2021 February 27 Breaking Changes Update (#12040)

14 files changed, 620 insertions, 128 deletions

diff --git a/drivers/apa102/apa102.c b/drivers/apa102/apa102.c
new file mode 100644
index 0000000000..7396dc3c55
--- /dev/null
+++ b/drivers/apa102/apa102.c
@@ -0,0 +1,151 @@
+/* Copyright 2020 Aldehir Rojas
+ * Copyright 2017 Mikkel (Duckle29)
+ *
+ * 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/>.
+ */
+
+#include "apa102.h"
+#include "quantum.h"
+
+#ifndef APA102_NOPS
+#    if defined(__AVR__)
+#        define APA102_NOPS 0  // AVR at 16 MHz already spends 62.5 ns per clock, so no extra delay is needed
+#    elif defined(PROTOCOL_CHIBIOS)
+
+#        include "hal.h"
+#        if defined(STM32F0XX) || defined(STM32F1XX) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32L0XX)
+#            define APA102_NOPS (100 / (1000000000L / (STM32_SYSCLK / 4)))  // This calculates how many loops of 4 nops to run to delay 100 ns
+#        else
+#            error("APA102_NOPS configuration required")
+#            define APA102_NOPS 0  // this just pleases the compile so the above error is easier to spot
+#        endif
+#    endif
+#endif
+
+#define io_wait                                 \
+    do {                                        \
+        for (int i = 0; i < APA102_NOPS; i++) { \
+            __asm__ volatile("nop\n\t"          \
+                             "nop\n\t"          \
+                             "nop\n\t"          \
+                             "nop\n\t");        \
+        }                                       \
+    } while (0)
+
+#define APA102_SEND_BIT(byte, bit)               \
+    do {                                         \
+        writePin(RGB_DI_PIN, (byte >> bit) & 1); \
+        io_wait;                                 \
+        writePinHigh(RGB_CI_PIN);                \
+        io_wait;                                 \
+        writePinLow(RGB_CI_PIN);                 \
+        io_wait;                                 \
+    } while (0)
+
+uint8_t apa102_led_brightness = APA102_DEFAULT_BRIGHTNESS;
+
+void static apa102_start_frame(void);
+void static apa102_end_frame(uint16_t num_leds);
+
+void static apa102_send_frame(uint8_t red, uint8_t green, uint8_t blue, uint8_t brightness);
+void static apa102_send_byte(uint8_t byte);
+
+void apa102_setleds(LED_TYPE *start_led, uint16_t num_leds) {
+    LED_TYPE *end = start_led + num_leds;
+
+    apa102_start_frame();
+    for (LED_TYPE *led = start_led; led < end; led++) {
+        apa102_send_frame(led->r, led->g, led->b, apa102_led_brightness);
+    }
+    apa102_end_frame(num_leds);
+}
+
+// Overwrite the default rgblight_call_driver to use apa102 driver
+void rgblight_call_driver(LED_TYPE *start_led, uint8_t num_leds) { apa102_setleds(start_led, num_leds); }
+
+void static apa102_init(void) {
+    setPinOutput(RGB_DI_PIN);
+    setPinOutput(RGB_CI_PIN);
+
+    writePinLow(RGB_DI_PIN);
+    writePinLow(RGB_CI_PIN);
+}
+
+void apa102_set_brightness(uint8_t brightness) {
