Add tzarc/ghoul. (#18562)

Co-authored-by: Joel Challis <git@zvecr.com>
Co-authored-by: Drashna Jaelre <drashna@live.com>

keyboards/tzarc/ghoul/ghoul.c

@@ -0,0 +1,44 @@
+// Copyright 2018-2022 Nick Brassel (@tzarc)
+// SPDX-License-Identifier: GPL-3.0-or-later
+#include QMK_KEYBOARD_H
+#include "analog.h"
+#include "spi_master.h"
+
+void keyboard_post_init_kb(void) {
+    // Enable RGB current limiter and wait for a bit before allowing RGB to continue
+    setPinOutput(RGB_ENABLE_PIN);
+    writePinHigh(RGB_ENABLE_PIN);
+    wait_ms(20);
+
+    // Offload to the user func
+    keyboard_post_init_user();
+}
+
+void matrix_init_custom(void) {
+    // SPI Matrix
+    setPinOutput(SPI_MATRIX_CHIP_SELECT_PIN);
+    writePinHigh(SPI_MATRIX_CHIP_SELECT_PIN);
+    spi_init();
+
+    // Encoder pushbutton
+    setPinInputLow(ENCODER_PUSHBUTTON_PIN);
+}
+
+bool matrix_scan_custom(matrix_row_t current_matrix[]) {
+    static matrix_row_t temp_matrix[MATRIX_ROWS] = {0};
+
+    // Read from SPI the matrix
+    spi_start(SPI_MATRIX_CHIP_SELECT_PIN, false, 0, SPI_MATRIX_DIVISOR);
+    spi_receive((uint8_t*)temp_matrix, MATRIX_SHIFT_REGISTER_COUNT * sizeof(matrix_row_t));
+    spi_stop();
+
+    // Read from the encoder pushbutton
+    temp_matrix[5] = readPin(ENCODER_PUSHBUTTON_PIN) ? 1 : 0;
+
+    // Check if we've changed, return the last-read data
+    bool changed = memcmp(current_matrix, temp_matrix, sizeof(temp_matrix)) != 0;
+    if (changed) {
+        memcpy(current_matrix, temp_matrix, sizeof(temp_matrix));
+    }
+    return changed;
+}