/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol * * Copyright (C) 2013-2014 Imagination Technologies Ltd. * * Based on NEC decoder: * Copyright (C) 2010 by Mauro Carvalho Chehab * * 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 #include #include "rc-core-priv.h" #define SHARP_NBITS 15 #define SHARP_UNIT 40000 /* ns */ #define SHARP_BIT_PULSE (8 * SHARP_UNIT) /* 320us */ #define SHARP_BIT_0_PERIOD (25 * SHARP_UNIT) /* 1ms (680us space) */ #define SHARP_BIT_1_PERIOD (50 * SHARP_UNIT) /* 2ms (1680ms space) */ #define SHARP_ECHO_SPACE (1000 * SHARP_UNIT) /* 40 ms */ #define SHARP_TRAILER_SPACE (125 * SHARP_UNIT) /* 5 ms (even longer) */ enum sharp_state { STATE_INACTIVE, STATE_BIT_PULSE, STATE_BIT_SPACE, STATE_TRAILER_PULSE, STATE_ECHO_SPACE, STATE_TRAILER_SPACE, }; /** * ir_sharp_decode() - Decode one Sharp pulse or space * @dev: the struct rc_dev descriptor of the device * @duration: the struct ir_raw_event descriptor of the pulse/space * * This function returns -EINVAL if the pulse violates the state machine */ static int ir_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev) { struct sharp_dec *data = &dev->raw->sharp; u32 msg, echo, address, command, scancode; if (!is_timing_event(ev)) { if (ev.reset) data->state = STATE_INACTIVE; return 0; } IR_dprintk(2, "Sharp decode started at state %d (%uus %s)\n", data->state, TO_US(ev.duration), TO_STR(ev.pulse)); switch (data->state) { case STATE_INACTIVE: if (!ev.pulse) break; if (!eq_margin(ev.duration, SHARP_BIT_PULSE, SHARP_BIT_PULSE / 2)) break; data->count = 0; data->pulse_len = ev.duration; data->state = STATE_BIT_SPACE; return 0; case STATE_BIT_PULSE: if (!ev.pulse) break; if (!eq_margin(ev.duration, SHARP_BIT_PULSE, SHARP_BIT_PULSE / 2)) break; data->pulse_len = ev.duration; data->state = STATE_BIT_SPACE; return 0; case STATE_BIT_SPACE: if (ev.pulse) break; data->bits <<= 1; if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD, SHARP_BIT_PULSE * 2)) data->bits |= 1; else if (!eq_margin(data->pulse_len + ev.duration, SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2)) break; data->count++; if (data->count == SHARP_NBITS || data->count == SHARP_NBITS * 2) data->state = STATE_TRAILER_PULSE; else data->state = STATE_BIT_PULSE; return 0; case STATE_TRAILER_PULSE: if (!ev.pulse) break; if (!eq_margin(ev.duration, SHARP_BIT_PULSE, SHARP_BIT_PULSE / 2)) break; if (data->count == SHARP_NBITS) { /* exp,chk bits should be 1,0 */ if ((data->bits & 0x3) != 0x2 && /* DENON variant, both chk bits 0 */ (data->bits & 0x3) != 0x0) break; data->state = STATE_ECHO_SPACE; } else { data->state = STATE_TRAILER_SPACE; } return 0; case STATE_ECHO_SPACE: if (ev.pulse) break; if (!eq_margin(ev.duration, SHARP_ECHO_SPACE, SHARP_ECHO_SPACE / 4)) break; data->state = STATE_BIT_PULSE; return 0; case STATE_TRAILER_SPACE: if (ev.pulse) break; if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE, SHARP_BIT_PULSE / 2)) break; /* Validate - command, ext, chk should be inverted in 2nd */ msg = (data->bits >> 15) & 0x7fff; echo = data->bits & 0x7fff; if ((msg ^ echo) != 0x3ff) { IR_dprintk(1, "Sharp checksum error: received 0x%04x, 0x%04x\n", msg, echo); break; } address = bitrev8((msg >> 7) & 0xf8); command = bitrev8((msg >> 2) & 0xff); scancode = address << 8 | command; IR_dprintk(1, "Sharp scancode 0x%04x\n", scancode); rc_keydown(dev, RC_PROTO_SHARP, scancode, 0); data->state = STATE_INACTIVE; return 0; } IR_dprintk(1, "Sharp decode failed at count %d state %d (%uus %s)\n", data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse)); data->state = STATE_INACTIVE; return -EINVAL; } static const struct ir_raw_timings_pd ir_sharp_timings = { .header_pulse = 0, .header_space = 0, .bit_pulse = SHARP_BIT_PULSE, .bit_space[0] = SHARP_BIT_0_PERIOD, .bit_space[1] = SHARP_BIT_1_PERIOD, .trailer_pulse = SHARP_BIT_PULSE, .trailer_space = SHARP_ECHO_SPACE, .msb_first = 1, }; /** * ir_sharp_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. */ static int ir_sharp_encode(enum rc_proto protocol, u32 scancode, struct ir_raw_event *events, unsigned int max) { struct ir_raw_event *e = events; int ret; u32 raw; raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) | bitrev8(scancode); ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS, (raw << 2) | 2); if (ret < 0) return ret; max -= ret; raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) | bitrev8(~scancode); ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS, (raw << 2) | 1); if (ret < 0) return ret; return e - events; } static struct ir_raw_handler sharp_handler = { .protocols = RC_PROTO_BIT_SHARP, .decode = ir_sharp_decode, .encode = ir_sharp_encode, }; static int __init ir_sharp_decode_init(void) { ir_raw_handler_register(&sharp_handler); pr_info("IR Sharp protocol handler initialized\n"); return 0; } static void __exit ir_sharp_decode_exit(void) { ir_raw_handler_unregister(&sharp_handler); } module_init(ir_sharp_decode_init); module_exit(ir_sharp_decode_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("James Hogan "); MODULE_DESCRIPTION("Sharp IR protocol decoder");