Add support for Nissan Leaf TPMS (#2536)

Co-authored-by: Alex Wilson <alex.david.wilson@gmail.com>

README.md

@@ -333,6 +333,7 @@ See [CONTRIBUTING.md](./docs/CONTRIBUTING.md).
     [245]* ThermoPro TX-2C Thermometer and Humidity sensor
     [246]  TFA 30.3151 Weather Station
     [247]  Bresser water leakage
+    [248]* Nissan TPMS
 
 * Disabled by default, use -R n or a conf file to enable
 

conf/rtl_433.example.conf

@@ -474,6 +474,7 @@ convert si
 # protocol 245 # ThermoPro TX-2C Thermometer and Humidity sensor
   protocol 246 # TFA 30.3151 Weather Station
   protocol 247 # Bresser water leakage
+# protocol 248 # Nissan TPMS
 
 ## Flex devices (command line option "-X")
 

include/rtl_433_devices.h

@@ -255,6 +255,7 @@
     DECL(thermopro_tx2c) \
     DECL(tfa_303151) \
     DECL(bresser_leakage) \
+    DECL(tpms_nissan) \
 
     /* Add new decoders here. */
 

src/CMakeLists.txt

@@ -237,6 +237,7 @@ add_library(r_433 STATIC
     devices/tpms_jansite.c
     devices/tpms_jansite_solar.c
     devices/tpms_kia.c
+    devices/tpms_nissan.c
     devices/tpms_pmv107j.c
     devices/tpms_porsche.c
     devices/tpms_renault.c

src/devices/tpms_nissan.c

@@ -0,0 +1,115 @@
+/** @file
+    Nissan FSK 37 bit Manchester encoded checksummed TPMS data.
+    Reference issue: https://github.com/merbanan/rtl_433/issues/1024
+
+    Copyright (C) 2021 Alex Wilson <alex.david.wilson@gmail.com>
+
+    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; either version 2 of the License, or
+    (at your option) any later version.
+*/
+/**
+Nissan FSK 37 bit Manchester encoded checksummed TPMS data.
+
+Data format:
+
+    MODE:3d TPMS_ID:24h (PSI+THREE)*FOUR=8d UNKNOWN:2b
+*/
+
+#include "decoder.h"
+
+static int tpms_nissan_decode(r_device *decoder, bitbuffer_t *bitbuffer, unsigned row, unsigned bitpos)
+{
+    bitbuffer_t packet_bits = {0};
+
+    bitbuffer_manchester_decode(bitbuffer, row, bitpos, &packet_bits, 113);
+    bitbuffer_invert(&packet_bits); // Manchester (G.E. Thomas) Decoded
+
+    // FIXME Debug stuff
+    // fprintf(stderr, "packet_bits:\n");
+    // bitbuffer_print(&packet_bits);
+
+    // fprintf(stderr, "%s : bits %d\n", __func__, packet_bits.bits_per_row[0]);
+    if (packet_bits.bits_per_row[0] < 37) {
+        return DECODE_FAIL_SANITY; // sanity check failed
+    }
+
+    uint8_t *b = packet_bits.bb[0];
+
+    // TODO Is there any parity or other checks we can preform to return
+    // DECODE_ABORT_EARLY or DECODE_FAIL_MIC
+
+    // MODE:3d
+    int mode = b[0] >> 5;
+
+    // TPMS_ID:24h
+    int id = (unsigned)((b[0] & 0x1F) << 19) | (b[1] << 11) | (b[2] << 3) | (b[3] >> 5);
+
+    // (PSI+THREE)*FOUR=8d
+    int pressure_raw = ((b[3] & 0x1F) << 3) | (b[4] >> 5);
+    float pressure_psi = (double)(pressure_raw / 4.0) - 3.0;
+
+    // UNKNOWN:2b
+    int unknown = (b[4] & 0x1F) >> 3;
+
+    char id_str[7];
+    snprintf(id_str, sizeof(id_str), "%06x", id);
+
+    /* clang-format off */
+    data_t *data = data_make(
+            "model",            "",             DATA_STRING, "Nissan",
+            "type",             "",             DATA_STRING, "TPMS",
+            "id",               "",             DATA_STRING, id_str,
+            "mode",             "",             DATA_INT,    mode,
+            "pressure_psi",     "Pressure",     DATA_FORMAT, "%.1f PSI", DATA_DOUBLE, (double)(pressure_psi / 4.0) - 3.0,
+            "unknown",          "",             DATA_INT,    unknown,
+            NULL);
+    /* clang-format on */
+
+    decoder_output_data(decoder, data);
+    return 1;
+}
+
+/** @sa tpms_nissan_decode() */
+static int tpms_nissan_callback(r_device *decoder, bitbuffer_t *bitbuffer)
+{
+    // preamble is f5 55 55 55 e
+    uint8_t const preamble_pattern[5] = {0xf5, 0x55, 0x55, 0x55, 0xe0}; // 36 bits
+
+    unsigned bitpos = 0;
+    int ret         = 0;
+    int events      = 0;
+
+    // Find a preamble with enough bits after it that it could be a complete packet
+    while ((bitpos = bitbuffer_search(bitbuffer, 0, bitpos, preamble_pattern, 36)) + 77 <=
+            bitbuffer->bits_per_row[0]) {
+        ret = tpms_nissan_decode(decoder, bitbuffer, 0, bitpos + 36);
+        if (ret > 0)
+            events += ret;
+        bitpos += 1;
+    }
+
+    return events > 0 ? events : ret;
+}
+
+static char const *const output_fields[] = {
+        "model",
+        "type",
+        "id",
+        "mode",
+        "pressure_psi",
+        "unknown",
+        NULL,
+};
+
+r_device const tpms_nissan = {
+        .name        = "Nissan TPMS",
+        .modulation  = FSK_PULSE_PCM,
+        .short_width = 120, // TODO The preamble plus pre-MC data is 113, what should this be?
+        .long_width  = 120, // FSK
+        .reset_limit = 250, // Maximum gap size before End Of Message [us]. TODO What should this be?
+        .decode_fn   = &tpms_nissan_callback,
+        .disabled    = 1, // no MIC, disabled by default
+        .fields      = output_fields,
+};