linux/drivers/input/misc/dm355evm_keys.c
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   1/*
   2 * dm355evm_keys.c - support buttons and IR remote on DM355 EVM board
   3 *
   4 * Copyright (c) 2008 by David Brownell
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11#include <linux/kernel.h>
  12#include <linux/slab.h>
  13#include <linux/input.h>
  14#include <linux/input/sparse-keymap.h>
  15#include <linux/platform_device.h>
  16#include <linux/interrupt.h>
  17
  18#include <linux/mfd/dm355evm_msp.h>
  19#include <linux/module.h>
  20
  21
  22/*
  23 * The MSP430 firmware on the DM355 EVM monitors on-board pushbuttons
  24 * and an IR receptor used for the remote control.  When any key is
  25 * pressed, or its autorepeat kicks in, an event is sent.  This driver
  26 * read those events from the small (32 event) queue and reports them.
  27 *
  28 * Note that physically there can only be one of these devices.
  29 *
  30 * This driver was tested with firmware revision A4.
  31 */
  32struct dm355evm_keys {
  33        struct input_dev        *input;
  34        struct device           *dev;
  35};
  36
  37/* These initial keycodes can be remapped */
  38static const struct key_entry dm355evm_keys[] = {
  39        /*
  40         * Pushbuttons on the EVM board ... note that the labels for these
  41         * are SW10/SW11/etc on the PC board.  The left/right orientation
  42         * comes only from the firmware's documentation, and presumes the
  43         * power connector is immediately in front of you and the IR sensor
  44         * is to the right.  (That is, rotate the board counter-clockwise
  45         * by 90 degrees from the SW10/etc and "DM355 EVM" labels.)
  46         */
  47        { KE_KEY, 0x00d8, { KEY_OK } },         /* SW12 */
  48        { KE_KEY, 0x00b8, { KEY_UP } },         /* SW13 */
  49        { KE_KEY, 0x00e8, { KEY_DOWN } },       /* SW11 */
  50        { KE_KEY, 0x0078, { KEY_LEFT } },       /* SW14 */
  51        { KE_KEY, 0x00f0, { KEY_RIGHT } },      /* SW10 */
  52
  53        /*
  54         * IR buttons ... codes assigned to match the universal remote
  55         * provided with the EVM (Philips PM4S) using DVD code 0020.
  56         *
  57         * These event codes match firmware documentation, but other
  58         * remote controls could easily send more RC5-encoded events.
  59         * The PM4S manual was used in several cases to help select
  60         * a keycode reflecting the intended usage.
  61         *
  62         * RC5 codes are 14 bits, with two start bits (0x3 prefix)
  63         * and a toggle bit (masked out below).
  64         */
  65        { KE_KEY, 0x300c, { KEY_POWER } },      /* NOTE: docs omit this */
  66        { KE_KEY, 0x3000, { KEY_NUMERIC_0 } },
  67        { KE_KEY, 0x3001, { KEY_NUMERIC_1 } },
  68        { KE_KEY, 0x3002, { KEY_NUMERIC_2 } },
  69        { KE_KEY, 0x3003, { KEY_NUMERIC_3 } },
  70        { KE_KEY, 0x3004, { KEY_NUMERIC_4 } },
  71        { KE_KEY, 0x3005, { KEY_NUMERIC_5 } },
  72        { KE_KEY, 0x3006, { KEY_NUMERIC_6 } },
  73        { KE_KEY, 0x3007, { KEY_NUMERIC_7 } },
  74        { KE_KEY, 0x3008, { KEY_NUMERIC_8 } },
  75        { KE_KEY, 0x3009, { KEY_NUMERIC_9 } },
  76        { KE_KEY, 0x3022, { KEY_ENTER } },
  77        { KE_KEY, 0x30ec, { KEY_MODE } },       /* "tv/vcr/..." */
  78        { KE_KEY, 0x300f, { KEY_SELECT } },     /* "info" */
  79        { KE_KEY, 0x3020, { KEY_CHANNELUP } },  /* "up" */
  80        { KE_KEY, 0x302e, { KEY_MENU } },       /* "in/out" */
  81        { KE_KEY, 0x3011, { KEY_VOLUMEDOWN } }, /* "left" */
  82        { KE_KEY, 0x300d, { KEY_MUTE } },       /* "ok" */
  83        { KE_KEY, 0x3010, { KEY_VOLUMEUP } },   /* "right" */
  84        { KE_KEY, 0x301e, { KEY_SUBTITLE } },   /* "cc" */
  85        { KE_KEY, 0x3021, { KEY_CHANNELDOWN } },/* "down" */
  86        { KE_KEY, 0x3022, { KEY_PREVIOUS } },
  87        { KE_KEY, 0x3026, { KEY_SLEEP } },
  88        { KE_KEY, 0x3172, { KEY_REWIND } },     /* NOTE: docs wrongly say 0x30ca */
  89        { KE_KEY, 0x3175, { KEY_PLAY } },
  90        { KE_KEY, 0x3174, { KEY_FASTFORWARD } },
  91        { KE_KEY, 0x3177, { KEY_RECORD } },
  92        { KE_KEY, 0x3176, { KEY_STOP } },
  93        { KE_KEY, 0x3169, { KEY_PAUSE } },
  94};
  95
  96/*
  97 * Because we communicate with the MSP430 using I2C, and all I2C calls
  98 * in Linux sleep, we use a threaded IRQ handler.  The IRQ itself is
  99 * active low, but we go through the GPIO controller so we can trigger
 100 * on falling edges and not worry about enabling/disabling the IRQ in
 101 * the keypress handling path.
