Keyboard: Refactor lets split to use split common code (#4536)

* Refactor lets split to use split common code

* Refactor lets split to use split common code

* Build fixes for OLED_sample keymap

* Build fixes for OLED_sample keymap - attempt to reduce firmware size

19 files changed, 19 insertions, 1107 deletions

diff --git a/keyboards/lets_split/config.h b/keyboards/lets_split/config.h
index c910d8f24..cfb6bf4ff 100644
--- a/keyboards/lets_split/config.h
+++ b/keyboards/lets_split/config.h
@@ -16,9 +16,6 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef CONFIG_H
-#define CONFIG_H
+#pragma once
 
 #include "config_common.h"
-
-#endif
diff --git a/keyboards/lets_split/eeprom-lefthand.eep b/keyboards/lets_split/eeprom-lefthand.eep
deleted file mode 100644
index bda23cdb6..000000000
--- a/keyboards/lets_split/eeprom-lefthand.eep
+++ /dev/null
@@ -1,2 +0,0 @@
-:0F000000000000000000000000000000000001F0
-:00000001FF
diff --git a/keyboards/lets_split/eeprom-righthand.eep b/keyboards/lets_split/eeprom-righthand.eep
deleted file mode 100644
index 549cd1ef0..000000000
--- a/keyboards/lets_split/eeprom-righthand.eep
+++ /dev/null
@@ -1,2 +0,0 @@
-:0F000000000000000000000000000000000000F1
-:00000001FF
diff --git a/keyboards/lets_split/i2c.c b/keyboards/lets_split/i2c.c
deleted file mode 100644
index 084c890c4..000000000
--- a/keyboards/lets_split/i2c.c
+++ /dev/null
@@ -1,162 +0,0 @@
-#include <util/twi.h>
-#include <avr/io.h>
-#include <stdlib.h>
-#include <avr/interrupt.h>
-#include <util/twi.h>
-#include <stdbool.h>
-#include "i2c.h"
-
-#ifdef USE_I2C
-
-// Limits the amount of we wait for any one i2c transaction.
-// Since were running SCL line 100kHz (=> 10μs/bit), and each transactions is
-// 9 bits, a single transaction will take around 90μs to complete.
-//
-// (F_CPU/SCL_CLOCK)  =>  # of μC cycles to transfer a bit
-// poll loop takes at least 8 clock cycles to execute
-#define I2C_LOOP_TIMEOUT (9+1)*(F_CPU/SCL_CLOCK)/8
-
-#define BUFFER_POS_INC() (slave_buffer_pos = (slave_buffer_pos+1)%SLAVE_BUFFER_SIZE)
-
-volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE];
-
-static volatile uint8_t slave_buffer_pos;
-static volatile bool slave_has_register_set = false;
-
-// Wait for an i2c operation to finish
-inline static
-void i2c_delay(void) {
-  uint16_t lim = 0;
-  while(!(TWCR & (1<<TWINT)) && lim < I2C_LOOP_TIMEOUT)
-    lim++;
-
-  // easier way, but will wait slightly longer
-  // _delay_us(100);
-}
-
-// Setup twi to run at 100kHz
-void i2c_master_init(void) {
-  // no prescaler
-  TWSR = 0;
-  // Set TWI clock frequency to SCL_CLOCK. Need TWBR>10.
-  // Check datasheets for more info.
-  TWBR = ((F_CPU/SCL_CLOCK)-16)/2;
-}
-
-// Start a transaction with the given i2c slave address. The direction of the
-// transfer is set with I2C_READ and I2C_WRITE.
-// returns: 0 => success
-//          1 => error
-uint8_t i2c_master_start(uint8_t address) {
-  TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTA);
-
-  i2c_delay();
-
-  // check that we started successfully
-  if ( (TW_STATUS != TW_START) && (TW_STATUS != TW_REP_START))
-    return 1;
-
-  TWDR = address;
-  TWCR = (1<<TWINT) | (1<<TWEN);
-
-  i2c_delay();
-
-  if ( (TW_STATUS != TW_MT_SLA_ACK) && (TW_STATUS != TW_MR_SLA_ACK) )
-    return 1; // slave did not acknowledge
-  else
-    return 0; // success
-}
-
-
-// Finish the i2c transaction.
-void i2c_master_stop(void) {
-  TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
-
-  uint16_t lim = 0;
-  while(!(TWCR & (1<<TWSTO)) && lim < I2C_LOOP_TIMEOUT)
-    lim++;
-}
-
-// Write one byte to the i2c slave.
-// returns 0 => slave ACK
-//         1 => slave NACK
-uint8_t i2c_master_write(uint8_t data) {
-  TWDR = data;
-  TWCR = (1<<TWINT) | (1<<TWEN);
-
-  i2c_delay();
-
-  // check if the slave acknowledged us
-  return (TW_STATUS == TW_MT_DATA_ACK) ? 0 : 1;
-}
-
-// Read one byte from the i2c slave. If ack=1 the slave is acknowledged,
-// if ack=0 the acknowledge bit is not set.
-// returns: byte read from i2c device
-uint8_t i2c_master_read(int ack) {
-  TWCR = (1<<TWINT) | (1<<TWEN) | (ack<<TWEA);
-
-  i2c_delay();
-  return TWDR;
-}
-
-void i2c_reset_state(void) {
-  TWCR = 0;
-}
-
-void i2c_slave_init(uint8_t address) {
-  TWAR = address << 0; // slave i2c address
-  // TWEN  - twi enable
-  // TWEA  - enable address acknowledgement
-  // TWINT - twi interrupt flag
-  // TWIE  - enable the twi interrupt
-  TWCR = (1<<TWIE) | (1<<TWEA) | (1<<TWINT) | (1<<TWEN);
-}
-
-ISR(TWI_vect);
-
-ISR(TWI_vect) {
-  uint8_t ack = 1;
-  switch(TW_STATUS) {
-    case TW_SR_SLA_ACK:
-      // this device has been addressed as a slave receiver
-      slave_has_register_set = false;
-      break;
-
-    case TW_SR_DATA_ACK:
-      // this device has received data as a slave receiver
-      // The first byte that we receive in this transaction sets the location
-      // of the read/write location of the slaves memory that it exposes over
-      // i2c.  After that, bytes will be written at slave_buffer_pos, incrementing
-      // slave_buffer_pos after each write.
-      if(!slave_has_register_set) {
-        slave_buffer_pos = TWDR;
-        // don't acknowledge the master if this memory loctaion is out of bounds
-        if ( slave_buffer_pos >= SLAVE_BUFFER_SIZE ) {
-          ack = 0;
-          slave_buffer_pos = 0;
-        }
-        slave_has_register_set = true;
-      } else {
-        i2c_slave_buffer[slave_buffer_pos] = TWDR;
-        BUFFER_POS_INC();
-      }
-      break;
-
-    case TW_ST_SLA_ACK:
-    case TW_ST_DATA_ACK:
-      // master has addressed this device as a slave transmitter and is
-      // requesting data.
-      TWDR = i2c_slave_buffer[slave_buffer_pos];
-      BUFFER_POS_INC();
-      break;
-
-    case TW_BUS_ERROR: // something went wrong, reset twi state
-      TWCR = 0;
-    default:
-      break;
-  }
-  // Reset everything, so we are ready for the next TWI interrupt
-  TWCR |= (1<<TWIE) | (1<<TWINT) | (ack<<TWEA) | (1<<TWEN);
-}
-#endif
diff --git a/keyboards/lets_split/i2c.h b/keyboards/lets_split/i2c.h
deleted file mode 100644
index c15b6bc50..000000000
--- a/keyboards/lets_split/i2c.h
+++ /dev/null
@@ -1,49 +0,0 @@
-#ifndef I2C_H
-#define I2C_H
-
-#include <stdint.h>
-
-#ifndef F_CPU
-#define F_CPU 16000000UL
-#endif
-
-#define I2C_READ 1
-#define I2C_WRITE 0
-
-#define I2C_ACK 1
-#define I2C_NACK 0
-
-#define SLAVE_BUFFER_SIZE 0x10
-
-// i2c SCL clock frequency
-#define SCL_CLOCK  400000L
-
-extern volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE];
-
-void i2c_master_init(void);
-uint8_t i2c_master_start(uint8_t address);
-void i2c_master_stop(void);
-uint8_t i2c_master_write(uint8_t data);
-uint8_t i2c_master_read(int);
-void i2c_reset_state(void);
-void i2c_slave_init(uint8_t address);
-
-
-static inline unsigned char i2c_start_read(unsigned char addr) {
-  return i2c_master_start((addr << 1) | I2C_READ);
-}
-
-static inline unsigned char i2c_start_write(unsigned char addr) {
-  return i2c_master_start((addr << 1) | I2C_WRITE);
-}
-
-// from SSD1306 scrips
-extern unsigned char i2c_rep_start(unsigned char addr);
-extern void i2c_start_wait(unsigned char addr);
-extern unsigned char i2c_readAck(void);
-extern unsigned char i2c_readNak(void);
-extern unsigned char i2c_read(unsigned char ack);
-
-#define i2c_read(ack)  (ack) ? i2c_readAck() : i2c_readNak();
-
-#endif
diff --git a/keyboards/lets_split/keymaps/OLED_sample/rules.mk b/keyboards/lets_split/keymaps/OLED_sample/rules.mk
index a14e84d4e..89ad61fbe 100644
--- a/keyboards/lets_split/keymaps/OLED_sample/rules.mk
+++ b/keyboards/lets_split/keymaps/OLED_sample/rules.mk
@@ -1,25 +1,22 @@
+SRC += ssd1306.c
 
