dm355evm_keys.c

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/*
 * dm355evm_keys.c - support buttons and IR remote on DM355 EVM board
 *
 * Copyright (c) 2008 by David Brownell
 *
 * 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.
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/input/sparse-keymap.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>

#include <linux/i2c/dm355evm_msp.h>
#include <linux/module.h>


/*
 * The MSP430 firmware on the DM355 EVM monitors on-board pushbuttons
 * and an IR receptor used for the remote control.  When any key is
 * pressed, or its autorepeat kicks in, an event is sent.  This driver
 * read those events from the small (32 event) queue and reports them.
 *
 * Note that physically there can only be one of these devices.
 *
 * This driver was tested with firmware revision A4.
 */
struct dm355evm_keys {
    struct input_dev    *input;
    struct device       *dev;
    int         irq;
};

/* These initial keycodes can be remapped */
static const struct key_entry dm355evm_keys[] = {
    /*
     * Pushbuttons on the EVM board ... note that the labels for these
     * are SW10/SW11/etc on the PC board.  The left/right orientation
     * comes only from the firmware's documentation, and presumes the
     * power connector is immediately in front of you and the IR sensor
     * is to the right.  (That is, rotate the board counter-clockwise
     * by 90 degrees from the SW10/etc and "DM355 EVM" labels.)
     */
    { KE_KEY, 0x00d8, { KEY_OK } },     /* SW12 */
    { KE_KEY, 0x00b8, { KEY_UP } },     /* SW13 */
    { KE_KEY, 0x00e8, { KEY_DOWN } },   /* SW11 */
    { KE_KEY, 0x0078, { KEY_LEFT } },   /* SW14 */
    { KE_KEY, 0x00f0, { KEY_RIGHT } },  /* SW10 */

    /*
     * IR buttons ... codes assigned to match the universal remote
     * provided with the EVM (Philips PM4S) using DVD code 0020.
     *
     * These event codes match firmware documentation, but other
     * remote controls could easily send more RC5-encoded events.
     * The PM4S manual was used in several cases to help select
     * a keycode reflecting the intended usage.
     *
     * RC5 codes are 14 bits, with two start bits (0x3 prefix)
     * and a toggle bit (masked out below).
     */
    { KE_KEY, 0x300c, { KEY_POWER } },  /* NOTE: docs omit this */
    { KE_KEY, 0x3000, { KEY_NUMERIC_0 } },
    { KE_KEY, 0x3001, { KEY_NUMERIC_1 } },
    { KE_KEY, 0x3002, { KEY_NUMERIC_2 } },
    { KE_KEY, 0x3003, { KEY_NUMERIC_3 } },
    { KE_KEY, 0x3004, { KEY_NUMERIC_4 } },
    { KE_KEY, 0x3005, { KEY_NUMERIC_5 } },
    { KE_KEY, 0x3006, { KEY_NUMERIC_6 } },
    { KE_KEY, 0x3007, { KEY_NUMERIC_7 } },
    { KE_KEY, 0x3008, { KEY_NUMERIC_8 } },
    { KE_KEY, 0x3009, { KEY_NUMERIC_9 } },
    { KE_KEY, 0x3022, { KEY_ENTER } },
    { KE_KEY, 0x30ec, { KEY_MODE } },   /* "tv/vcr/..." */
    { KE_KEY, 0x300f, { KEY_SELECT } }, /* "info" */
    { KE_KEY, 0x3020, { KEY_CHANNELUP } },  /* "up" */
    { KE_KEY, 0x302e, { KEY_MENU } },   /* "in/out" */
    { KE_KEY, 0x3011, { KEY_VOLUMEDOWN } }, /* "left" */
    { KE_KEY, 0x300d, { KEY_MUTE } },   /* "ok" */
    { KE_KEY, 0x3010, { KEY_VOLUMEUP } },   /* "right" */
    { KE_KEY, 0x301e, { KEY_SUBTITLE } },   /* "cc" */
    { KE_KEY, 0x3021, { KEY_CHANNELDOWN } },/* "down" */
    { KE_KEY, 0x3022, { KEY_PREVIOUS } },
    { KE_KEY, 0x3026, { KEY_SLEEP } },
    { KE_KEY, 0x3172, { KEY_REWIND } }, /* NOTE: docs wrongly say 0x30ca */
    { KE_KEY, 0x3175, { KEY_PLAY } },
    { KE_KEY, 0x3174, { KEY_FASTFORWARD } },
    { KE_KEY, 0x3177, { KEY_RECORD } },
    { KE_KEY, 0x3176, { KEY_STOP } },
    { KE_KEY, 0x3169, { KEY_PAUSE } },
};

