ir-sanyo-decoder.c

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/* ir-sanyo-decoder.c - handle SANYO IR Pulse/Space protocol
 *
 * Copyright (C) 2011 by Mauro Carvalho Chehab <[email protected]>
 *
 * 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 version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 * This protocol uses the NEC protocol timings. However, data is formatted as:
 *  13 bits Custom Code
 *  13 bits NOT(Custom Code)
 *  8 bits Key data
 *  8 bits NOT(Key data)
 *
 * According with LIRC, this protocol is used on Sanyo, Aiwa and Chinon
 * Information for this protocol is available at the Sanyo LC7461 datasheet.
 */

#include <linux/module.h>
#include <linux/bitrev.h>
#include "rc-core-priv.h"

#define SANYO_NBITS     (13+13+8+8)
#define SANYO_UNIT      562500  /* ns */
#define SANYO_HEADER_PULSE  (16  * SANYO_UNIT)
#define SANYO_HEADER_SPACE  (8   * SANYO_UNIT)
#define SANYO_BIT_PULSE     (1   * SANYO_UNIT)
#define SANYO_BIT_0_SPACE   (1   * SANYO_UNIT)
#define SANYO_BIT_1_SPACE   (3   * SANYO_UNIT)
#define SANYO_REPEAT_SPACE  (150 * SANYO_UNIT)
#define SANYO_TRAILER_PULSE (1   * SANYO_UNIT)
#define SANYO_TRAILER_SPACE (10  * SANYO_UNIT)  /* in fact, 42 */

enum sanyo_state {
    STATE_INACTIVE,
    STATE_HEADER_SPACE,
    STATE_BIT_PULSE,
    STATE_BIT_SPACE,
    STATE_TRAILER_PULSE,
    STATE_TRAILER_SPACE,
};

static int ir_sanyo_decode(struct rc_dev *dev, struct ir_raw_event ev)
{
    struct sanyo_dec *data = &dev->raw->sanyo;
    u32 scancode;
    u8 address, command, not_command;

    if (!(dev->raw->enabled_protocols & RC_TYPE_SANYO))
        return 0;

    if (!is_timing_event(ev)) {
        if (ev.reset) {
            IR_dprintk(1, "SANYO event reset received. reset to state 0\n");
            data->state = STATE_INACTIVE;
        }
        return 0;
    }

    IR_dprintk(2, "SANYO 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, SANYO_HEADER_PULSE, SANYO_UNIT / 2)) {
            data->count = 0;
            data->state = STATE_HEADER_SPACE;
            return 0;
        }
        break;


    case STATE_HEADER_SPACE:
        if (ev.pulse)
            break;

        if (eq_margin(ev.duration, SANYO_HEADER_SPACE, SANYO_UNIT / 2)) {
            data->state = STATE_BIT_PULSE;
            return 0;
        }

        break;

    case STATE_BIT_PULSE:
        if (!ev.pulse)
            break;

        if (!eq_margin(ev.duration, SANYO_BIT_PULSE, SANYO_UNIT / 2))
            break;

        data->state = STATE_BIT_SPACE;
        return 0;

    case STATE_BIT_SPACE:
        if (ev.pulse)
            break;

        if (!data->count && geq_margin(ev.duration, SANYO_REPEAT_SPACE, SANYO_UNIT / 2)) {
            if (!dev->keypressed) {
                IR_dprintk(1, "SANYO discarding last key repeat: event after key up\n");
            } else {
                rc_repeat(dev);
                IR_dprintk(1, "SANYO repeat last key\n");
                data->state = STATE_INACTIVE;
            }
            return 0;
        }

        data->bits <<= 1;
        if (eq_margin(ev.duration, SANYO_BIT_1_SPACE, SANYO_UNIT / 2))
            data->bits |= 1;
        else if (!eq_margin(ev.duration, SANYO_BIT_0_SPACE, SANYO_UNIT / 2))
            break;
        data->count++;

        if (data->count == SANYO_NBITS)
            data->state = STATE_TRAILER_PULSE;
        else
            data->state = STATE_BIT_PULSE;

        return 0;

    case STATE_TRAILER_PULSE:
        if (!ev.pulse)
            break;

        if (!eq_margin(ev.duration, SANYO_TRAILER_PULSE, SANYO_UNIT / 2))
            break;

        data->state = STATE_TRAILER_SPACE;
        return 0;

    case STATE_TRAILER_SPACE:
        if (ev.pulse)
            break;

        if (!geq_margin(ev.duration, SANYO_TRAILER_SPACE, SANYO_UNIT / 2))
            break;

        address     = bitrev16((data->bits >> 29) & 0x1fff) >> 3;
        /* not_address = bitrev16((data->bits >> 16) & 0x1fff) >> 3; */
        command     = bitrev8((data->bits >>  8) & 0xff);
        not_command = bitrev8((data->bits >>  0) & 0xff);

        if ((command ^ not_command) != 0xff) {
            IR_dprintk(1, "SANYO checksum error: received 0x%08Lx\n",
                   data->bits);
            data->state = STATE_INACTIVE;
            return 0;
        }

        scancode = address << 8 | command;
        IR_dprintk(1, "SANYO scancode: 0x%06x\n", scancode);
        rc_keydown(dev, scancode, 0);
        data->state = STATE_INACTIVE;
        return 0;
    }

    IR_dprintk(1, "SANYO decode failed at count %d state %d (%uus %s)\n",
           data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
    data->state = STATE_INACTIVE;
    return -EINVAL;
}

static struct ir_raw_handler sanyo_handler = {
    .protocols  = RC_TYPE_SANYO,
    .decode     = ir_sanyo_decode,
};

static int __init ir_sanyo_decode_init(void)
{
    ir_raw_handler_register(&sanyo_handler);

    printk(KERN_INFO "IR SANYO protocol handler initialized\n");
    return 0;
}

static void __exit ir_sanyo_decode_exit(void)
{
    ir_raw_handler_unregister(&sanyo_handler);
}

module_init(ir_sanyo_decode_init);
module_exit(ir_sanyo_decode_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mauro Carvalho Chehab <[email protected]>");
MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
MODULE_DESCRIPTION("SANYO IR protocol decoder");