 # Build Options
 #   change to "no" to disable the options, or define them in the Makefile in
 #   the appropriate keymap folder that will get included automatically
 #
 BOOTMAGIC_ENABLE = no       # Virtual DIP switch configuration(+1000)
-MOUSEKEY_ENABLE = yes       # Mouse keys(+4700)
+MOUSEKEY_ENABLE = no        # Mouse keys(+4700)
 EXTRAKEY_ENABLE = yes       # Audio control and System control(+450)
 CONSOLE_ENABLE = no         # Console for debug(+400)
-COMMAND_ENABLE = no        # Commands for debug and configuration
-NKRO_ENABLE = yes            # Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
-BACKLIGHT_ENABLE = no      # Enable keyboard backlight functionality
+COMMAND_ENABLE = no         # Commands for debug and configuration
+NKRO_ENABLE = yes           # Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
+BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
 MIDI_ENABLE = no            # MIDI controls
 AUDIO_ENABLE = no           # Audio output on port C6
 UNICODE_ENABLE = no         # Unicode
 BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
-RGBLIGHT_ENABLE = yes        # Enable WS2812 RGB underlight. 
-SWAP_HANDS_ENABLE = no        # Enable one-hand typing
+RGBLIGHT_ENABLE = yes       # Enable WS2812 RGB underlight.
+SWAP_HANDS_ENABLE = no      # Enable one-hand typing
 
 # Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
 SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
-
-ifndef QUANTUM_DIR
-	include ../../../../Makefile
-endif
\ No newline at end of file
diff --git a/keyboards/lets_split/lets_split.h b/keyboards/lets_split/lets_split.h
index bce0ecb19..9c46f382d 100644
--- a/keyboards/lets_split/lets_split.h
+++ b/keyboards/lets_split/lets_split.h
@@ -1,5 +1,4 @@
-#ifndef LETS_SPLIT_H
-#define LETS_SPLIT_H
+#pragma once
 
 #include "quantum.h"
 
@@ -27,5 +26,3 @@
     )
 
 #define LAYOUT_kc_ortho_4x12 LAYOUT_kc
-
-#endif
diff --git a/keyboards/lets_split/matrix.c b/keyboards/lets_split/matrix.c
deleted file mode 100644
index f753d234a..000000000
--- a/keyboards/lets_split/matrix.c
+++ /dev/null
@@ -1,470 +0,0 @@
-/*
-Copyright 2012 Jun Wako <wakojun@gmail.com>
-
-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/>.
-*/
-
-/*
- * scan matrix
- */
-#include <stdint.h>
-#include <stdbool.h>
-#include <avr/io.h>
-#include "wait.h"
-#include "print.h"
-#include "debug.h"
-#include "util.h"
-#include "matrix.h"
-#include "split_util.h"
-#include "pro_micro.h"
-#include "config.h"
-#include "timer.h"
-
-#ifdef USE_I2C
-#  include "i2c.h"
-#else // USE_SERIAL
-#  include "serial.h"
-#endif
-
-#ifndef DEBOUNCING_DELAY
-#   define DEBOUNCING_DELAY 5
-#endif
-
-#if (DEBOUNCING_DELAY > 0)
-    static uint16_t debouncing_time;
-    static bool debouncing = false;
-#endif
-
-#if (MATRIX_COLS <= 8)
-#    define print_matrix_header()  print("\nr/c 01234567\n")
-#    define print_matrix_row(row)  print_bin_reverse8(matrix_get_row(row))
-#    define matrix_bitpop(i)       bitpop(matrix[i])
-#    define ROW_SHIFTER ((uint8_t)1)
-#else
-#    error "Currently only supports 8 COLS"
-#endif
-static matrix_row_t matrix_debouncing[MATRIX_ROWS];
-
-#define ERROR_DISCONNECT_COUNT 5
-
-#define ROWS_PER_HAND (MATRIX_ROWS/2)
-
-static uint8_t error_count = 0;
-
-static const uint8_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS;
-static const uint8_t col_pins[MATRIX_COLS] = MATRIX_COL_PINS;
-
-/* matrix state(1:on, 0:off) */
-static matrix_row_t matrix[MATRIX_ROWS];
-static matrix_row_t matrix_debouncing[MATRIX_ROWS];
-
-#if (DIODE_DIRECTION == COL2ROW)
-    static void init_cols(void);
-    static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row);
-    static void unselect_rows(void);
-    static void select_row(uint8_t row);
-    static void unselect_row(uint8_t row);
-#elif (DIODE_DIRECTION == ROW2COL)
-    static void init_rows(void);
-    static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col);
-    static void unselect_cols(void);
-    static void unselect_col(uint8_t col);
-    static void select_col(uint8_t col);
-#endif
-
-__attribute__ ((weak))
-void matrix_init_kb(void) {
-    matrix_init_user();
-}
-
-__attribute__ ((weak))
-void matrix_scan_kb(void) {
-    matrix_scan_user();
-}
-
-__attribute__ ((weak))
-void matrix_init_user(void) {
-}
-
-__attribute__ ((weak))
-void matrix_scan_user(void) {
-}
-
-__attribute__ ((weak))
-void matrix_slave_scan_user(void) {
-}
-
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
-void matrix_init(void)
-{
-#ifdef DISABLE_JTAG
-  // JTAG disable for PORT F. write JTD bit twice within four cycles.
-  MCUCR |= (1<<JTD);
-  MCUCR |= (1<<JTD);
-#endif
-
-    debug_enable = true;
-    debug_matrix = true;
-    debug_mouse = true;
-    // initialize row and col
-#if (DIODE_DIRECTION == COL2ROW)
-    unselect_rows();
-    init_cols();
-#elif (DIODE_DIRECTION == ROW2COL)
-    unselect_cols();
-    init_rows();
-#endif
-
-    TX_RX_LED_INIT;
-
-    // initialize matrix state: all keys off
-    for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        matrix[i] = 0;
-        matrix_debouncing[i] = 0;
-    }
-
-    matrix_init_quantum();
-
-}
-
-uint8_t _matrix_scan(void)
-{
-    int offset = isLeftHand ? 0 : (ROWS_PER_HAND);
-#if (DIODE_DIRECTION == COL2ROW)
-    // Set row, read cols
-    for (uint8_t current_row = 0; current_row < ROWS_PER_HAND; current_row++) {
-#       if (DEBOUNCING_DELAY > 0)
-            bool matrix_changed = read_cols_on_row(matrix_debouncing+offset, current_row);
