| /* ir-rc6-decoder.c - A decoder for the RC6 IR protocol |
| * |
| * Copyright (C) 2010 by David Härdeman <david@hardeman.nu> |
| * |
| * 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. |
| */ |
| |
| #include "rc-core-priv.h" |
| #include <linux/module.h> |
| |
| /* |
| * This decoder currently supports: |
| * RC6-0-16 (standard toggle bit in header) |
| * RC6-6A-20 (no toggle bit) |
| * RC6-6A-24 (no toggle bit) |
| * RC6-6A-32 (MCE version with toggle bit in body) |
| */ |
| |
| #define RC6_UNIT 444444 /* nanosecs */ |
| #define RC6_HEADER_NBITS 4 /* not including toggle bit */ |
| #define RC6_0_NBITS 16 |
| #define RC6_6A_32_NBITS 32 |
| #define RC6_6A_NBITS 128 /* Variable 8..128 */ |
| #define RC6_PREFIX_PULSE (6 * RC6_UNIT) |
| #define RC6_PREFIX_SPACE (2 * RC6_UNIT) |
| #define RC6_BIT_START (1 * RC6_UNIT) |
| #define RC6_BIT_END (1 * RC6_UNIT) |
| #define RC6_TOGGLE_START (2 * RC6_UNIT) |
| #define RC6_TOGGLE_END (2 * RC6_UNIT) |
| #define RC6_SUFFIX_SPACE (6 * RC6_UNIT) |
| #define RC6_MODE_MASK 0x07 /* for the header bits */ |
| #define RC6_STARTBIT_MASK 0x08 /* for the header bits */ |
| #define RC6_6A_MCE_TOGGLE_MASK 0x8000 /* for the body bits */ |
| #define RC6_6A_LCC_MASK 0xffff0000 /* RC6-6A-32 long customer code mask */ |
| #define RC6_6A_MCE_CC 0x800f0000 /* MCE customer code */ |
| #ifndef CHAR_BIT |
| #define CHAR_BIT 8 /* Normally in <limits.h> */ |
| #endif |
| |
| enum rc6_mode { |
| RC6_MODE_0, |
| RC6_MODE_6A, |
| RC6_MODE_UNKNOWN, |
| }; |
| |
| enum rc6_state { |
| STATE_INACTIVE, |
| STATE_PREFIX_SPACE, |
| STATE_HEADER_BIT_START, |
| STATE_HEADER_BIT_END, |
| STATE_TOGGLE_START, |
| STATE_TOGGLE_END, |
| STATE_BODY_BIT_START, |
| STATE_BODY_BIT_END, |
| STATE_FINISHED, |
| }; |
| |
| static enum rc6_mode rc6_mode(struct rc6_dec *data) |
| { |
| switch (data->header & RC6_MODE_MASK) { |
| case 0: |
| return RC6_MODE_0; |
| case 6: |
| if (!data->toggle) |
| return RC6_MODE_6A; |
| /* fall through */ |
| default: |
| return RC6_MODE_UNKNOWN; |
| } |
| } |
| |
| /** |
| * ir_rc6_decode() - Decode one RC6 pulse or space |
| * @dev: the struct rc_dev descriptor of the device |
| * @ev: the struct ir_raw_event descriptor of the pulse/space |
| * |
| * This function returns -EINVAL if the pulse violates the state machine |
| */ |
| static int ir_rc6_decode(struct rc_dev *dev, struct ir_raw_event ev) |
| { |
| struct rc6_dec *data = &dev->raw->rc6; |
| u32 scancode; |
| u8 toggle; |
| enum rc_type protocol; |
| |
| if (!is_timing_event(ev)) { |
| if (ev.reset) |
| data->state = STATE_INACTIVE; |
| return 0; |
| } |
| |
| if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2)) |
| goto out; |
| |
| again: |
| IR_dprintk(2, "RC6 decode started at state %i (%uus %s)\n", |
| data->state, TO_US(ev.duration), TO_STR(ev.pulse)); |
| |
| if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2)) |
| return 0; |
| |
| switch (data->state) { |
| |
| case STATE_INACTIVE: |
| if (!ev.pulse) |
| break; |
| |
| /* Note: larger margin on first pulse since each RC6_UNIT |
| is quite short and some hardware takes some time to |
| adjust to the signal */ |
| if (!eq_margin(ev.duration, RC6_PREFIX_PULSE, RC6_UNIT)) |
| break; |
| |
| data->state = STATE_PREFIX_SPACE; |
| data->count = 0; |
| return 0; |
| |
| case STATE_PREFIX_SPACE: |
| if (ev.pulse) |
| break; |
| |
| if (!eq_margin(ev.duration, RC6_PREFIX_SPACE, RC6_UNIT / 2)) |
| break; |
| |
| data->state = STATE_HEADER_BIT_START; |
| data->header = 0; |
| return 0; |
| |
| case STATE_HEADER_BIT_START: |
| if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) |
