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407 lines
9.5 KiB
407 lines
9.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol |
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* |
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* Copyright (C) 2010 by David Härdeman <[email protected]> |
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*/ |
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#include "rc-core-priv.h" |
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#include <linux/module.h> |
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/* |
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* This decoder currently supports: |
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* RC6-0-16 (standard toggle bit in header) |
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* RC6-6A-20 (no toggle bit) |
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* RC6-6A-24 (no toggle bit) |
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* RC6-6A-32 (MCE version with toggle bit in body) |
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*/ |
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#define RC6_UNIT 444 /* microseconds */ |
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#define RC6_HEADER_NBITS 4 /* not including toggle bit */ |
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#define RC6_0_NBITS 16 |
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#define RC6_6A_32_NBITS 32 |
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#define RC6_6A_NBITS 128 /* Variable 8..128 */ |
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#define RC6_PREFIX_PULSE (6 * RC6_UNIT) |
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#define RC6_PREFIX_SPACE (2 * RC6_UNIT) |
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#define RC6_BIT_START (1 * RC6_UNIT) |
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#define RC6_BIT_END (1 * RC6_UNIT) |
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#define RC6_TOGGLE_START (2 * RC6_UNIT) |
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#define RC6_TOGGLE_END (2 * RC6_UNIT) |
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#define RC6_SUFFIX_SPACE (6 * RC6_UNIT) |
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#define RC6_MODE_MASK 0x07 /* for the header bits */ |
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#define RC6_STARTBIT_MASK 0x08 /* for the header bits */ |
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#define RC6_6A_MCE_TOGGLE_MASK 0x8000 /* for the body bits */ |
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#define RC6_6A_LCC_MASK 0xffff0000 /* RC6-6A-32 long customer code mask */ |
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#define RC6_6A_MCE_CC 0x800f0000 /* MCE customer code */ |
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#define RC6_6A_ZOTAC_CC 0x80340000 /* Zotac customer code */ |
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#define RC6_6A_KATHREIN_CC 0x80460000 /* Kathrein RCU-676 customer code */ |
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#ifndef CHAR_BIT |
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#define CHAR_BIT 8 /* Normally in <limits.h> */ |
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#endif |
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enum rc6_mode { |
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RC6_MODE_0, |
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RC6_MODE_6A, |
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RC6_MODE_UNKNOWN, |
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}; |
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enum rc6_state { |
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STATE_INACTIVE, |
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STATE_PREFIX_SPACE, |
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STATE_HEADER_BIT_START, |
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STATE_HEADER_BIT_END, |
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STATE_TOGGLE_START, |
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STATE_TOGGLE_END, |
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STATE_BODY_BIT_START, |
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STATE_BODY_BIT_END, |
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STATE_FINISHED, |
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}; |
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static enum rc6_mode rc6_mode(struct rc6_dec *data) |
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{ |
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switch (data->header & RC6_MODE_MASK) { |
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case 0: |
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return RC6_MODE_0; |
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case 6: |
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if (!data->toggle) |
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return RC6_MODE_6A; |
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fallthrough; |
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default: |
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return RC6_MODE_UNKNOWN; |
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} |
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} |
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/** |
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* ir_rc6_decode() - Decode one RC6 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_rc6_decode(struct rc_dev *dev, struct ir_raw_event ev) |
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{ |
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struct rc6_dec *data = &dev->raw->rc6; |
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u32 scancode; |
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u8 toggle; |
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enum rc_proto protocol; |
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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, RC6_UNIT, RC6_UNIT / 2)) |
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goto out; |
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again: |
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dev_dbg(&dev->dev, "RC6 decode started at state %i (%uus %s)\n", |
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data->state, ev.duration, TO_STR(ev.pulse)); |
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if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2)) |
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return 0; |
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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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/* Note: larger margin on first pulse since each RC6_UNIT |
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is quite short and some hardware takes some time to |
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adjust to the signal */ |
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if (!eq_margin(ev.duration, RC6_PREFIX_PULSE, RC6_UNIT)) |
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break; |
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data->state = STATE_PREFIX_SPACE; |
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data->count = 0; |
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return 0; |
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case STATE_PREFIX_SPACE: |
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if (ev.pulse) |
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break; |
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if (!eq_margin(ev.duration, RC6_PREFIX_SPACE, RC6_UNIT / 2)) |
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break; |
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data->state = STATE_HEADER_BIT_START; |
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data->header = 0; |
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return 0; |
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case STATE_HEADER_BIT_START: |
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if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) |
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break; |
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data->header <<= 1; |
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if (ev.pulse) |
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data->header |= 1; |
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data->count++; |