-
-            if (matrix_changed) {
-                debouncing = true;
-                debouncing_time = timer_read();
-            }
-
-#       else
-            read_cols_on_row(matrix+offset, current_row);
-#       endif
-
-    }
-
-#elif (DIODE_DIRECTION == ROW2COL)
-    // Set col, read rows
-    for (uint8_t current_col = 0; current_col < MATRIX_COLS; current_col++) {
-#       if (DEBOUNCING_DELAY > 0)
-            bool matrix_changed = read_rows_on_col(matrix_debouncing+offset, current_col);
-            if (matrix_changed) {
-                debouncing = true;
-                debouncing_time = timer_read();
-            }
-#       else
-             read_rows_on_col(matrix+offset, current_col);
-#       endif
-
-    }
-#endif
-
-#   if (DEBOUNCING_DELAY > 0)
-        if (debouncing && (timer_elapsed(debouncing_time) > DEBOUNCING_DELAY)) {
-            for (uint8_t i = 0; i < ROWS_PER_HAND; i++) {
-                matrix[i+offset] = matrix_debouncing[i+offset];
-            }
-            debouncing = false;
-        }
-#   endif
-
-    return 1;
-}
-
-#ifdef USE_I2C
-
-// Get rows from other half over i2c
-int i2c_transaction(void) {
-    int slaveOffset = (isLeftHand) ? (ROWS_PER_HAND) : 0;
-
-    int err = i2c_master_start(SLAVE_I2C_ADDRESS + I2C_WRITE);
-    if (err) goto i2c_error;
-
-    // start of matrix stored at 0x00
-    err = i2c_master_write(0x00);
-    if (err) goto i2c_error;
-
-    // Start read
-    err = i2c_master_start(SLAVE_I2C_ADDRESS + I2C_READ);
-    if (err) goto i2c_error;
-
-    if (!err) {
-        int i;
-        for (i = 0; i < ROWS_PER_HAND-1; ++i) {
-            matrix[slaveOffset+i] = i2c_master_read(I2C_ACK);
-        }
-        matrix[slaveOffset+i] = i2c_master_read(I2C_NACK);
-        i2c_master_stop();
-    } else {
-i2c_error: // the cable is disconnceted, or something else went wrong
-        i2c_reset_state();
-        return err;
-    }
-
-    return 0;
-}
-
-#else // USE_SERIAL
-
-int serial_transaction(void) {
-    int slaveOffset = (isLeftHand) ? (ROWS_PER_HAND) : 0;
-
-    if (serial_update_buffers()) {
-        return 1;
-    }
-
-    for (int i = 0; i < ROWS_PER_HAND; ++i) {
-        matrix[slaveOffset+i] = serial_slave_buffer[i];
-    }
-    return 0;
-}
-#endif
-
-uint8_t matrix_scan(void)
-{
-    uint8_t ret = _matrix_scan();
-
-#ifdef USE_I2C
-    if( i2c_transaction() ) {
-#else // USE_SERIAL
-    if( serial_transaction() ) {
-#endif
-        // turn on the indicator led when halves are disconnected
-        TXLED1;
-
-        error_count++;
-
-        if (error_count > ERROR_DISCONNECT_COUNT) {
-            // reset other half if disconnected
-            int slaveOffset = (isLeftHand) ? (ROWS_PER_HAND) : 0;
-            for (int i = 0; i < ROWS_PER_HAND; ++i) {
-                matrix[slaveOffset+i] = 0;
-            }
-        }
-    } else {
-        // turn off the indicator led on no error
-        TXLED0;
-        error_count = 0;
-    }
-    matrix_scan_quantum();
-    return ret;
-}
-
-void matrix_slave_scan(void) {
-    _matrix_scan();
-
-    int offset = (isLeftHand) ? 0 : ROWS_PER_HAND;
-
-#ifdef USE_I2C
-    for (int i = 0; i < ROWS_PER_HAND; ++i) {
-        i2c_slave_buffer[i] = matrix[offset+i];
-    }
-#else // USE_SERIAL
-    for (int i = 0; i < ROWS_PER_HAND; ++i) {
-        serial_slave_buffer[i] = matrix[offset+i];
-    }
-#endif
-    matrix_slave_scan_user();
-}
-
-bool matrix_is_modified(void)
-{
-    if (debouncing) return false;
-    return true;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & ((matrix_row_t)1<<col));
-}
-
-inline
-matrix_row_t matrix_get_row(uint8_t row)
-{
-    return matrix[row];
-}
-
-void matrix_print(void)
-{
-    print("\nr/c 0123456789ABCDEF\n");
-    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
-        phex(row); print(": ");
-        pbin_reverse16(matrix_get_row(row));
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop16(matrix[i]);
-    }
-    return count;
-}
-
-#if (DIODE_DIRECTION == COL2ROW)
-
-static void init_cols(void)
-{
-    for(uint8_t x = 0; x < MATRIX_COLS; x++) {