| break; |
| |
| data->header <<= 1; |
| if (ev.pulse) |
| data->header |= 1; |
| data->count++; |
| data->state = STATE_HEADER_BIT_END; |
| return 0; |
| |
| case STATE_HEADER_BIT_END: |
| if (!is_transition(&ev, &dev->raw->prev_ev)) |
| break; |
| |
| if (data->count == RC6_HEADER_NBITS) |
| data->state = STATE_TOGGLE_START; |
| else |
| data->state = STATE_HEADER_BIT_START; |
| |
| decrease_duration(&ev, RC6_BIT_END); |
| goto again; |
| |
| case STATE_TOGGLE_START: |
| if (!eq_margin(ev.duration, RC6_TOGGLE_START, RC6_UNIT / 2)) |
| break; |
| |
| data->toggle = ev.pulse; |
| data->state = STATE_TOGGLE_END; |
| return 0; |
| |
| case STATE_TOGGLE_END: |
| if (!is_transition(&ev, &dev->raw->prev_ev) || |
| !geq_margin(ev.duration, RC6_TOGGLE_END, RC6_UNIT / 2)) |
| break; |
| |
| if (!(data->header & RC6_STARTBIT_MASK)) { |
| IR_dprintk(1, "RC6 invalid start bit\n"); |
| break; |
| } |
| |
| data->state = STATE_BODY_BIT_START; |
| decrease_duration(&ev, RC6_TOGGLE_END); |
| data->count = 0; |
| data->body = 0; |
| |
| switch (rc6_mode(data)) { |
| case RC6_MODE_0: |
| data->wanted_bits = RC6_0_NBITS; |
| break; |
| case RC6_MODE_6A: |
| data->wanted_bits = RC6_6A_NBITS; |
| break; |
| default: |
| IR_dprintk(1, "RC6 unknown mode\n"); |
| goto out; |
| } |
| goto again; |
| |
| case STATE_BODY_BIT_START: |
| if (eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) { |
| /* Discard LSB's that won't fit in data->body */ |
| if (data->count++ < CHAR_BIT * sizeof data->body) { |
| data->body <<= 1; |
| if (ev.pulse) |
| data->body |= 1; |
| } |
| data->state = STATE_BODY_BIT_END; |
| return 0; |
| } else if (RC6_MODE_6A == rc6_mode(data) && !ev.pulse && |
| geq_margin(ev.duration, RC6_SUFFIX_SPACE, RC6_UNIT / 2)) { |
| data->state = STATE_FINISHED; |
| goto again; |
| } |
| break; |
| |
| case STATE_BODY_BIT_END: |
| if (!is_transition(&ev, &dev->raw->prev_ev)) |
| break; |
| |
| if (data->count == data->wanted_bits) |
| data->state = STATE_FINISHED; |
| else |
| data->state = STATE_BODY_BIT_START; |
| |
| decrease_duration(&ev, RC6_BIT_END); |
| goto again; |
| |
| case STATE_FINISHED: |
| if (ev.pulse) |
| break; |
| |
| switch (rc6_mode(data)) { |
| case RC6_MODE_0: |
| scancode = data->body; |
| toggle = data->toggle; |
| protocol = RC_TYPE_RC6_0; |
| IR_dprintk(1, "RC6(0) scancode 0x%04x (toggle: %u)\n", |
| scancode, toggle); |
| break; |
| |
| case RC6_MODE_6A: |
| if (data->count > CHAR_BIT * sizeof data->body) { |
| IR_dprintk(1, "RC6 too many (%u) data bits\n", |
| data->count); |
| goto out; |
| } |
| |
| scancode = data->body; |
| switch (data->count) { |
| case 20: |
| protocol = RC_TYPE_RC6_6A_20; |
| toggle = 0; |
| break; |
| case 24: |
| protocol = RC_TYPE_RC6_6A_24; |
| toggle = 0; |
| break; |
| case 32: |
| if ((scancode & RC6_6A_LCC_MASK) == RC6_6A_MCE_CC) { |
| protocol = RC_TYPE_RC6_MCE; |
| toggle = !!(scancode & RC6_6A_MCE_TOGGLE_MASK); |
| scancode &= ~RC6_6A_MCE_TOGGLE_MASK; |
| } else { |
| protocol = RC_TYPE_RC6_6A_32; |
| toggle = 0; |
| } |
| break; |
| default: |
| IR_dprintk(1, "RC6(6A) unsupported length\n"); |
| goto out; |
| } |
| |
| IR_dprintk(1, "RC6(6A) proto 0x%04x, scancode 0x%08x (toggle: %u)\n", |
| protocol, scancode, toggle); |
| break; |
| default: |
| IR_dprintk(1, "RC6 unknown mode\n"); |
| goto out; |
| } |
| |
| rc_keydown(dev, protocol, scancode, toggle); |
| data->state = STATE_INACTIVE; |
| return 0; |
| } |
| |
| out: |
| IR_dprintk(1, "RC6 decode failed at state %i (%uus %s)\n", |
| data->state, TO_US(ev.duration), TO_STR(ev.pulse)); |
| data->state = STATE_INACTIVE; |