+    if (brightness > APA102_MAX_BRIGHTNESS) {
+        apa102_led_brightness = APA102_MAX_BRIGHTNESS;
+    } else if (brightness < 0) {
+        apa102_led_brightness = 0;
+    } else {
+        apa102_led_brightness = brightness;
+    }
+}
+
+void static apa102_send_frame(uint8_t red, uint8_t green, uint8_t blue, uint8_t brightness) {
+    apa102_send_byte(0b11100000 | brightness);
+    apa102_send_byte(blue);
+    apa102_send_byte(green);
+    apa102_send_byte(red);
+}
+
+void static apa102_start_frame(void) {
+    apa102_init();
+    for (uint16_t i = 0; i < 4; i++) {
+        apa102_send_byte(0);
+    }
+}
+
+void static apa102_end_frame(uint16_t num_leds) {
+    // This function has been taken from: https://github.com/pololu/apa102-arduino/blob/master/APA102.h
+    // and adapted. The code is MIT licensed. I think thats compatible?
+    //
+    // The data stream seen by the last LED in the chain will be delayed by
+    // (count - 1) clock edges, because each LED before it inverts the clock
+    // line and delays the data by one clock edge.  Therefore, to make sure
+    // the last LED actually receives the data we wrote, the number of extra
+    // edges we send at the end of the frame must be at least (count - 1).
+    //
+    // Assuming we only want to send these edges in groups of size K, the
+    // C/C++ expression for the minimum number of groups to send is:
+    //
+    //   ((count - 1) + (K - 1)) / K
+    //
+    // The C/C++ expression above is just (count - 1) divided by K,
+    // rounded up to the nearest whole number if there is a remainder.
+    //
+    // We set K to 16 and use the formula above as the number of frame-end
+    // bytes to transfer.  Each byte has 16 clock edges.
+    //
+    // We are ignoring the specification for the end frame in the APA102
+    // datasheet, which says to send 0xFF four times, because it does not work
+    // when you have 66 LEDs or more, and also it results in unwanted white
+    // pixels if you try to update fewer LEDs than are on your LED strip.
+    uint16_t iterations = (num_leds + 14) / 16;
+    for (uint16_t i = 0; i < iterations; i++) {
+        apa102_send_byte(0);
+    }
+
+    apa102_init();
+}
+
+void static apa102_send_byte(uint8_t byte) {
+    APA102_SEND_BIT(byte, 7);
+    APA102_SEND_BIT(byte, 6);
+    APA102_SEND_BIT(byte, 5);
+    APA102_SEND_BIT(byte, 4);
+    APA102_SEND_BIT(byte, 3);
+    APA102_SEND_BIT(byte, 2);
+    APA102_SEND_BIT(byte, 1);
+    APA102_SEND_BIT(byte, 0);
+}
diff --git a/drivers/avr/apa102.h b/drivers/apa102/apa102.h
index d4c1e18ee1..58cf020c1e 100644
--- a/drivers/avr/apa102.h
+++ b/drivers/apa102/apa102.h
@@ -1,10 +1,5 @@
-/*
- * light weight WS2812 lib include
- *
- * Version 2.3  - Nev 29th 2015
- * Author: Tim (cpldcpu@gmail.com)
- *
- * Please do not change this file! All configuration is handled in "ws2812_config.h"
+/* Copyright 2020 Aldehir Rojas
+ * Copyright 2017 Mikkel (Duckle29)
  *
  * 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
@@ -22,24 +17,25 @@
 
