mirror of https://gitee.com/openkylin/linux.git
200 lines
4.7 KiB
C
200 lines
4.7 KiB
C
/* ir-jvc-decoder.c - handle JVC IR Pulse/Space protocol
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*
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* Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/bitrev.h>
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#include <linux/module.h>
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#include "rc-core-priv.h"
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#define JVC_NBITS 16 /* dev(8) + func(8) */
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#define JVC_UNIT 525000 /* ns */
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#define JVC_HEADER_PULSE (16 * JVC_UNIT) /* lack of header -> repeat */
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#define JVC_HEADER_SPACE (8 * JVC_UNIT)
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#define JVC_BIT_PULSE (1 * JVC_UNIT)
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#define JVC_BIT_0_SPACE (1 * JVC_UNIT)
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#define JVC_BIT_1_SPACE (3 * JVC_UNIT)
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#define JVC_TRAILER_PULSE (1 * JVC_UNIT)
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#define JVC_TRAILER_SPACE (35 * JVC_UNIT)
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enum jvc_state {
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STATE_INACTIVE,
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STATE_HEADER_SPACE,
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STATE_BIT_PULSE,
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STATE_BIT_SPACE,
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STATE_TRAILER_PULSE,
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STATE_TRAILER_SPACE,
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STATE_CHECK_REPEAT,
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};
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/**
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* ir_jvc_decode() - Decode one JVC pulse or space
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* @dev: the struct rc_dev descriptor of the device
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* @duration: the struct ir_raw_event descriptor of the pulse/space
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*
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* This function returns -EINVAL if the pulse violates the state machine
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*/
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static int ir_jvc_decode(struct rc_dev *dev, struct ir_raw_event ev)
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{
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struct jvc_dec *data = &dev->raw->jvc;
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if (!(dev->enabled_protocols & RC_BIT_JVC))
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return 0;
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if (!is_timing_event(ev)) {
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if (ev.reset)
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data->state = STATE_INACTIVE;
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return 0;
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}
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if (!geq_margin(ev.duration, JVC_UNIT, JVC_UNIT / 2))
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goto out;
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IR_dprintk(2, "JVC decode started at state %d (%uus %s)\n",
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data->state, TO_US(ev.duration), TO_STR(ev.pulse));
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again:
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switch (data->state) {
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case STATE_INACTIVE:
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if (!ev.pulse)
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break;
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if (!eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2))
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break;
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data->count = 0;
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data->first = true;
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data->toggle = !data->toggle;
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data->state = STATE_HEADER_SPACE;
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return 0;
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case STATE_HEADER_SPACE:
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if (ev.pulse)
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break;
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if (!eq_margin(ev.duration, JVC_HEADER_SPACE, JVC_UNIT / 2))
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break;
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data->state = STATE_BIT_PULSE;
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return 0;
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case STATE_BIT_PULSE:
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if (!ev.pulse)
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break;
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if (!eq_margin(ev.duration, JVC_BIT_PULSE, JVC_UNIT / 2))
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break;
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data->state = STATE_BIT_SPACE;
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return 0;
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case STATE_BIT_SPACE:
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if (ev.pulse)
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break;
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data->bits <<= 1;
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if (eq_margin(ev.duration, JVC_BIT_1_SPACE, JVC_UNIT / 2)) {
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data->bits |= 1;
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decrease_duration(&ev, JVC_BIT_1_SPACE);
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} else if (eq_margin(ev.duration, JVC_BIT_0_SPACE, JVC_UNIT / 2))
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decrease_duration(&ev, JVC_BIT_0_SPACE);
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else
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break;
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data->count++;
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if (data->count == JVC_NBITS)
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data->state = STATE_TRAILER_PULSE;
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else
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data->state = STATE_BIT_PULSE;
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return 0;
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case STATE_TRAILER_PULSE:
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if (!ev.pulse)
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break;
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if (!eq_margin(ev.duration, JVC_TRAILER_PULSE, JVC_UNIT / 2))
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break;
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data->state = STATE_TRAILER_SPACE;
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return 0;
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case STATE_TRAILER_SPACE:
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if (ev.pulse)
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break;
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if (!geq_margin(ev.duration, JVC_TRAILER_SPACE, JVC_UNIT / 2))
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break;
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if (data->first) {
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u32 scancode;
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scancode = (bitrev8((data->bits >> 8) & 0xff) << 8) |
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(bitrev8((data->bits >> 0) & 0xff) << 0);
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IR_dprintk(1, "JVC scancode 0x%04x\n", scancode);
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rc_keydown(dev, scancode, data->toggle);
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data->first = false;
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data->old_bits = data->bits;
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} else if (data->bits == data->old_bits) {
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IR_dprintk(1, "JVC repeat\n");
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rc_repeat(dev);
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} else {
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IR_dprintk(1, "JVC invalid repeat msg\n");
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break;
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}
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data->count = 0;
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data->state = STATE_CHECK_REPEAT;
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return 0;
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case STATE_CHECK_REPEAT:
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if (!ev.pulse)
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break;
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if (eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2))
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data->state = STATE_INACTIVE;
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else
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data->state = STATE_BIT_PULSE;
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goto again;
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}
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out:
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IR_dprintk(1, "JVC decode failed at state %d (%uus %s)\n",
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data->state, TO_US(ev.duration), TO_STR(ev.pulse));
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data->state = STATE_INACTIVE;
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return -EINVAL;
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}
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static struct ir_raw_handler jvc_handler = {
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.protocols = RC_BIT_JVC,
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.decode = ir_jvc_decode,
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};
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static int __init ir_jvc_decode_init(void)
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{
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ir_raw_handler_register(&jvc_handler);
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printk(KERN_INFO "IR JVC protocol handler initialized\n");
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return 0;
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}
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static void __exit ir_jvc_decode_exit(void)
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{
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ir_raw_handler_unregister(&jvc_handler);
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}
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module_init(ir_jvc_decode_init);
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module_exit(ir_jvc_decode_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
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MODULE_DESCRIPTION("JVC IR protocol decoder");
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