/*
 * Because we communicate with the MSP430 using I2C, and all I2C calls
 * in Linux sleep, we use a threaded IRQ handler.  The IRQ itself is
 * active low, but we go through the GPIO controller so we can trigger
 * on falling edges and not worry about enabling/disabling the IRQ in
 * the keypress handling path.
 */
static irqreturn_t dm355evm_keys_irq(int irq, void *_keys)
{
    static u16 last_event;
    struct dm355evm_keys *keys = _keys;
    const struct key_entry *ke;
    unsigned int keycode;
    int status;
    u16 event;

    /* For simplicity we ignore INPUT_COUNT and just read
     * events until we get the "queue empty" indicator.
     * Reading INPUT_LOW decrements the count.
     */
    for (;;) {
        status = dm355evm_msp_read(DM355EVM_MSP_INPUT_HIGH);
        if (status < 0) {
            dev_dbg(keys->dev, "input high err %d\n",
                    status);
            break;
        }
        event = status << 8;

        status = dm355evm_msp_read(DM355EVM_MSP_INPUT_LOW);
        if (status < 0) {
            dev_dbg(keys->dev, "input low err %d\n",
                    status);
            break;
        }
        event |= status;
        if (event == 0xdead)
            break;

        /* Press and release a button:  two events, same code.
         * Press and hold (autorepeat), then release: N events
         * (N > 2), same code.  For RC5 buttons the toggle bits
         * distinguish (for example) "1-autorepeat" from "1 1";
         * but PCB buttons don't support that bit.
         *
         * So we must synthesize release events.  We do that by
         * mapping events to a press/release event pair; then
         * to avoid adding extra events, skip the second event
         * of each pair.
         */
        if (event == last_event) {
            last_event = 0;
            continue;
        }
        last_event = event;

        /* ignore the RC5 toggle bit */
        event &= ~0x0800;

        /* find the key, or report it as unknown */
        ke = sparse_keymap_entry_from_scancode(keys->input, event);
        keycode = ke ? ke->keycode : KEY_UNKNOWN;
        dev_dbg(keys->dev,
            "input event 0x%04x--> keycode %d\n",
            event, keycode);

        /* report press + release */
        input_report_key(keys->input, keycode, 1);
        input_sync(keys->input);
        input_report_key(keys->input, keycode, 0);
        input_sync(keys->input);
    }

    return IRQ_HANDLED;
}

/*----------------------------------------------------------------------*/

static int __devinit dm355evm_keys_probe(struct platform_device *pdev)
{
    struct dm355evm_keys    *keys;
    struct input_dev    *input;
    int         status;

    /* allocate instance struct and input dev */
    keys = kzalloc(sizeof *keys, GFP_KERNEL);
    input = input_allocate_device();
    if (!keys || !input) {
        status = -ENOMEM;
        goto fail1;
    }

    keys->dev = &pdev->dev;
    keys->input = input;

    /* set up "threaded IRQ handler" */
    status = platform_get_irq(pdev, 0);
    if (status < 0)
        goto fail1;
    keys->irq = status;

    input_set_drvdata(input, keys);

    input->name = "DM355 EVM Controls";
    input->phys = "dm355evm/input0";
    input->dev.parent = &pdev->dev;

    input->id.bustype = BUS_I2C;
    input->id.product = 0x0355;
    input->id.version = dm355evm_msp_read(DM355EVM_MSP_FIRMREV);

    status = sparse_keymap_setup(input, dm355evm_keys, NULL);
    if (status)
        goto fail1;

    /* REVISIT:  flush the event queue? */

    status = request_threaded_irq(keys->irq, NULL, dm355evm_keys_irq,
                      IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                      dev_name(&pdev->dev), keys);
    if (status < 0)
        goto fail2;

    /* register */
    status = input_register_device(input);
    if (status < 0)
        goto fail3;

    platform_set_drvdata(pdev, keys);

    return 0;

fail3:
    free_irq(keys->irq, keys);
fail2:
    sparse_keymap_free(input);
fail1:
    input_free_device(input);
    kfree(keys);
    dev_err(&pdev->dev, "can't register, err %d\n", status);

    return status;
}

static int __devexit dm355evm_keys_remove(struct platform_device *pdev)
{
    struct dm355evm_keys    *keys = platform_get_drvdata(pdev);

    free_irq(keys->irq, keys);
    sparse_keymap_free(keys->input);
    input_unregister_device(keys->input);
    kfree(keys);

    return 0;
}

/* REVISIT:  add suspend/resume when DaVinci supports it.  The IRQ should
 * be able to wake up the system.  When device_may_wakeup(&pdev->dev), call
 * enable_irq_wake() on suspend, and disable_irq_wake() on resume.
 */

/*
 * I2C is used to talk to the MSP430, but this platform device is
 * exposed by an MFD driver that manages I2C communications.
 */
static struct platform_driver dm355evm_keys_driver = {
    .probe      = dm355evm_keys_probe,
    .remove     = __devexit_p(dm355evm_keys_remove),
    .driver     = {
        .owner  = THIS_MODULE,
        .name   = "dm355evm_keys",
    },
};
module_platform_driver(dm355evm_keys_driver);

MODULE_LICENSE("GPL");