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242 lines
5.8 KiB
242 lines
5.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* 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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#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 40 /* us */ |
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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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* @ev: 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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dev_dbg(&dev->dev, "Sharp decode started at state %d (%uus %s)\n", |
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data->state, 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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dev_dbg(&dev->dev, |
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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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dev_dbg(&dev->dev, "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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dev_dbg(&dev->dev, "Sharp decode failed at count %d state %d (%uus %s)\n", |
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data->count, data->state, 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 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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.carrier = 38000, |
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.min_timeout = SHARP_ECHO_SPACE + SHARP_ECHO_SPACE / 4, |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("Sharp IR protocol decoder");
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