[Keyboard] Add Meck TKL handwired (#15533)

* Add meck_tkl

* Fix configuration and pin assignment

* Rellocate A10 pin, as it is used by the USB DFU bootloader

* Add volume and media keys to the function keys layer

* Rellocate source files to the handwired keyboards folder and add documentation

* Review changes for PR
- Improve LAYOUT macro to match the keyboard layout.
- Use "kxy" as pin names on the LAYOUT macro.
- Remove unused mcuconf.h and halconf.h.
- Fix README.

* Improve layout macro naming

keyboards/handwired/meck_tkl/blackpill_f401/chconf.h

@@ -0,0 +1,39 @@
+/* Copyright 2020 QMK
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * This file was auto-generated by:
+ *    `qmk chibios-confmigrate -i keyboards/handwired/meck_tkl/chconf.h -r platforms/chibios/common/configs/chconf.h`
+ */
+
+#pragma once
+
+#define CH_CFG_ST_FREQUENCY 10000
+
+#define CH_CFG_FACTORY_OBJECTS_REGISTRY TRUE
+
+#define CH_CFG_FACTORY_GENERIC_BUFFERS TRUE
+
+#define CH_CFG_FACTORY_SEMAPHORES TRUE
+
+#define CH_CFG_FACTORY_MAILBOXES TRUE
+
+#define CH_CFG_FACTORY_OBJ_FIFOS TRUE
+
+#define CH_CFG_FACTORY_PIPES TRUE
+
+#include_next <chconf.h>
+

keyboards/handwired/meck_tkl/blackpill_f401/config.h

@@ -0,0 +1,14 @@
+// Copyright 2021 Gabriel Kim (@gabrielkim13)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#define MATRIX_ROW_PINS \
+    { B15, A8, A9, B14, A15, B3 }
+#define MATRIX_COL_PINS \
+    { B4, B5, B6, B7, B8, B9, A1, A2, A3, A4, A5, A6, A7, B0, B1, A0, B10 }
+#define UNUSED_PINS \
+    { A10, A11, A12, B2, B12, C14, C15 }
+
+#define LED_CAPS_LOCK_PIN C13
+#define LED_PIN_ON_STATE 0

keyboards/handwired/meck_tkl/blackpill_f401/rules.mk

@@ -0,0 +1,10 @@
+# MCU name
+MCU = STM32F401
+
+# Bootloader selection
+BOOTLOADER = stm32-dfu
+
+# Build Options
+#   change yes to no to disable
+#
+KEYBOARD_SHARED_EP = yes