linux-imx

// SPDX-License-Identifier: GPL-2.0

// ir-nec-decoder.c - handle NEC IR Pulse/Space protocol

//

// Copyright (C) 2010 by Mauro Carvalho Chehab

​

#include <linux/bitrev.h>

#include <linux/module.h>

#include "rc-core-priv.h"

​

#define NEC_NBITS       32

#define NEC_UNIT        562500  /* ns */

#define NEC_HEADER_PULSE    (16 * NEC_UNIT)

#define NECX_HEADER_PULSE   (8  * NEC_UNIT) /* Less common NEC variant */

#define NEC_HEADER_SPACE    (8  * NEC_UNIT)

#define NEC_REPEAT_SPACE    (4  * NEC_UNIT)

#define NEC_BIT_PULSE       (1  * NEC_UNIT)

#define NEC_BIT_0_SPACE     (1  * NEC_UNIT)

#define NEC_BIT_1_SPACE     (3  * NEC_UNIT)

#define NEC_TRAILER_PULSE   (1  * NEC_UNIT)

#define NEC_TRAILER_SPACE   (10 * NEC_UNIT) /* even longer in reality */

#define NECX_REPEAT_BITS    1

​

enum nec_state {

    STATE_INACTIVE,

    STATE_HEADER_SPACE,

    STATE_BIT_PULSE,

    STATE_BIT_SPACE,

    STATE_TRAILER_PULSE,

    STATE_TRAILER_SPACE,

};

​

/**

 * ir_nec_decode() - Decode one NEC 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_nec_decode(struct rc_dev *dev, struct ir_raw_event ev)

{

    struct nec_dec *data = &dev->raw->nec;

    u32 scancode;

    enum rc_proto rc_proto;

    u8 address, not_address, command, not_command;

​

    if (!is_timing_event(ev)) {

        if (ev.reset)

            data->state = STATE_INACTIVE;

        return 0;

    }

​

    dev_dbg(&dev->dev, "NEC 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, NEC_HEADER_PULSE, NEC_UNIT * 2)) {

            data->is_nec_x = false;

            data->necx_repeat = false;