linux-imx

// SPDX-License-Identifier: GPL-2.0-only

/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol

 *

 * Copyright (C) 2013-2014 Imagination Technologies Ltd.

 *

 * Based on NEC decoder:

 * Copyright (C) 2010 by Mauro Carvalho Chehab

 */

​

#include <linux/bitrev.h>

#include <linux/module.h>

#include "rc-core-priv.h"

​

#define SHARP_NBITS     15

#define SHARP_UNIT      40000  /* ns */

#define SHARP_BIT_PULSE     (8    * SHARP_UNIT) /* 320us */

#define SHARP_BIT_0_PERIOD  (25   * SHARP_UNIT) /* 1ms (680us space) */

#define SHARP_BIT_1_PERIOD  (50   * SHARP_UNIT) /* 2ms (1680ms space) */

#define SHARP_ECHO_SPACE    (1000 * SHARP_UNIT) /* 40 ms */

#define SHARP_TRAILER_SPACE (125  * SHARP_UNIT) /* 5 ms (even longer) */

​

enum sharp_state {

    STATE_INACTIVE,

    STATE_BIT_PULSE,

    STATE_BIT_SPACE,

    STATE_TRAILER_PULSE,

    STATE_ECHO_SPACE,

    STATE_TRAILER_SPACE,

};

​

/**

 * ir_sharp_decode() - Decode one Sharp pulse or space

 * @dev:    the struct rc_dev descriptor of the device

 * @ev:     the struct ir_raw_event descriptor of the pulse/space

 *

 * This function returns -EINVAL if the pulse violates the state machine

 */

static int ir_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)

{

    struct sharp_dec *data = &dev->raw->sharp;

    u32 msg, echo, address, command, scancode;

​

    if (!is_timing_event(ev)) {

        if (ev.reset)

            data->state = STATE_INACTIVE;

        return 0;

    }

​

    dev_dbg(&dev->dev, "Sharp decode started at state %d (%uus %s)\n",

        data->state, TO_US(ev.duration), TO_STR(ev.pulse));

​

    switch (data->state) {

​

    case STATE_INACTIVE:

        if (!ev.pulse)

            break;

​

        if (!eq_margin(ev.duration, SHARP_BIT_PULSE,

                   SHARP_BIT_PULSE / 2))

            break;

​

        data->count = 0;

        data->pulse_len = ev.duration;

        data->state = STATE_BIT_SPACE;

        return 0;

​

    case STATE_BIT_PULSE:

        if (!ev.pulse)

            break;

​

        if (!eq_margin(ev.duration, SHARP_BIT_PULSE,

                   SHARP_BIT_PULSE / 2))

            break;

​

        data->pulse_len = ev.duration;

        data->state = STATE_BIT_SPACE;

        return 0;

​

    case STATE_BIT_SPACE:

        if (ev.pulse)

            break;

​

        data->bits <<= 1;

        if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,

                  SHARP_BIT_PULSE * 2))

            data->bits |= 1;

        else if (!eq_margin(data->pulse_len + ev.duration,

                    SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))

            break;

        data->count++;

​

        if (data->count == SHARP_NBITS ||