// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ImgTec IR Decoder setup for NEC protocol.
 *
 * Copyright 2010-2014 Imagination Technologies Ltd.
 */

#include "img-ir-hw.h"
#include <linux/bitrev.h>
#include <linux/log2.h>

/* Convert NEC data to a scancode */
static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
                               struct img_ir_scancode_req *request)
{
        unsigned int addr, addr_inv, data, data_inv;
        /* a repeat code has no data */
        if (!len)
                return IMG_IR_REPEATCODE;
        if (len != 32)
                return -EINVAL;
        /* raw encoding: ddDDaaAA */
        addr     = (raw >>  0) & 0xff;
        addr_inv = (raw >>  8) & 0xff;
        data     = (raw >> 16) & 0xff;
        data_inv = (raw >> 24) & 0xff;
        if ((data_inv ^ data) != 0xff) {
                /* 32-bit NEC (used by Apple and TiVo remotes) */
                /* scan encoding: as transmitted, MSBit = first received bit */
                request->scancode = bitrev8(addr)     << 24 |
                                bitrev8(addr_inv) << 16 |
                                bitrev8(data)     <<  8 |
                                bitrev8(data_inv);
                request->protocol = RC_PROTO_NEC32;
        } else if ((addr_inv ^ addr) != 0xff) {
                /* Extended NEC */
                /* scan encoding: AAaaDD */
                request->scancode = addr     << 16 |
                                addr_inv <<  8 |
                                data;
                request->protocol = RC_PROTO_NECX;
        } else {
                /* Normal NEC */
                /* scan encoding: AADD */
                request->scancode = addr << 8 |
                                data;
                request->protocol = RC_PROTO_NEC;
        }
        return IMG_IR_SCANCODE;
}

/* Convert NEC scancode to NEC data filter */
static int img_ir_nec_filter(const struct rc_scancode_filter *in,
                             struct img_ir_filter *out, u64 protocols)
{
        unsigned int addr, addr_inv, data, data_inv;
        unsigned int addr_m, addr_inv_m, data_m, data_inv_m;

        data       = in->data & 0xff;
        data_m     = in->mask & 0xff;

        protocols &= RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32;

        /*
         * If only one bit is set, we were requested to do an exact
         * protocol. This should be the case for wakeup filters; for
         * normal filters, guess the protocol from the scancode.
         */
        if (!is_power_of_2(protocols)) {
                if ((in->data | in->mask) & 0xff000000)
                        protocols = RC_PROTO_BIT_NEC32;
                else if ((in->data | in->mask) & 0x00ff0000)
                        protocols = RC_PROTO_BIT_NECX;
                else
                        protocols = RC_PROTO_BIT_NEC;
        }

        if (protocols == RC_PROTO_BIT_NEC32) {
                /* 32-bit NEC (used by Apple and TiVo remotes) */
                /* scan encoding: as transmitted, MSBit = first received bit */
                addr       = bitrev8(in->data >> 24);
                addr_m     = bitrev8(in->mask >> 24);
                addr_inv   = bitrev8(in->data >> 16);
                addr_inv_m = bitrev8(in->mask >> 16);
                data       = bitrev8(in->data >>  8);
                data_m     = bitrev8(in->mask >>  8);
                data_inv   = bitrev8(in->data >>  0);
                data_inv_m = bitrev8(in->mask >>  0);
        } else if (protocols == RC_PROTO_BIT_NECX) {
                /* Extended NEC */
                /* scan encoding AAaaDD */
                addr       = (in->data >> 16) & 0xff;
                addr_m     = (in->mask >> 16) & 0xff;
                addr_inv   = (in->data >>  8) & 0xff;
                addr_inv_m = (in->mask >>  8) & 0xff;
                data_inv   = data ^ 0xff;
                data_inv_m = data_m;
        } else {
                /* Normal NEC */
                /* scan encoding: AADD */
                addr       = (in->data >>  8) & 0xff;
                addr_m     = (in->mask >>  8) & 0xff;
                addr_inv   = addr ^ 0xff;
                addr_inv_m = addr_m;
                data_inv   = data ^ 0xff;
                data_inv_m = data_m;
        }

        /* raw encoding: ddDDaaAA */
        out->data = data_inv << 24 |
                    data     << 16 |
                    addr_inv <<  8 |
                    addr;
        out->mask = data_inv_m << 24 |
                    data_m     << 16 |
                    addr_inv_m <<  8 |
                    addr_m;
        return 0;
}

/*
 * NEC decoder
 * See also http://www.sbprojects.com/knowledge/ir/nec.php
 *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
 */
struct img_ir_decoder img_ir_nec = {
        .type = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32,
        .control = {
                .decoden = 1,
                .code_type = IMG_IR_CODETYPE_PULSEDIST,
        },
        /* main timings */
        .unit = 562500, /* 562.5 us */
        .timings = {
                /* leader symbol */
                .ldr = {
                        .pulse = { 16   /* 9ms */ },
                        .space = { 8    /* 4.5ms */ },
                },
                /* 0 symbol */
                .s00 = {
                        .pulse = { 1    /* 562.5 us */ },
                        .space = { 1    /* 562.5 us */ },
                },
                /* 1 symbol */
                .s01 = {
                        .pulse = { 1    /* 562.5 us */ },
                        .space = { 3    /* 1687.5 us */ },
                },
                /* free time */
                .ft = {
                        .minlen = 32,
                        .maxlen = 32,
                        .ft_min = 10,   /* 5.625 ms */
                },
        },
        /* repeat codes */
        .repeat = 108,                  /* 108 ms */
        .rtimings = {
                /* leader symbol */
                .ldr = {
                        .space = { 4    /* 2.25 ms */ },
                },
                /* free time */
                .ft = {
                        .minlen = 0,    /* repeat code has no data */
                        .maxlen = 0,
                },
        },
        /* scancode logic */
        .scancode = img_ir_nec_scancode,
        .filter = img_ir_nec_filter,
};