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249 lines
6.1 KiB
249 lines
6.1 KiB
/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol
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*
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* Copyright (C) 2013-2014 Imagination Technologies Ltd.
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*
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* Based on NEC decoder:
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* Copyright (C) 2010 by Mauro Carvalho Chehab
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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 SHARP_NBITS 15
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#define SHARP_UNIT 40000 /* ns */
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#define SHARP_BIT_PULSE (8 * SHARP_UNIT) /* 320us */
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#define SHARP_BIT_0_PERIOD (25 * SHARP_UNIT) /* 1ms (680us space) */
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#define SHARP_BIT_1_PERIOD (50 * SHARP_UNIT) /* 2ms (1680ms space) */
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#define SHARP_ECHO_SPACE (1000 * SHARP_UNIT) /* 40 ms */
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#define SHARP_TRAILER_SPACE (125 * SHARP_UNIT) /* 5 ms (even longer) */
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enum sharp_state {
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STATE_INACTIVE,
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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_ECHO_SPACE,
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STATE_TRAILER_SPACE,
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};
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/**
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* ir_sharp_decode() - Decode one Sharp 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_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)
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{
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struct sharp_dec *data = &dev->raw->sharp;
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u32 msg, echo, address, command, scancode;
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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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IR_dprintk(2, "Sharp 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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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, SHARP_BIT_PULSE,
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SHARP_BIT_PULSE / 2))
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break;
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data->count = 0;
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data->pulse_len = ev.duration;
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data->state = STATE_BIT_SPACE;
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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, SHARP_BIT_PULSE,
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SHARP_BIT_PULSE / 2))
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break;
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data->pulse_len = ev.duration;
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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(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,
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SHARP_BIT_PULSE * 2))
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data->bits |= 1;
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else if (!eq_margin(data->pulse_len + ev.duration,
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SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))
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break;
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data->count++;
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if (data->count == SHARP_NBITS ||
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data->count == SHARP_NBITS * 2)
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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, SHARP_BIT_PULSE,
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SHARP_BIT_PULSE / 2))
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break;
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if (data->count == SHARP_NBITS) {
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/* exp,chk bits should be 1,0 */
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if ((data->bits & 0x3) != 0x2 &&
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/* DENON variant, both chk bits 0 */
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(data->bits & 0x3) != 0x0)
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break;
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data->state = STATE_ECHO_SPACE;
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} else {
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data->state = STATE_TRAILER_SPACE;
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}
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return 0;
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case STATE_ECHO_SPACE:
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if (ev.pulse)
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break;
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if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,
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SHARP_ECHO_SPACE / 4))
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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_TRAILER_SPACE:
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if (ev.pulse)
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break;
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if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,
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SHARP_BIT_PULSE / 2))
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break;
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/* Validate - command, ext, chk should be inverted in 2nd */
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msg = (data->bits >> 15) & 0x7fff;
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echo = data->bits & 0x7fff;
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if ((msg ^ echo) != 0x3ff) {
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IR_dprintk(1,
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"Sharp checksum error: received 0x%04x, 0x%04x\n",
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msg, echo);
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break;
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}
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address = bitrev8((msg >> 7) & 0xf8);
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command = bitrev8((msg >> 2) & 0xff);
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scancode = address << 8 | command;
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IR_dprintk(1, "Sharp scancode 0x%04x\n", scancode);
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rc_keydown(dev, RC_PROTO_SHARP, scancode, 0);
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data->state = STATE_INACTIVE;
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return 0;
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}
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IR_dprintk(1, "Sharp decode failed at count %d state %d (%uus %s)\n",
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data->count, data->state, TO_US(ev.duration),
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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 const struct ir_raw_timings_pd ir_sharp_timings = {
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.header_pulse = 0,
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.header_space = 0,
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.bit_pulse = SHARP_BIT_PULSE,
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.bit_space[0] = SHARP_BIT_0_PERIOD,
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.bit_space[1] = SHARP_BIT_1_PERIOD,
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.trailer_pulse = SHARP_BIT_PULSE,
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.trailer_space = SHARP_ECHO_SPACE,
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.msb_first = 1,
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};
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/**
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* ir_sharp_encode() - Encode a scancode as a stream of raw events
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*
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* @protocol: protocol to encode
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* @scancode: scancode to encode
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* @events: array of raw ir events to write into
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* @max: maximum size of @events
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*
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* Returns: The number of events written.
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* -ENOBUFS if there isn't enough space in the array to fit the
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* encoding. In this case all @max events will have been written.
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*/
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static int ir_sharp_encode(enum rc_proto protocol, u32 scancode,
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struct ir_raw_event *events, unsigned int max)
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{
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struct ir_raw_event *e = events;
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int ret;
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u32 raw;
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raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |
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bitrev8(scancode);
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ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,
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(raw << 2) | 2);
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if (ret < 0)
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return ret;
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max -= ret;
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raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |
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bitrev8(~scancode);
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ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,
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(raw << 2) | 1);
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if (ret < 0)
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return ret;
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return e - events;
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}
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static struct ir_raw_handler sharp_handler = {
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.protocols = RC_PROTO_BIT_SHARP,
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.decode = ir_sharp_decode,
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.encode = ir_sharp_encode,
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};
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static int __init ir_sharp_decode_init(void)
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{
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ir_raw_handler_register(&sharp_handler);
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pr_info("IR Sharp protocol handler initialized\n");
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return 0;
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}
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static void __exit ir_sharp_decode_exit(void)
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{
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ir_raw_handler_unregister(&sharp_handler);
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}
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module_init(ir_sharp_decode_init);
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module_exit(ir_sharp_decode_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("James Hogan <jhogan@kernel.org>");
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MODULE_DESCRIPTION("Sharp IR protocol decoder");
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