     }
 141
 142     return buttons;
 143 }
 144
 145 bool button_hold(void)
 146 {
 147     return (PDAT4 & (1 << 3));
 148 }
 149
 150 bool headphones_inserted(void)
 151 {
 152     return ((PDAT1 & (1 << 3)) == 0);
 153 }
 154