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1// SPDX-License-Identifier: GPL-2.0-only2/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol3 *4 * Copyright (C) 2013-2014 Imagination Technologies Ltd.5 *6 * Based on NEC decoder:7 * Copyright (C) 2010 by Mauro Carvalho Chehab8 */9 10#include <linux/bitrev.h>11#include <linux/module.h>12#include "rc-core-priv.h"13 14#define SHARP_NBITS 1515#define SHARP_UNIT 40 /* us */16#define SHARP_BIT_PULSE (8 * SHARP_UNIT) /* 320us */17#define SHARP_BIT_0_PERIOD (25 * SHARP_UNIT) /* 1ms (680us space) */18#define SHARP_BIT_1_PERIOD (50 * SHARP_UNIT) /* 2ms (1680us space) */19#define SHARP_BIT_0_SPACE (17 * SHARP_UNIT) /* 680us space */20#define SHARP_BIT_1_SPACE (42 * SHARP_UNIT) /* 1680us space */21#define SHARP_ECHO_SPACE (1000 * SHARP_UNIT) /* 40 ms */22#define SHARP_TRAILER_SPACE (125 * SHARP_UNIT) /* 5 ms (even longer) */23 24enum sharp_state {25 STATE_INACTIVE,26 STATE_BIT_PULSE,27 STATE_BIT_SPACE,28 STATE_TRAILER_PULSE,29 STATE_ECHO_SPACE,30 STATE_TRAILER_SPACE,31};32 33/**34 * ir_sharp_decode() - Decode one Sharp pulse or space35 * @dev: the struct rc_dev descriptor of the device36 * @ev: the struct ir_raw_event descriptor of the pulse/space37 *38 * This function returns -EINVAL if the pulse violates the state machine39 */40static int ir_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)41{42 struct sharp_dec *data = &dev->raw->sharp;43 u32 msg, echo, address, command, scancode;44 45 if (!is_timing_event(ev)) {46 if (ev.overflow)47 data->state = STATE_INACTIVE;48 return 0;49 }50 51 dev_dbg(&dev->dev, "Sharp decode started at state %d (%uus %s)\n",52 data->state, ev.duration, TO_STR(ev.pulse));53 54 switch (data->state) {55 56 case STATE_INACTIVE:57 if (!ev.pulse)58 break;59 60 if (!eq_margin(ev.duration, SHARP_BIT_PULSE,61 SHARP_BIT_PULSE / 2))62 break;63 64 data->count = 0;65 data->pulse_len = ev.duration;66 data->state = STATE_BIT_SPACE;67 return 0;68 69 case STATE_BIT_PULSE:70 if (!ev.pulse)71 break;72 73 if (!eq_margin(ev.duration, SHARP_BIT_PULSE,74 SHARP_BIT_PULSE / 2))75 break;76 77 data->pulse_len = ev.duration;78 data->state = STATE_BIT_SPACE;79 return 0;80 81 case STATE_BIT_SPACE:82 if (ev.pulse)83 break;84 85 data->bits <<= 1;86 if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,87 SHARP_BIT_PULSE * 2))88 data->bits |= 1;89 else if (!eq_margin(data->pulse_len + ev.duration,90 SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))91 break;92 data->count++;93 94 if (data->count == SHARP_NBITS ||95 data->count == SHARP_NBITS * 2)96 data->state = STATE_TRAILER_PULSE;97 else98 data->state = STATE_BIT_PULSE;99 100 return 0;101 102 case STATE_TRAILER_PULSE:103 if (!ev.pulse)104 break;105 106 if (!eq_margin(ev.duration, SHARP_BIT_PULSE,107 SHARP_BIT_PULSE / 2))108 break;109 110 if (data->count == SHARP_NBITS) {111 /* exp,chk bits should be 1,0 */112 if ((data->bits & 0x3) != 0x2 &&113 /* DENON variant, both chk bits 0 */114 (data->bits & 0x3) != 0x0)115 break;116 data->state = STATE_ECHO_SPACE;117 } else {118 data->state = STATE_TRAILER_SPACE;119 }120 return 0;121 122 case STATE_ECHO_SPACE:123 if (ev.pulse)124 break;125 126 