-        uint8_t pin = col_pins[x];
-        _SFR_IO8((pin >> 4) + 1) &= ~_BV(pin & 0xF); // IN
-        _SFR_IO8((pin >> 4) + 2) |=  _BV(pin & 0xF); // HI
-    }
-}
-
-static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row)
-{
-    // Store last value of row prior to reading
-    matrix_row_t last_row_value = current_matrix[current_row];
-
-    // Clear data in matrix row
-    current_matrix[current_row] = 0;
-
-    // Select row and wait for row selecton to stabilize
-    select_row(current_row);
-    wait_us(30);
-
-    // For each col...
-    for(uint8_t col_index = 0; col_index < MATRIX_COLS; col_index++) {
-
-        // Select the col pin to read (active low)
-        uint8_t pin = col_pins[col_index];
-        uint8_t pin_state = (_SFR_IO8(pin >> 4) & _BV(pin & 0xF));
-
-        // Populate the matrix row with the state of the col pin
-        current_matrix[current_row] |=  pin_state ? 0 : (ROW_SHIFTER << col_index);
-    }
-
-    // Unselect row
-    unselect_row(current_row);
-
-    return (last_row_value != current_matrix[current_row]);
-}
-
-static void select_row(uint8_t row)
-{
-    uint8_t pin = row_pins[row];
-    _SFR_IO8((pin >> 4) + 1) |=  _BV(pin & 0xF); // OUT
-    _SFR_IO8((pin >> 4) + 2) &= ~_BV(pin & 0xF); // LOW
-}
-
-static void unselect_row(uint8_t row)
-{
-    uint8_t pin = row_pins[row];
-    _SFR_IO8((pin >> 4) + 1) &= ~_BV(pin & 0xF); // IN
-    _SFR_IO8((pin >> 4) + 2) |=  _BV(pin & 0xF); // HI
-}
-
-static void unselect_rows(void)
-{
-    for(uint8_t x = 0; x < ROWS_PER_HAND; x++) {
-        uint8_t pin = row_pins[x];
-        _SFR_IO8((pin >> 4) + 1) &= ~_BV(pin & 0xF); // IN
-        _SFR_IO8((pin >> 4) + 2) |=  _BV(pin & 0xF); // HI
-    }
-}
-
-#elif (DIODE_DIRECTION == ROW2COL)
-
-static void init_rows(void)
-{
-    for(uint8_t x = 0; x < ROWS_PER_HAND; x++) {
-        uint8_t pin = row_pins[x];
-        _SFR_IO8((pin >> 4) + 1) &= ~_BV(pin & 0xF); // IN
-        _SFR_IO8((pin >> 4) + 2) |=  _BV(pin & 0xF); // HI
-    }
-}
-
-static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col)
-{
-    bool matrix_changed = false;
-
-    // Select col and wait for col selecton to stabilize
-    select_col(current_col);
-    wait_us(30);
-
-    // For each row...
-    for(uint8_t row_index = 0; row_index < ROWS_PER_HAND; row_index++)
-    {
-
-        // Store last value of row prior to reading
-        matrix_row_t last_row_value = current_matrix[row_index];
-
-        // Check row pin state
-        if ((_SFR_IO8(row_pins[row_index] >> 4) & _BV(row_pins[row_index] & 0xF)) == 0)
-        {
-            // Pin LO, set col bit
-            current_matrix[row_index] |= (ROW_SHIFTER << current_col);
-        }
-        else
-        {
-            // Pin HI, clear col bit
-            current_matrix[row_index] &= ~(ROW_SHIFTER << current_col);
-        }
-
-        // Determine if the matrix changed state
-        if ((last_row_value != current_matrix[row_index]) && !(matrix_changed))
-        {
-            matrix_changed = true;
-        }
-    }
-
-    // Unselect col
-    unselect_col(current_col);
-
-    return matrix_changed;
-}
-
-static void select_col(uint8_t col)
-{
-    uint8_t pin = col_pins[col];
-    _SFR_IO8((pin >> 4) + 1) |=  _BV(pin & 0xF); // OUT
-    _SFR_IO8((pin >> 4) + 2) &= ~_BV(pin & 0xF); // LOW
-}
-
-static void unselect_col(uint8_t col)
-{
-    uint8_t pin = col_pins[col];
-    _SFR_IO8((pin >> 4) + 1) &= ~_BV(pin & 0xF); // IN
-    _SFR_IO8((pin >> 4) + 2) |=  _BV(pin & 0xF); // HI
-}
-
-static void unselect_cols(void)
-{
-    for(uint8_t x = 0; x < MATRIX_COLS; x++) {
-        uint8_t pin = col_pins[x];
-        _SFR_IO8((pin >> 4) + 1) &= ~_BV(pin & 0xF); // IN
-        _SFR_IO8((pin >> 4) + 2) |=  _BV(pin & 0xF); // HI
-    }
-}
-
-#endif
diff --git a/keyboards/lets_split/rev1/config.h b/keyboards/lets_split/rev1/config.h
index c0e4d1fbc..a8d614915 100644
--- a/keyboards/lets_split/rev1/config.h
+++ b/keyboards/lets_split/rev1/config.h
@@ -16,10 +16,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef REV1_CONFIG_H
-#define REV1_CONFIG_H
-
-#include "config_common.h"
+#pragma once
 