 102 */
 103static irqreturn_t dm355evm_keys_irq(int irq, void *_keys)
 104{
 105        static u16 last_event;
 106        struct dm355evm_keys *keys = _keys;
 107        const struct key_entry *ke;
 108        unsigned int keycode;
 109        int status;
 110        u16 event;
 111
 112        /* For simplicity we ignore INPUT_COUNT and just read
 113         * events until we get the "queue empty" indicator.
 114         * Reading INPUT_LOW decrements the count.
 115         */
 116        for (;;) {
 117                status = dm355evm_msp_read(DM355EVM_MSP_INPUT_HIGH);
 118                if (status < 0) {
 119                        dev_dbg(keys->dev, "input high err %d\n",
 120                                        status);
 121                        break;
 122                }
 123                event = status << 8;
 124
 125                status = dm355evm_msp_read(DM355EVM_MSP_INPUT_LOW);
 126                if (status < 0) {
 127                        dev_dbg(keys->dev, "input low err %d\n",
 128                                        status);
 129                        break;
 130                }
 131                event |= status;
 132                if (event == 0xdead)
 133                        break;
 134
 135                /* Press and release a button:  two events, same code.
 136                 * Press and hold (autorepeat), then release: N events
 137                 * (N > 2), same code.  For RC5 buttons the toggle bits
 138                 * distinguish (for example) "1-autorepeat" from "1 1";
 139                 * but PCB buttons don't support that bit.
 140                 *
 141                 * So we must synthesize release events.  We do that by
 142                 * mapping events to a press/release event pair; then
 143                 * to avoid adding extra events, skip the second event
 144                 * of each pair.
 145                 */
 146                if (event == last_event) {
 147                        last_event = 0;
 148                        continue;
 149                }
 150                last_event = event;
 151
 152                /* ignore the RC5 toggle bit */
 153                event &= ~0x0800;
 154
 155                /* find the key, or report it as unknown */
 156                ke = sparse_keymap_entry_from_scancode(keys->input, event);
 157                keycode = ke ? ke->keycode : KEY_UNKNOWN;
 158                dev_dbg(keys->dev,
 159                        "input event 0x%04x--> keycode %d\n",
 160                        event, keycode);
 161
 162                /* report press + release */
 163                input_report_key(keys->input, keycode, 1);
 164                input_sync(keys->input);
 165                input_report_key(keys->input, keycode, 0);
 166                input_sync(keys->input);
 167        }
 168
 169        return IRQ_HANDLED;
 170}
 171
 172/*----------------------------------------------------------------------*/
 173
 174static int dm355evm_keys_probe(struct platform_device *pdev)
 175{
 176        struct dm355evm_keys    *keys;
 177        struct input_dev        *input;
 178        int                     irq;
 179        int                     error;
 180
 181        keys = devm_kzalloc(&pdev->dev, sizeof (*keys), GFP_KERNEL);
 182        if (!keys)
 183                return -ENOMEM;
 184
 185        input = devm_input_allocate_device(&pdev->dev);
 186        if (!input)
 187                return -ENOMEM;
 188
 189        keys->dev = &pdev->dev;
 190        keys->input = input;
 191
 192        input->name = "DM355 EVM Controls";
 193        input->phys = "dm355evm/input0";
 194
 195        input->id.bustype = BUS_I2C;
 196        input->id.product = 0x0355;
 197        input->id.version = dm355evm_msp_read(DM355EVM_MSP_FIRMREV);
 198
 199        error = sparse_keymap_setup(input, dm355evm_keys, NULL);
 200        if (error)
 201                return error;
 202
 203        /* REVISIT:  flush the event queue? */
 204
 205        /* set up "threaded IRQ handler" */
 206        irq = platform_get_irq(pdev, 0);
 207        if (irq < 0)
 208                return irq;
 209
 210        error = devm_request_threaded_irq(&pdev->dev, irq,
 211                                          NULL, dm355evm_keys_irq,
 212                                          IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 213                                          dev_name(&pdev->dev), keys);
 214        if (error)
 215                return error;
 216
 217        /* register */
 218        error = input_register_device(input);
 219        if (error)
 220                return error;
 221
 222        return 0;
 223}
 224
 225/* REVISIT:  add suspend/resume when DaVinci supports it.  The IRQ should
 226 * be able to wake up the system.  When device_may_wakeup(&pdev->dev), call
 227 * enable_irq_wake() on suspend, and disable_irq_wake() on resume.
 228 */
 229
 230/*
 231 * I2C is used to talk to the MSP430, but this platform device is
 232 * exposed by an MFD driver that manages I2C communications.
 233 */
 234static struct platform_driver dm355evm_keys_driver = {
 235        .probe          = dm355evm_keys_probe,
 236        .driver         = {
 237                .name   = "dm355evm_keys",
 238        },
 239};
 240module_platform_driver(dm355evm_keys_driver);
 241
 242MODULE_LICENSE("GPL");
 243