| return -EINVAL; |
| } |
| |
| static const struct ir_raw_timings_manchester ir_rc6_timings[4] = { |
| { |
| .leader = RC6_PREFIX_PULSE, |
| .pulse_space_start = 0, |
| .clock = RC6_UNIT, |
| .invert = 1, |
| .trailer_space = RC6_PREFIX_SPACE, |
| }, |
| { |
| .clock = RC6_UNIT, |
| .invert = 1, |
| }, |
| { |
| .clock = RC6_UNIT * 2, |
| .invert = 1, |
| }, |
| { |
| .clock = RC6_UNIT, |
| .invert = 1, |
| .trailer_space = RC6_SUFFIX_SPACE, |
| }, |
| }; |
| |
| /** |
| * ir_rc6_encode() - Encode a scancode as a stream of raw events |
| * |
| * @protocol: protocol to encode |
| * @scancode: scancode to encode |
| * @events: array of raw ir events to write into |
| * @max: maximum size of @events |
| * |
| * Returns: The number of events written. |
| * -ENOBUFS if there isn't enough space in the array to fit the |
| * encoding. In this case all @max events will have been written. |
| * -EINVAL if the scancode is ambiguous or invalid. |
| */ |
| static int ir_rc6_encode(enum rc_type protocol, u32 scancode, |
| struct ir_raw_event *events, unsigned int max) |
| { |
| int ret; |
| struct ir_raw_event *e = events; |
| |
| if (protocol == RC_TYPE_RC6_0) { |
| /* Modulate the preamble */ |
| ret = ir_raw_gen_manchester(&e, max, &ir_rc6_timings[0], 0, 0); |
| if (ret < 0) |
| return ret; |
| |
| /* Modulate the header (Start Bit & Mode-0) */ |
| ret = ir_raw_gen_manchester(&e, max - (e - events), |
| &ir_rc6_timings[1], |
| RC6_HEADER_NBITS, (1 << 3)); |
| if (ret < 0) |
| return ret; |
| |
| /* Modulate Trailer Bit */ |
| ret = ir_raw_gen_manchester(&e, max - (e - events), |
| &ir_rc6_timings[2], 1, 0); |
| if (ret < 0) |
| return ret; |
| |
| /* Modulate rest of the data */ |
| ret = ir_raw_gen_manchester(&e, max - (e - events), |
| &ir_rc6_timings[3], RC6_0_NBITS, |
| scancode); |
| if (ret < 0) |
| return ret; |
| |
| } else { |
| int bits; |
| |
| switch (protocol) { |
| case RC_TYPE_RC6_MCE: |
| case RC_TYPE_RC6_6A_32: |
| bits = 32; |
| break; |
| case RC_TYPE_RC6_6A_24: |
| bits = 24; |
| break; |
| case RC_TYPE_RC6_6A_20: |
| bits = 20; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| /* Modulate the preamble */ |
| ret = ir_raw_gen_manchester(&e, max, &ir_rc6_timings[0], 0, 0); |
| if (ret < 0) |
| return ret; |
| |
| /* Modulate the header (Start Bit & Header-version 6 */ |
| ret = ir_raw_gen_manchester(&e, max - (e - events), |
| &ir_rc6_timings[1], |
| RC6_HEADER_NBITS, (1 << 3 | 6)); |
| if (ret < 0) |
| return ret; |
| |
| /* Modulate Trailer Bit */ |
| ret = ir_raw_gen_manchester(&e, max - (e - events), |
| &ir_rc6_timings[2], 1, 0); |
| if (ret < 0) |
| return ret; |
| |
| /* Modulate rest of the data */ |
| ret = ir_raw_gen_manchester(&e, max - (e - events), |
| &ir_rc6_timings[3], |
| bits, |
| scancode); |
| if (ret < 0) |
| return ret; |
| } |
| |
| return e - events; |
| } |
| |
| static struct ir_raw_handler rc6_handler = { |
| .protocols = RC_BIT_RC6_0 | RC_BIT_RC6_6A_20 | |
| RC_BIT_RC6_6A_24 | RC_BIT_RC6_6A_32 | |
| RC_BIT_RC6_MCE, |
| .decode = ir_rc6_decode, |
| .encode = ir_rc6_encode, |
| }; |
| |
| static int __init ir_rc6_decode_init(void) |
| { |
| ir_raw_handler_register(&rc6_handler); |
| |
| printk(KERN_INFO "IR RC6 protocol handler initialized\n"); |
| return 0; |
| } |
| |
| static void __exit ir_rc6_decode_exit(void) |
| { |
| ir_raw_handler_unregister(&rc6_handler); |
| } |
| |
| module_init(ir_rc6_decode_init); |
| module_exit(ir_rc6_decode_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("David Härdeman <david@hardeman.nu>"); |
| MODULE_DESCRIPTION("RC6 IR protocol decoder"); |