 /* USB Device descriptor parameter */
 #define VENDOR_ID       0xFEED
@@ -80,5 +77,3 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_ONESHOT
 //#define NO_ACTION_MACRO
 //#define NO_ACTION_FUNCTION
-
-#endif
diff --git a/keyboards/lets_split/rev1/rev1.h b/keyboards/lets_split/rev1/rev1.h
index 073d83ef3..a43d4a25b 100644
--- a/keyboards/lets_split/rev1/rev1.h
+++ b/keyboards/lets_split/rev1/rev1.h
@@ -1,5 +1,4 @@
-#ifndef REV1_H
-#define REV1_H
+#pragma once
 
 #include "lets_split.h"
 
@@ -26,5 +25,3 @@
 	}
 
 #define LAYOUT_ortho_4x12 LAYOUT
-
-#endif
diff --git a/keyboards/lets_split/rev2/config.h b/keyboards/lets_split/rev2/config.h
index 1ff25cd48..8844e5bb8 100644
--- a/keyboards/lets_split/rev2/config.h
+++ b/keyboards/lets_split/rev2/config.h
@@ -16,10 +16,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef REV2_CONFIG_H
-#define REV2_CONFIG_H
-
-#include "config_common.h"
+#pragma once
 
 /* USB Device descriptor parameter */
 #define VENDOR_ID       0xFEED
@@ -80,6 +77,3 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_ONESHOT
 //#define NO_ACTION_MACRO
 //#define NO_ACTION_FUNCTION
-
-
-#endif
diff --git a/keyboards/lets_split/rev2/rev2.h b/keyboards/lets_split/rev2/rev2.h
index bf25ee856..34e64e89f 100644
--- a/keyboards/lets_split/rev2/rev2.h
+++ b/keyboards/lets_split/rev2/rev2.h
@@ -1,5 +1,4 @@
-#ifndef REV2_H
-#define REV2_H
+#pragma once
 
 #include "lets_split.h"
 
@@ -58,5 +57,3 @@
 #endif
 
 #define LAYOUT_ortho_4x12 LAYOUT
-
-#endif
diff --git a/keyboards/lets_split/rules.mk b/keyboards/lets_split/rules.mk
index 4cd972786..f9d1a0dad 100644
--- a/keyboards/lets_split/rules.mk
+++ b/keyboards/lets_split/rules.mk
@@ -1,11 +1,4 @@
-SRC += matrix.c \
-	   i2c.c \
-	   split_util.c \
-	   serial.c \
-	   ssd1306.c
-
 # MCU name
-#MCU = at90usb1287
 MCU = atmega32u4
 
 # Processor frequency.
@@ -42,7 +35,7 @@ F_USB = $(F_CPU)
 
 # Bootloader
 #     This definition is optional, and if your keyboard supports multiple bootloaders of
-#     different sizes, comment this out, and the correct address will be loaded 
+#     different sizes, comment this out, and the correct address will be loaded
 #     automatically (+60). See bootloader.mk for all options.
 BOOTLOADER = caterina
 
@@ -64,13 +57,12 @@ MIDI_ENABLE = no            # MIDI controls
 AUDIO_ENABLE = no           # Audio output on port C6
 UNICODE_ENABLE = no         # Unicode
 BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
-RGBLIGHT_ENABLE = no       # Enable WS2812 RGB underlight. 
-SUBPROJECT_rev1 = yes
-USE_I2C = yes
+RGBLIGHT_ENABLE = no       # Enable WS2812 RGB underlight.
+
 # Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
 SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 
-CUSTOM_MATRIX = yes
+SPLIT_KEYBOARD = yes
 