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data->state = STATE_HEADER_BIT_END; |
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return 0; |
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case STATE_HEADER_BIT_END: |
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if (data->count == RC6_HEADER_NBITS) |
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data->state = STATE_TOGGLE_START; |
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else |
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data->state = STATE_HEADER_BIT_START; |
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decrease_duration(&ev, RC6_BIT_END); |
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goto again; |
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case STATE_TOGGLE_START: |
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if (!eq_margin(ev.duration, RC6_TOGGLE_START, RC6_UNIT / 2)) |
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break; |
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data->toggle = ev.pulse; |
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data->state = STATE_TOGGLE_END; |
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return 0; |
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case STATE_TOGGLE_END: |
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if (!(data->header & RC6_STARTBIT_MASK)) { |
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dev_dbg(&dev->dev, "RC6 invalid start bit\n"); |
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break; |
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} |
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data->state = STATE_BODY_BIT_START; |
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decrease_duration(&ev, RC6_TOGGLE_END); |
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data->count = 0; |
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data->body = 0; |
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switch (rc6_mode(data)) { |
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case RC6_MODE_0: |
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data->wanted_bits = RC6_0_NBITS; |
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break; |
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case RC6_MODE_6A: |
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data->wanted_bits = RC6_6A_NBITS; |
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break; |
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default: |
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dev_dbg(&dev->dev, "RC6 unknown mode\n"); |
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goto out; |
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} |
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goto again; |
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case STATE_BODY_BIT_START: |
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if (eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) { |
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/* Discard LSB's that won't fit in data->body */ |
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if (data->count++ < CHAR_BIT * sizeof data->body) { |
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data->body <<= 1; |
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if (ev.pulse) |
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data->body |= 1; |
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} |
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data->state = STATE_BODY_BIT_END; |
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return 0; |
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} else if (RC6_MODE_6A == rc6_mode(data) && !ev.pulse && |
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geq_margin(ev.duration, RC6_SUFFIX_SPACE, RC6_UNIT / 2)) { |
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data->state = STATE_FINISHED; |
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goto again; |
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} |
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break; |
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case STATE_BODY_BIT_END: |
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if (data->count == data->wanted_bits) |
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data->state = STATE_FINISHED; |
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else |
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data->state = STATE_BODY_BIT_START; |
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decrease_duration(&ev, RC6_BIT_END); |
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goto again; |
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case STATE_FINISHED: |
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if (ev.pulse) |
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break; |
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switch (rc6_mode(data)) { |
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case RC6_MODE_0: |
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scancode = data->body; |
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toggle = data->toggle; |
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protocol = RC_PROTO_RC6_0; |
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dev_dbg(&dev->dev, "RC6(0) scancode 0x%04x (toggle: %u)\n", |
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scancode, toggle); |
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break; |
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case RC6_MODE_6A: |
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if (data->count > CHAR_BIT * sizeof data->body) { |
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dev_dbg(&dev->dev, "RC6 too many (%u) data bits\n", |
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data->count); |
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goto out; |
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} |
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scancode = data->body; |
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switch (data->count) { |
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case 20: |
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protocol = RC_PROTO_RC6_6A_20; |
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toggle = 0; |
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break; |
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case 24: |
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protocol = RC_PROTO_RC6_6A_24; |
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toggle = 0; |
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break; |
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case 32: |
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switch (scancode & RC6_6A_LCC_MASK) { |
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case RC6_6A_MCE_CC: |
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case RC6_6A_KATHREIN_CC: |
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case RC6_6A_ZOTAC_CC: |
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protocol = RC_PROTO_RC6_MCE; |
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toggle = !!(scancode & RC6_6A_MCE_TOGGLE_MASK); |
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scancode &= ~RC6_6A_MCE_TOGGLE_MASK; |
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break; |
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default: |
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protocol = RC_PROTO_RC6_6A_32; |
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toggle = 0; |
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break; |
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} |
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break; |
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default: |
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dev_dbg(&dev->dev, "RC6(6A) unsupported length\n"); |
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goto out; |
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} |
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dev_dbg(&dev->dev, "RC6(6A) proto 0x%04x, scancode 0x%08x (toggle: %u)\n", |
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protocol, scancode, toggle); |
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break; |
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default: |
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dev_dbg(&dev->dev, "RC6 unknown mode\n"); |
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goto out; |
