Relocate platform specific drivers (#13894)

* Relocate platform specific drivers

* Move stm eeprom

* Tidy up slightly

platforms/avr/drivers/i2c_slave.h

@@ -0,0 +1,41 @@
+/*  Copyright (C) 2019 Elia Ritterbusch
+ +
+ *  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 3 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 <https://www.gnu.org/licenses/>.
+ */
+/* Library made by: g4lvanix
+ * GitHub repository: https://github.com/g4lvanix/I2C-slave-lib
+
+ Info: Inititate the library by giving the required address.
+       Read or write to the necessary buffer according to the opperation.
+ */
+
+#pragma once
+
+#ifndef I2C_SLAVE_REG_COUNT
+
+#    if defined(USE_I2C) && defined(SPLIT_COMMON_TRANSACTIONS)
+#        include "transport.h"
+#        define I2C_SLAVE_REG_COUNT sizeof(split_shared_memory_t)
+#    else  // defined(USE_I2C) && defined(SPLIT_COMMON_TRANSACTIONS)
+#        define I2C_SLAVE_REG_COUNT 30
+#    endif  // defined(USE_I2C) && defined(SPLIT_COMMON_TRANSACTIONS)
+
+#endif  // I2C_SLAVE_REG_COUNT
+
+_Static_assert(I2C_SLAVE_REG_COUNT < 256, "I2C target registers must be single byte");
+
+extern volatile uint8_t i2c_slave_reg[I2C_SLAVE_REG_COUNT];
+
+void i2c_slave_init(uint8_t address);
+void i2c_slave_stop(void);