Initial support for ALT v2 (#21754)

keyboards/drop/alt/v2/config.h

@@ -0,0 +1,29 @@
+// Copyright 2023 Massdrop, Inc.
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+#define ADC_BUFFER_DEPTH 4
+#define ADC_SAMPLING_RATE ADC_SMPR_SMP_601P5
+#define ADC_RESOLUTION ADC_CFGR_RES_12BITS
+
+#define I2C_DRIVER I2CD2
+#define I2C1_SCL_PIN A9
+#define I2C1_SDA_PIN A10
+
+#define EXTERNAL_EEPROM_I2C_BASE_ADDRESS 0b10101000
+#define EXTERNAL_EEPROM_WP_PIN B5
+#define EEPROM_I2C_24LC256
+
+#define DRIVER_ADDR_1 0b1010011
+#define DRIVER_ADDR_2 0b1011111
+#define DRIVER_COUNT 2
+#define RGB_MATRIX_LED_COUNT 111
+#define ISSI_PWM_FREQUENCY 0b010 // 26k
+
+#define RGB_DISABLE_WHEN_USB_SUSPENDED
+#define RGB_MATRIX_DEFAULT_VAL 100
+#define RGB_MATRIX_KEYPRESSES
+#define RGB_MATRIX_FRAMEBUFFER_EFFECTS
+
+#define RGB_MATRIX_CYCLE_ZONES_ENABLE
+#define RGB_MATRIX_CAPS_LOCK_INDEX 30