img-ir-nec.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * ImgTec IR Decoder setup for NEC protocol.
  4 *
  5 * Copyright 2010-2014 Imagination Technologies Ltd.
  6 */
  7
  8#include "img-ir-hw.h"
  9#include <linux/bitrev.h>
 10#include <linux/log2.h>
 11
 12/* Convert NEC data to a scancode */
 13static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
 14			       struct img_ir_scancode_req *request)
 15{
 16	unsigned int addr, addr_inv, data, data_inv;
 17	/* a repeat code has no data */
 18	if (!len)
 19		return IMG_IR_REPEATCODE;
 20	if (len != 32)
 21		return -EINVAL;
 22	/* raw encoding: ddDDaaAA */
 23	addr     = (raw >>  0) & 0xff;
 24	addr_inv = (raw >>  8) & 0xff;
 25	data     = (raw >> 16) & 0xff;
 26	data_inv = (raw >> 24) & 0xff;
 27	if ((data_inv ^ data) != 0xff) {
 28		/* 32-bit NEC (used by Apple and TiVo remotes) */
 29		/* scan encoding: as transmitted, MSBit = first received bit */
 30		request->scancode = bitrev8(addr)     << 24 |
 31				bitrev8(addr_inv) << 16 |
 32				bitrev8(data)     <<  8 |
 33				bitrev8(data_inv);
 34		request->protocol = RC_PROTO_NEC32;
 35	} else if ((addr_inv ^ addr) != 0xff) {
 36		/* Extended NEC */
 37		/* scan encoding: AAaaDD */
 38		request->scancode = addr     << 16 |
 39				addr_inv <<  8 |
 40				data;
 41		request->protocol = RC_PROTO_NECX;
 42	} else {
 43		/* Normal NEC */
 44		/* scan encoding: AADD */
 45		request->scancode = addr << 8 |
 46				data;
 47		request->protocol = RC_PROTO_NEC;
 48	}
 49	return IMG_IR_SCANCODE;
 50}
 51
 52/* Convert NEC scancode to NEC data filter */
 53static int img_ir_nec_filter(const struct rc_scancode_filter *in,
 54			     struct img_ir_filter *out, u64 protocols)
 55{
 56	unsigned int addr, addr_inv, data, data_inv;
 57	unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
 58
 59	data       = in->data & 0xff;
 60	data_m     = in->mask & 0xff;
 61
 62	protocols &= RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32;
 63
 64	/*
 65	 * If only one bit is set, we were requested to do an exact
 66	 * protocol. This should be the case for wakeup filters; for
 67	 * normal filters, guess the protocol from the scancode.
 68	 */
 69	if (!is_power_of_2(protocols)) {
 70		if ((in->data | in->mask) & 0xff000000)
 71			protocols = RC_PROTO_BIT_NEC32;
 72		else if ((in->data | in->mask) & 0x00ff0000)
 73			protocols = RC_PROTO_BIT_NECX;
 74		else
 75			protocols = RC_PROTO_BIT_NEC;
 76	}
 77
 78	if (protocols == RC_PROTO_BIT_NEC32) {
 79		/* 32-bit NEC (used by Apple and TiVo remotes) */
 80		/* scan encoding: as transmitted, MSBit = first received bit */
 81		addr       = bitrev8(in->data >> 24);
 82		addr_m     = bitrev8(in->mask >> 24);
 83		addr_inv   = bitrev8(in->data >> 16);
 84		addr_inv_m = bitrev8(in->mask >> 16);
 85		data       = bitrev8(in->data >>  8);
 86		data_m     = bitrev8(in->mask >>  8);
 87		data_inv   = bitrev8(in->data >>  0);
 88		data_inv_m = bitrev8(in->mask >>  0);
 89	} else if (protocols == RC_PROTO_BIT_NECX) {
 90		/* Extended NEC */
 91		/* scan encoding AAaaDD */
 92		addr       = (in->data >> 16) & 0xff;
 93		addr_m     = (in->mask >> 16) & 0xff;
 94		addr_inv   = (in->data >>  8) & 0xff;
 95		addr_inv_m = (in->mask >>  8) & 0xff;
 96		data_inv   = data ^ 0xff;
 97		data_inv_m = data_m;
 98	} else {
 99		/* Normal NEC */
100		/* scan encoding: AADD */
101		addr       = (in->data >>  8) & 0xff;
102		addr_m     = (in->mask >>  8) & 0xff;
103		addr_inv   = addr ^ 0xff;
104		addr_inv_m = addr_m;
105		data_inv   = data ^ 0xff;
106		data_inv_m = data_m;
107	}
108
109	/* raw encoding: ddDDaaAA */
110	out->data = data_inv << 24 |
111		    data     << 16 |
112		    addr_inv <<  8 |
113		    addr;
114	out->mask = data_inv_m << 24 |
115		    data_m     << 16 |
116		    addr_inv_m <<  8 |
117		    addr_m;
118	return 0;
119}
120
121/*
122 * NEC decoder
123 * See also http://www.sbprojects.com/knowledge/ir/nec.php
124 *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
125 */
126struct img_ir_decoder img_ir_nec = {
127	.type = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32,
128	.control = {
129		.decoden = 1,
130		.code_type = IMG_IR_CODETYPE_PULSEDIST,
131	},
132	/* main timings */
133	.unit = 562500, /* 562.5 us */
134	.timings = {
135		/* leader symbol */
136		.ldr = {
137			.pulse = { 16	/* 9ms */ },
138			.space = { 8	/* 4.5ms */ },
139		},
140		/* 0 symbol */
141		.s00 = {
142			.pulse = { 1	/* 562.5 us */ },
143			.space = { 1	/* 562.5 us */ },
144		},
145		/* 1 symbol */
146		.s01 = {
147			.pulse = { 1	/* 562.5 us */ },
148			.space = { 3	/* 1687.5 us */ },
149		},
150		/* free time */
151		.ft = {
152			.minlen = 32,
153			.maxlen = 32,
154			.ft_min = 10,	/* 5.625 ms */
155		},
156	},
157	/* repeat codes */
158	.repeat = 108,			/* 108 ms */
159	.rtimings = {
160		/* leader symbol */
161		.ldr = {
162			.space = { 4	/* 2.25 ms */ },
163		},
164		/* free time */
165		.ft = {
166			.minlen = 0,	/* repeat code has no data */
167			.maxlen = 0,
168		},
169	},
170	/* scancode logic */
171	.scancode = img_ir_nec_scancode,
172	.filter = img_ir_nec_filter,
173};