Add Djinn. (#17382)

* Add Djinn.

* Review comments.

* Further cleanup.

keyboards/tzarc/djinn/rev1/config.h

@@ -0,0 +1,35 @@
+// Copyright 2018-2022 Nick Brassel (@tzarc)
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+// Limit the backlight brightness
+#ifndef BACKLIGHT_LIMIT_VAL
+#    define BACKLIGHT_LIMIT_VAL 144
+#endif // BACKLIGHT_LIMIT_VAL
+
+// Split configuration
+#define SPLIT_HAND_PIN B11
+#ifdef USE_PLUG_DETECT_PIN
+#    define USB_VBUS_PIN B12
+#endif
+#define SERIAL_USART_DRIVER SD3
+#define SERIAL_USART_TX_PAL_MODE 7
+#define SOFT_SERIAL_PIN B9
+#ifndef SERIAL_USART_SPEED
+#    define SERIAL_USART_SPEED 640000
+#endif // SERIAL_USART_SPEED
+
+// RGB configuration
+#define RGBLED_NUM 84
+#define DRIVER_LED_TOTAL 84
+#define RGB_MATRIX_SPLIT \
+    { 42, 42 }
+#define RGB_POWER_ENABLE_PIN B1
+#define RGB_CURR_1500mA_OK_PIN B0
+#define RGB_CURR_3000mA_OK_PIN C5
+
+// EEPROM configuration
+#define EXTERNAL_EEPROM_SPI_SLAVE_SELECT_PIN B5
+#define EXTERNAL_EEPROM_SPI_CLOCK_DIVISOR 8 // (160MHz/8) => 20MHz
+#define EXTERNAL_EEPROM_BYTE_COUNT 8192
+#define EXTERNAL_EEPROM_PAGE_SIZE 64 // it's FRAM, so it doesn't actually matter, this just sets the RAM buffer size