 LAYOUTS = ortho_4x12
 
diff --git a/keyboards/lets_split/serial.c b/keyboards/lets_split/serial.c
deleted file mode 100644
index 74bcbb6bf..000000000
--- a/keyboards/lets_split/serial.c
+++ /dev/null
@@ -1,228 +0,0 @@
-/*
- * WARNING: be careful changing this code, it is very timing dependent
- */
-
-#ifndef F_CPU
-#define F_CPU 16000000
-#endif
-
-#include <avr/io.h>
-#include <avr/interrupt.h>
-#include <util/delay.h>
-#include <stdbool.h>
-#include "serial.h"
-
-#ifndef USE_I2C
-
-// Serial pulse period in microseconds. Its probably a bad idea to lower this
-// value.
-#define SERIAL_DELAY 24
-
-uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0};
-uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0};
-
-#define SLAVE_DATA_CORRUPT (1<<0)
-volatile uint8_t status = 0;
-
-inline static
-void serial_delay(void) {
-  _delay_us(SERIAL_DELAY);
-}
-
-inline static
-void serial_output(void) {
-  SERIAL_PIN_DDR |= SERIAL_PIN_MASK;
-}
-
-// make the serial pin an input with pull-up resistor
-inline static
-void serial_input(void) {
-  SERIAL_PIN_DDR  &= ~SERIAL_PIN_MASK;
-  SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
-}
-
-inline static
-uint8_t serial_read_pin(void) {
-  return !!(SERIAL_PIN_INPUT & SERIAL_PIN_MASK);
-}
-
-inline static
-void serial_low(void) {
-  SERIAL_PIN_PORT &= ~SERIAL_PIN_MASK;
-}
-
-inline static
-void serial_high(void) {
-  SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
-}
-
-void serial_master_init(void) {
-  serial_output();
-  serial_high();
-}
-
-void serial_slave_init(void) {
-  serial_input();
-
-  // Enable INT0
-  EIMSK |= _BV(INT0);
-  // Trigger on falling edge of INT0
-  EICRA &= ~(_BV(ISC00) | _BV(ISC01));
-}
-
-// Used by the master to synchronize timing with the slave.
-static
-void sync_recv(void) {
-  serial_input();
-  // This shouldn't hang if the slave disconnects because the
-  // serial line will float to high if the slave does disconnect.
-  while (!serial_read_pin());
-  serial_delay();
-}
-
-// Used by the slave to send a synchronization signal to the master.
-static
-void sync_send(void) {
-  serial_output();
-
-  serial_low();
-  serial_delay();
-
-  serial_high();
-}
-
-// Reads a byte from the serial line
-static
-uint8_t serial_read_byte(void) {
-  uint8_t byte = 0;
-  serial_input();
-  for ( uint8_t i = 0; i < 8; ++i) {
-    byte = (byte << 1) | serial_read_pin();
-    serial_delay();
-    _delay_us(1);
-  }
-
-  return byte;
-}
-
-// Sends a byte with MSB ordering
-static
-void serial_write_byte(uint8_t data) {
-  uint8_t b = 8;
-  serial_output();
-  while( b-- ) {
-    if(data & (1 << b)) {
-      serial_high();
-    } else {
-      serial_low();
-    }
-    serial_delay();
-  }
-}
-
-// interrupt handle to be used by the slave device
-ISR(SERIAL_PIN_INTERRUPT) {
-  sync_send();
-
-  uint8_t checksum = 0;
-  for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {
-    serial_write_byte(serial_slave_buffer[i]);
-    sync_send();
-    checksum += serial_slave_buffer[i];
-  }
-  serial_write_byte(checksum);
-  sync_send();
-
-  // wait for the sync to finish sending
-  serial_delay();
-
-  // read the middle of pulses
-  _delay_us(SERIAL_DELAY/2);
-
-  uint8_t checksum_computed = 0;
-  for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {
-    serial_master_buffer[i] = serial_read_byte();
-    sync_send();
-    checksum_computed += serial_master_buffer[i];
-  }
-  uint8_t checksum_received = serial_read_byte();
-  sync_send();
-
-  serial_input(); // end transaction
-
-  if ( checksum_computed != checksum_received ) {
-    status |= SLAVE_DATA_CORRUPT;
-  } else {
-    status &= ~SLAVE_DATA_CORRUPT;
-  }
-}
-
-inline
-bool serial_slave_DATA_CORRUPT(void) {
-  return status & SLAVE_DATA_CORRUPT;
-}
-
-// Copies the serial_slave_buffer to the master and sends the
-// serial_master_buffer to the slave.
-//
-// Returns:
-// 0 => no error
-// 1 => slave did not respond
-int serial_update_buffers(void) {
-  // this code is very time dependent, so we need to disable interrupts
-  cli();
-
-  // signal to the slave that we want to start a transaction
-  serial_output();
-  serial_low();
-  _delay_us(1);
-
-  // wait for the slaves response
-  serial_input();
-  serial_high();
-  _delay_us(SERIAL_DELAY);
-
-  // check if the slave is present
-  if (serial_read_pin()) {
-    // slave failed to pull the line low, assume not present
-    sei();
-    return 1;
-  }
-
-  // if the slave is present syncronize with it
-  sync_recv();
-
-  uint8_t checksum_computed = 0;
-  // receive data from the slave
-  for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {
-    serial_slave_buffer[i] = serial_read_byte();
-    sync_recv();
-    checksum_computed += serial_slave_buffer[i];
-  }
-  uint8_t checksum_received = serial_read_byte();
-  sync_recv();
-
-  if (checksum_computed != checksum_received) {
-    sei();
-    return 1;
-  }
-
-  uint8_t checksum = 0;
-  // send data to the slave
-  for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {
-    serial_write_byte(serial_master_buffer[i]);
-    sync_recv();
-    checksum += serial_master_buffer[i];
-  }
-  serial_write_byte(checksum);
-  sync_recv();
-
-  // always, release the line when not in use
-  serial_output();
-  serial_high();
-
-  sei();
-  return 0;
-}
-
-#endif
diff --git a/keyboards/lets_split/serial.h b/keyboards/lets_split/serial.h
deleted file mode 100644
index 15fe4db7b..000000000
--- a/keyboards/lets_split/serial.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#ifndef MY_SERIAL_H
-#define MY_SERIAL_H
-
-#include "config.h"
-#include <stdbool.h>
-
-/* TODO:  some defines for interrupt setup */
-#define SERIAL_PIN_DDR DDRD
-#define SERIAL_PIN_PORT PORTD
-#define SERIAL_PIN_INPUT PIND
-#define SERIAL_PIN_MASK _BV(PD0)
-#define SERIAL_PIN_INTERRUPT INT0_vect
-
-#define SERIAL_SLAVE_BUFFER_LENGTH MATRIX_ROWS/2
-#define SERIAL_MASTER_BUFFER_LENGTH 1
-
-// Buffers for master - slave communication
-extern volatile uint8_t serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH];
-extern volatile uint8_t serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH];
-
-void serial_master_init(void);
-void serial_slave_init(void);
-int serial_update_buffers(void);
-bool serial_slave_data_corrupt(void);
-
-#endif
diff --git a/keyboards/lets_split/sockets/config.h b/keyboards/lets_split/sockets/config.h
index a45cdd13b..10d0c997e 100644
--- a/keyboards/lets_split/sockets/config.h
+++ b/keyboards/lets_split/sockets/config.h
@@ -16,10 +16,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef SOCKETS_CONFIG_H
-#define SOCKETS_CONFIG_H
-
-#include "config_common.h"
+#pragma once
 
