firmware/target/arm/imx31/gigabeat-s/button-imx31.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006 by Linus Nielsen Feltzing
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19
  20 #include "config.h"
  21 #include "cpu.h"
  22 #include "system.h"
  23 #include "button.h"
  24 #include "backlight.h"
  25 #include "system.h"
  26 #include "backlight-target.h"
  27 #include "avic-imx31.h"
  28
  29 /* Most code in here is taken from the Linux BSP provided by Freescale
  30  * Copyright 2004-2006 Freescale Semiconductor, Inc. All Rights Reserved. */
  31
  32 static uint32_t int_btn = BUTTON_NONE;
  33 static bool hold_button     = false;
  34 static bool hold_button_old = false;
  35 #define _button_hold() (GPIO3_DR & 0x10)
  36
  37 static __attribute__((interrupt("IRQ"))) void KPP_HANDLER(void)
  38 {
  39     static const int key_mtx[5][3] =
  40     {
  41         { BUTTON_LEFT,   BUTTON_BACK, BUTTON_VOL_UP   },
  42         { BUTTON_UP,     BUTTON_MENU, BUTTON_VOL_DOWN },
  43         { BUTTON_DOWN,   BUTTON_NONE, BUTTON_PREV     },
  44         { BUTTON_RIGHT,  BUTTON_NONE, BUTTON_PLAY     },
  45         { BUTTON_SELECT, BUTTON_NONE, BUTTON_NEXT     },
  46     };
  47
  48     unsigned short reg_val;
  49     int col, row;
  50     int i;
  51     int button = BUTTON_NONE;
  52
  53     /* 1. Disable both (depress and release) keypad interrupts. */
  54     KPP_KPSR &= ~(KPP_KPSR_KRIE | KPP_KPSR_KDIE);
  55
  56     for (col = 0; col < 3; col++) /* Col */
  57     {
  58         /* 2. Write 1s to KPDR[10:8] setting column data to 1s */
  59         KPP_KPDR |= (0x7 << 8);
  60
  61         /* 3. Configure columns as totem pole outputs(for quick
  62          * discharging of keypad capacitance) */
  63         KPP_KPCR &= ~(0x7 << 8);
  64
  65         /* Give the columns time to discharge */
  66         for (i = 0; i < 256; i++)
  67             asm volatile ("");
  68
  69         /* 4. Configure columns as open-drain */
  70         KPP_KPCR |= (0x7 << 8);
  71
  72         /* 5. Write a single column to 0, others to 1.
  73          * 6. Sample row inputs and save data. Multiple key presses
  74          *    can be detected on a single column.
  75          * 7. Repeat steps 2 - 6 for remaining columns. */
  76
  77         /* Col bit starts at 8th bit in KPDR */
  78         KPP_KPDR &= ~(1 << (8 + col));
  79
  80         /* Delay added to avoid propagating the 0 from column to row
  81          * when scanning. */
  82         for (i = 0; i < 256; i++)
  83             asm volatile ("");
  84
  85         /* Read row input */
  86         reg_val = KPP_KPDR;
  87         for (row = 0; row < 5; row++)   /* sample row */
  88         {
  89             if (!(reg_val & (1 << row)))
  90                 button |= key_mtx[row][col];
  91         }
  92     }
  93
  94     /* 8. Return all columns to 0 in preparation for standby mode. */
  95     KPP_KPDR &= ~(0x7 << 8);
  96
  97     /* 9. Clear KPKD and KPKR status bit(s) by writing to a .1.,
  98      *    set the KPKR synchronizer chain by writing "1" to KRSS register,
  99      *    clear the KPKD synchronizer chain by writing "1" to KDSC register */
 100     KPP_KPSR = KPP_KPSR_KRSS | KPP_KPSR_KDSC | KPP_KPSR_KPKR | KPP_KPSR_KPKD;
 101
 102     /* 10. Re-enable the appropriate keypad interrupt(s) so that the KDIE
 103      *     detects a key hold condition, or the KRIE detects a key-release
 104      *     event. */
 105     if (button != BUTTON_NONE)
 106         KPP_KPSR |= KPP_KPSR_KRIE;
 107     else
 108         KPP_KPSR |= KPP_KPSR_KDIE;
 109
 110     int_btn = button;
 111 }
 112
 113 void button_init_device(void)
 114 {
 115     /* Enable keypad clock */
 116     CLKCTL_CGR1 |= (3 << 2*10);
 117
 118     /* 1. Enable number of rows in keypad (KPCR[4:0])
 119      *
 120      * Configure the rows/cols in KPP
 121      * LSB nybble in KPP is for 5 rows
 122      * MSB nybble in KPP is for 3 cols */
 123     KPP_KPCR |= 0x1f;
 124
 125     /* 2. Write 0's to KPDR[10:8] */
 126     KPP_KPDR &= ~(0x7 << 8);
 127
 128     /* 3. Configure the keypad columns as open-drain (KPCR[10:8]). */
 129     KPP_KPCR |= (0x7 << 8);
 130
 131     /* 4. Configure columns as output, rows as input (KDDR[10:8,4:0]) */
 132     KPP_KDDR = (KPP_KDDR | (0x7 << 8)) & ~0x1f;
 133
 134     /* 5. Clear the KPKD Status Flag and Synchronizer chain.
 135      * 6. Set the KDIE control bit, and set the KRIE control
 136      *    bit (to force immediate scan). */
 137     KPP_KPSR = KPP_KPSR_KRIE | KPP_KPSR_KDIE | KPP_KPSR_KRSS |
 138                KPP_KPSR_KDSC | KPP_KPSR_KPKR | KPP_KPSR_KPKD;
 139
 140     /* KPP IRQ at priority 3 */
 141     avic_enable_int(KPP, IRQ, 3, KPP_HANDLER);
 142 }
 143
 144 bool button_hold(void)
 145 {
 146     return _button_hold();
 147 }
 148
 149 int button_read_device(void)
 150 {
 151     /* Simple poll of GPIO status */
 152     hold_button = _button_hold();
 153
 154     /* Backlight hold handling */
 155     if (hold_button != hold_button_old)
 156     {
 157         hold_button_old = hold_button;
 158         backlight_hold_changed(hold_button);
 159     }
 160
 161     /* If hold, ignore any pressed button */
 162     return hold_button ? BUTTON_NONE : int_btn;
 163 }