if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,127 SHARP_ECHO_SPACE / 4))128 break;129 130 data->state = STATE_BIT_PULSE;131 132 return 0;133 134 case STATE_TRAILER_SPACE:135 if (ev.pulse)136 break;137 138 if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,139 SHARP_BIT_PULSE / 2))140 break;141 142 /* Validate - command, ext, chk should be inverted in 2nd */143 msg = (data->bits >> 15) & 0x7fff;144 echo = data->bits & 0x7fff;145 if ((msg ^ echo) != 0x3ff) {146 dev_dbg(&dev->dev,147 "Sharp checksum error: received 0x%04x, 0x%04x\n",148 msg, echo);149 break;150 }151 152 address = bitrev8((msg >> 7) & 0xf8);153 command = bitrev8((msg >> 2) & 0xff);154 155 scancode = address << 8 | command;156 dev_dbg(&dev->dev, "Sharp scancode 0x%04x\n", scancode);157 158 rc_keydown(dev, RC_PROTO_SHARP, scancode, 0);159 data->state = STATE_INACTIVE;160 return 0;161 }162 163 dev_dbg(&dev->dev, "Sharp decode failed at count %d state %d (%uus %s)\n",164 data->count, data->state, ev.duration, TO_STR(ev.pulse));165 data->state = STATE_INACTIVE;166 return -EINVAL;167}168 169static const struct ir_raw_timings_pd ir_sharp_timings = {170 .header_pulse = 0,171 .header_space = 0,172 .bit_pulse = SHARP_BIT_PULSE,173 .bit_space[0] = SHARP_BIT_0_SPACE,174 .bit_space[1] = SHARP_BIT_1_SPACE,175 .trailer_pulse = SHARP_BIT_PULSE,176 .trailer_space = SHARP_ECHO_SPACE,177 .msb_first = 1,178};179 180/**181 * ir_sharp_encode() - Encode a scancode as a stream of raw events182 *183 * @protocol: protocol to encode184 * @scancode: scancode to encode185 * @events: array of raw ir events to write into186 * @max: maximum size of @events187 *188 * Returns: The number of events written.189 * -ENOBUFS if there isn't enough space in the array to fit the190 * encoding. In this case all @max events will have been written.191 */192static int ir_sharp_encode(enum rc_proto protocol, u32 scancode,193 struct ir_raw_event *events, unsigned int max)194{195 struct ir_raw_event *e = events;196 int ret;197 u32 raw;198 199 raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |200 bitrev8(scancode);201 ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,202 (raw << 2) | 2);203 if (ret < 0)204 return ret;205 206 max -= ret;207 208 raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |209 bitrev8(~scancode);210 ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,211 (raw << 2) | 1);212 if (ret < 0)213 return ret;214 215 return e - events;216}217 218static struct ir_raw_handler sharp_handler = {219 .protocols = RC_PROTO_BIT_SHARP,220 .decode = ir_sharp_decode,221 .encode = ir_sharp_encode,222 .carrier = 38000,223 .min_timeout = SHARP_ECHO_SPACE + SHARP_ECHO_SPACE / 4,224};225 226static int __init ir_sharp_decode_init(void)227{228 ir_raw_handler_register(&sharp_handler);229 230 pr_info("IR Sharp protocol handler initialized\n");231 return 0;232}233 234static void __exit ir_sharp_decode_exit(void)235{236 ir_raw_handler_unregister(&sharp_handler);237}238 239module_init(ir_sharp_decode_init);240module_exit(ir_sharp_decode_exit);241 242MODULE_LICENSE("GPL");243MODULE_AUTHOR("James Hogan <jhogan@kernel.org>");244MODULE_DESCRIPTION("Sharp IR protocol decoder");245