 /* USB Device descriptor parameter */
 #define VENDOR_ID       0xBEE5
@@ -85,6 +82,3 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_ONESHOT
 //#define NO_ACTION_MACRO
 //#define NO_ACTION_FUNCTION
-
-
-#endif
diff --git a/keyboards/lets_split/sockets/sockets.h b/keyboards/lets_split/sockets/sockets.h
index bd1019263..a79770bac 100644
--- a/keyboards/lets_split/sockets/sockets.h
+++ b/keyboards/lets_split/sockets/sockets.h
@@ -1,5 +1,4 @@
-#ifndef SOCKETS_H
-#define SOCKETS_H
+#pragma once
 #define DISABLE_JTAG // The keyboard uses PF4 and PF7, which are used by JTAG.
 
 #include "lets_split.h"
@@ -59,5 +58,3 @@
 #endif
 
 #define LAYOUT_ortho_4x12 LAYOUT
-
-#endif
diff --git a/keyboards/lets_split/split_util.c b/keyboards/lets_split/split_util.c
deleted file mode 100644
index 346cbc908..000000000
--- a/keyboards/lets_split/split_util.c
+++ /dev/null
@@ -1,86 +0,0 @@
-#include <avr/io.h>
-#include <avr/wdt.h>
-#include <avr/power.h>
-#include <avr/interrupt.h>
-#include <util/delay.h>
-#include <avr/eeprom.h>
-#include "split_util.h"
-#include "matrix.h"
-#include "keyboard.h"
-#include "config.h"
-#include "timer.h"
-
-#ifdef USE_I2C
-#  include "i2c.h"
-#else
-#  include "serial.h"
-#endif
-
-volatile bool isLeftHand = true;
-
-static void setup_handedness(void) {
-  #ifdef EE_HANDS
-    isLeftHand = eeprom_read_byte(EECONFIG_HANDEDNESS);
-  #else
-    // I2C_MASTER_RIGHT is deprecated, use MASTER_RIGHT instead, since this works for both serial and i2c
-    #if defined(I2C_MASTER_RIGHT) || defined(MASTER_RIGHT)
-      isLeftHand = !has_usb();
-    #else
-      isLeftHand = has_usb();
-    #endif
-  #endif
-}
-
-static void keyboard_master_setup(void) {
-#ifdef USE_I2C
-    i2c_master_init();
-#ifdef SSD1306OLED
-    matrix_master_OLED_init ();
-#endif
-#else
-    serial_master_init();
-#endif
-}
-
-static void keyboard_slave_setup(void) {
-  timer_init();
-#ifdef USE_I2C
-    i2c_slave_init(SLAVE_I2C_ADDRESS);
-#else
-    serial_slave_init();
-#endif
-}
-
-bool has_usb(void) {
-   USBCON |= (1 << OTGPADE); //enables VBUS pad
-   _delay_us(5);
-   return (USBSTA & (1<<VBUS));  //checks state of VBUS
-}
-
-void split_keyboard_setup(void) {
-   setup_handedness();
-
-   if (has_usb()) {
-      keyboard_master_setup();
-   } else {
-      keyboard_slave_setup();
-   }
-   sei();
-}
-
-void keyboard_slave_loop(void) {
-   matrix_init();
-
-   while (1) {
-      matrix_slave_scan();
-   }
-}
-
-// this code runs before the usb and keyboard is initialized
-void matrix_setup(void) {
-    split_keyboard_setup();
-
-    if (!has_usb()) {
-        keyboard_slave_loop();
-    }
-}
diff --git a/keyboards/lets_split/split_util.h b/keyboards/lets_split/split_util.h
deleted file mode 100644
index 595a0659e..000000000
--- a/keyboards/lets_split/split_util.h
+++ /dev/null
@@ -1,20 +0,0 @@
-#ifndef SPLIT_KEYBOARD_UTIL_H
-#define SPLIT_KEYBOARD_UTIL_H
-
-#include <stdbool.h>
-#include "eeconfig.h"
-
-#define SLAVE_I2C_ADDRESS           0x32
-
-extern volatile bool isLeftHand;
-
-// slave version of matix scan, defined in matrix.c
-void matrix_slave_scan(void);
-
-void split_keyboard_setup(void);
-bool has_usb(void);
-void keyboard_slave_loop(void);
-
-void matrix_master_OLED_init (void);
-
-#endif