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} |
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rc_keydown(dev, protocol, scancode, toggle); |
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data->state = STATE_INACTIVE; |
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return 0; |
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} |
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out: |
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dev_dbg(&dev->dev, "RC6 decode failed at state %i (%uus %s)\n", |
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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_manchester ir_rc6_timings[4] = { |
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{ |
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.leader_pulse = RC6_PREFIX_PULSE, |
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.leader_space = RC6_PREFIX_SPACE, |
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.clock = RC6_UNIT, |
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.invert = 1, |
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}, |
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{ |
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.clock = RC6_UNIT * 2, |
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.invert = 1, |
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}, |
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{ |
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.clock = RC6_UNIT, |
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.invert = 1, |
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.trailer_space = RC6_SUFFIX_SPACE, |
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}, |
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}; |
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/** |
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* ir_rc6_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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* -EINVAL if the scancode is ambiguous or invalid. |
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*/ |
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static int ir_rc6_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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int ret; |
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struct ir_raw_event *e = events; |
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if (protocol == RC_PROTO_RC6_0) { |
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/* Modulate the header (Start Bit & Mode-0) */ |
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ret = ir_raw_gen_manchester(&e, max - (e - events), |
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&ir_rc6_timings[0], |
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RC6_HEADER_NBITS, (1 << 3)); |
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if (ret < 0) |
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return ret; |
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/* Modulate Trailer Bit */ |
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ret = ir_raw_gen_manchester(&e, max - (e - events), |
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&ir_rc6_timings[1], 1, 0); |
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if (ret < 0) |
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return ret; |
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/* Modulate rest of the data */ |
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ret = ir_raw_gen_manchester(&e, max - (e - events), |
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&ir_rc6_timings[2], RC6_0_NBITS, |
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scancode); |
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if (ret < 0) |
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return ret; |
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} else { |
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int bits; |
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switch (protocol) { |
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case RC_PROTO_RC6_MCE: |
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case RC_PROTO_RC6_6A_32: |
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bits = 32; |
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break; |
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case RC_PROTO_RC6_6A_24: |
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bits = 24; |
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break; |
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case RC_PROTO_RC6_6A_20: |
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bits = 20; |
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break; |
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default: |
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return -EINVAL; |
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} |
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/* Modulate the header (Start Bit & Header-version 6 */ |
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ret = ir_raw_gen_manchester(&e, max - (e - events), |
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&ir_rc6_timings[0], |
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RC6_HEADER_NBITS, (1 << 3 | 6)); |
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if (ret < 0) |
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return ret; |
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/* Modulate Trailer Bit */ |
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ret = ir_raw_gen_manchester(&e, max - (e - events), |
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&ir_rc6_timings[1], 1, 0); |
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if (ret < 0) |
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return ret; |
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/* Modulate rest of the data */ |
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ret = ir_raw_gen_manchester(&e, max - (e - events), |
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&ir_rc6_timings[2], |
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bits, |
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scancode); |
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if (ret < 0) |
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return ret; |
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} |
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return e - events; |
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} |
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static struct ir_raw_handler rc6_handler = { |
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.protocols = RC_PROTO_BIT_RC6_0 | RC_PROTO_BIT_RC6_6A_20 | |
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RC_PROTO_BIT_RC6_6A_24 | RC_PROTO_BIT_RC6_6A_32 | |
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RC_PROTO_BIT_RC6_MCE, |
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.decode = ir_rc6_decode, |
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.encode = ir_rc6_encode, |
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.carrier = 36000, |
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.min_timeout = RC6_SUFFIX_SPACE, |
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}; |
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static int __init ir_rc6_decode_init(void) |
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{ |
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ir_raw_handler_register(&rc6_handler); |
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printk(KERN_INFO "IR RC6 protocol handler initialized\n"); |
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return 0; |
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} |
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static void __exit ir_rc6_decode_exit(void) |
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{ |
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ir_raw_handler_unregister(&rc6_handler); |
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} |
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module_init(ir_rc6_decode_init); |
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module_exit(ir_rc6_decode_exit); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("David Härdeman <[email protected]>"); |
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MODULE_DESCRIPTION("RC6 IR protocol decoder");
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