rc/img-ir/img-ir-nec.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * ImgTec IR Decoder setup for NEC protocol.
0004  *
0005  * Copyright 2010-2014 Imagination Technologies Ltd.
0006  */
0007
0008 #include "img-ir-hw.h"
0009 #include <linux/bitrev.h>
0010 #include <linux/log2.h>
0011
0012 /* Convert NEC data to a scancode */
0013 static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
0014                    struct img_ir_scancode_req *request)
0015 {
0016     unsigned int addr, addr_inv, data, data_inv;
0017     /* a repeat code has no data */
0018     if (!len)
0019         return IMG_IR_REPEATCODE;
0020     if (len != 32)
0021         return -EINVAL;
0022     /* raw encoding: ddDDaaAA */
0023     addr     = (raw >>  0) & 0xff;
0024     addr_inv = (raw >>  8) & 0xff;
0025     data     = (raw >> 16) & 0xff;
0026     data_inv = (raw >> 24) & 0xff;
0027     if ((data_inv ^ data) != 0xff) {
0028         /* 32-bit NEC (used by Apple and TiVo remotes) */
0029         /* scan encoding: as transmitted, MSBit = first received bit */
0030         request->scancode = bitrev8(addr)     << 24 |
0031                 bitrev8(addr_inv) << 16 |
0032                 bitrev8(data)     <<  8 |
0033                 bitrev8(data_inv);
0034         request->protocol = RC_PROTO_NEC32;
0035     } else if ((addr_inv ^ addr) != 0xff) {
0036         /* Extended NEC */
0037         /* scan encoding: AAaaDD */
0038         request->scancode = addr     << 16 |
0039                 addr_inv <<  8 |
0040                 data;
0041         request->protocol = RC_PROTO_NECX;
0042     } else {
0043         /* Normal NEC */
0044         /* scan encoding: AADD */
0045         request->scancode = addr << 8 |
0046                 data;
0047         request->protocol = RC_PROTO_NEC;
0048     }
0049     return IMG_IR_SCANCODE;
0050 }
0051
0052 /* Convert NEC scancode to NEC data filter */
0053 static int img_ir_nec_filter(const struct rc_scancode_filter *in,
0054                  struct img_ir_filter *out, u64 protocols)
0055 {
0056     unsigned int addr, addr_inv, data, data_inv;
0057     unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
0058
0059     data       = in->data & 0xff;
0060     data_m     = in->mask & 0xff;
0061
0062     protocols &= RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32;
0063
0064     /*
0065      * If only one bit is set, we were requested to do an exact
0066      * protocol. This should be the case for wakeup filters; for
0067      * normal filters, guess the protocol from the scancode.
0068      */
0069     if (!is_power_of_2(protocols)) {
0070         if ((in->data | in->mask) & 0xff000000)
0071             protocols = RC_PROTO_BIT_NEC32;
0072         else if ((in->data | in->mask) & 0x00ff0000)
0073             protocols = RC_PROTO_BIT_NECX;
0074         else
0075             protocols = RC_PROTO_BIT_NEC;
0076     }
0077
0078     if (protocols == RC_PROTO_BIT_NEC32) {
0079         /* 32-bit NEC (used by Apple and TiVo remotes) */
0080         /* scan encoding: as transmitted, MSBit = first received bit */
0081         addr       = bitrev8(in->data >> 24);
0082         addr_m     = bitrev8(in->mask >> 24);
0083         addr_inv   = bitrev8(in->data >> 16);
0084         addr_inv_m = bitrev8(in->mask >> 16);
0085         data       = bitrev8(in->data >>  8);
0086         data_m     = bitrev8(in->mask >>  8);
0087         data_inv   = bitrev8(in->data >>  0);
0088         data_inv_m = bitrev8(in->mask >>  0);
0089     } else if (protocols == RC_PROTO_BIT_NECX) {
0090         /* Extended NEC */
0091         /* scan encoding AAaaDD */
0092         addr       = (in->data >> 16) & 0xff;
0093         addr_m     = (in->mask >> 16) & 0xff;
0094         addr_inv   = (in->data >>  8) & 0xff;
0095         addr_inv_m = (in->mask >>  8) & 0xff;
0096         data_inv   = data ^ 0xff;
0097         data_inv_m = data_m;
0098     } else {
0099         /* Normal NEC */
0100         /* scan encoding: AADD */
0101         addr       = (in->data >>  8) & 0xff;
0102         addr_m     = (in->mask >>  8) & 0xff;
0103         addr_inv   = addr ^ 0xff;
0104         addr_inv_m = addr_m;
0105         data_inv   = data ^ 0xff;
0106         data_inv_m = data_m;
0107     }
0108
0109     /* raw encoding: ddDDaaAA */
0110     out->data = data_inv << 24 |
0111             data     << 16 |
0112             addr_inv <<  8 |
0113             addr;
0114     out->mask = data_inv_m << 24 |
0115             data_m     << 16 |
0116             addr_inv_m <<  8 |
0117             addr_m;
0118     return 0;
0119 }
0120
0121 /*
0122  * NEC decoder
0123  * See also http://www.sbprojects.com/knowledge/ir/nec.php
0124  *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
0125  */
0126 struct img_ir_decoder img_ir_nec = {
0127     .type = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32,
0128     .control = {
0129         .decoden = 1,
0130         .code_type = IMG_IR_CODETYPE_PULSEDIST,
0131     },
0132     /* main timings */
0133     .unit = 562500, /* 562.5 us */
0134     .timings = {
0135         /* leader symbol */
0136         .ldr = {
0137             .pulse = { 16   /* 9ms */ },
0138             .space = { 8    /* 4.5ms */ },
0139         },
0140         /* 0 symbol */
0141         .s00 = {
0142             .pulse = { 1    /* 562.5 us */ },
0143             .space = { 1    /* 562.5 us */ },
0144         },
0145         /* 1 symbol */
0146         .s01 = {
0147             .pulse = { 1    /* 562.5 us */ },
0148             .space = { 3    /* 1687.5 us */ },
0149         },
0150         /* free time */
0151         .ft = {
0152             .minlen = 32,
0153             .maxlen = 32,
0154             .ft_min = 10,   /* 5.625 ms */
0155         },
0156     },
0157     /* repeat codes */
0158     .repeat = 108,          /* 108 ms */
0159     .rtimings = {
0160         /* leader symbol */
0161         .ldr = {
0162             .space = { 4    /* 2.25 ms */ },
0163         },
0164         /* free time */
0165         .ft = {
0166             .minlen = 0,    /* repeat code has no data */
0167             .maxlen = 0,
0168         },
0169     },
0170     /* scancode logic */
0171     .scancode = img_ir_nec_scancode,
0172     .filter = img_ir_nec_filter,
0173 };