 #pragma once
 
-#include <avr/io.h>
-#include <avr/interrupt.h>
-
 #include "color.h"
 
+#ifndef APA102_DEFAULT_BRIGHTNESS
+#    define APA102_DEFAULT_BRIGHTNESS 31
+#endif
+
+#define APA102_MAX_BRIGHTNESS 31
+
+extern uint8_t apa102_led_brightness;
+
 /* User Interface
  *
  * Input:
- *         ledarray:           An array of GRB data describing the LED colors
- *         number_of_leds:     The number of LEDs to write
- *         pinmask (optional): Bitmask describing the output bin. e.g. _BV(PB0)
+ *         start_led:          An array of GRB data describing the LED colors
+ *         num_leds:           The number of LEDs to write
  *
  * The functions will perform the following actions:
  *         - Set the data-out pin as output
  *         - Send out the LED data
- *         - Wait 50�s to reset the LEDs
  */
-
-void apa102_setleds(LED_TYPE *ledarray, uint16_t number_of_leds);
-void apa102_setleds_pin(LED_TYPE *ledarray, uint16_t number_of_leds, uint8_t pinmask);
-void apa102_setleds_rgbw(LED_TYPE *ledarray, uint16_t number_of_leds);
+void apa102_setleds(LED_TYPE *start_led, uint16_t num_leds);
+void apa102_set_brightness(uint8_t brightness);
diff --git a/drivers/avr/apa102.c b/drivers/avr/apa102.c
deleted file mode 100644
index 740acb5739..0000000000
--- a/drivers/avr/apa102.c
+++ /dev/null
@@ -1,96 +0,0 @@
-/*
- * APA102 lib V1.0a
- *
- * Controls APA102 RGB-LEDs
- * Author: Mikkel (Duckle29 on GitHub)
- *
- * Dec 22th, 2017  v1.0a Initial Version
- *
- * 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/>.
- */
-
-#include "apa102.h"
-#include <avr/interrupt.h>
-#include <avr/io.h>
-#include <util/delay.h>
-#include "debug.h"
-
-// Setleds for standard RGB
-void inline apa102_setleds(LED_TYPE *ledarray, uint16_t leds) { apa102_setleds_pin(ledarray, leds, _BV(RGB_DI_PIN & 0xF), _BV(RGB_CLK_PIN & 0xF)); }
-
-void static inline apa102_setleds_pin(LED_TYPE *ledarray, uint16_t leds, uint8_t pinmask_DI, uint8_t pinmask_CLK) {
-    setPinOutput(RGB_DI_PIN);
-    setPinOutput(RGB_CLK_PIN);
-
-    apa102_send_array((uint8_t *)ledarray, leds)
-}
-
-void apa102_send_array(uint8_t *data, uint16_t leds) {  // Data is struct of 3 bytes. RGB - leds is number of leds in data
-    apa102_start_frame();
-    while (leds--) {
-        apa102_send_frame(0xFF000000 | (data->b << 16) | (data->g << 8) | data->r);
-        data++;
-    }
-    apa102_end_frame(leds);
-}
-
-void apa102_send_frame(uint32_t frame) {
-    for (uint32_t i = 0xFF; i > 0;) {
-        apa102_send_byte(frame & i);
-        i = i << 8;
-    }
-}
-
-void apa102_start_frame() { apa102_send_frame(0); }
-
-void apa102_end_frame(uint16_t leds) {
-    // This function has been taken from: https://github.com/pololu/apa102-arduino/blob/master/APA102.h
-    // and adapted. The code is MIT licensed. I think thats compatible?
-
-    // We need to send some more bytes to ensure that all the LEDs in the
-    // chain see their new color and start displaying it.
-    //
-    // The data stream seen by the last LED in the chain will be delayed by
-    // (count - 1) clock edges, because each LED before it inverts the clock
-    // line and delays the data by one clock edge.  Therefore, to make sure
-    // the last LED actually receives the data we wrote, the number of extra
-    // edges we send at the end of the frame must be at least (count - 1).
-    // For the APA102C, that is sufficient.
-    //
-    // The SK9822 only updates after it sees 32 zero bits followed by one more
-    // rising edge.  To avoid having the update time depend on the color of
-    // the last LED, we send a dummy 0xFF byte.  (Unfortunately, this means
-    // that partial updates of the beginning of an LED strip are not possible;
-    // the LED after the last one you are trying to update will be black.)
-    // After that, to ensure that the last LED in the chain sees 32 zero bits
-    // and a rising edge, we need to send at least 65 + (count - 1) edges.  It
-    // is sufficent and simpler to just send (5 + count/16) bytes of zeros.
-    //
-    // We are ignoring the specification for the end frame in the APA102/SK9822
-    // datasheets because it does not actually ensure that all the LEDs will
-    // start displaying their new colors right away.
-
-    apa102_send_byte(0xFF);
-    for (uint16_t i = 0; i < 5 + leds / 16; i++) {
-        apa102_send_byte(0);
-    }
-}
-
-void apa102_send_byte(uint8_t byte) {
-    uint8_t i;
-    for (i = 0; i < 8; i++) {
-        writePin(RGB_DI_PIN, !!(byte & (1 << (7 - i))));
-        writePinHigh(RGB_CLK_PIN);
-    }
-}
diff --git a/drivers/avr/serial.c b/drivers/avr/serial.c
index 526a0946b2..3647bee0d3 100644
--- a/drivers/avr/serial.c
+++ b/drivers/avr/serial.c
@@ -20,7 +20,7 @@
 
 #ifdef SOFT_SERIAL_PIN
 
-#    if !(defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
+#    if !(defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB162__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
 #        error serial.c is not supported for the currently selected MCU
 #    endif
 // if using ATmega32U4/2, AT90USBxxx I2C, can not use PD0 and PD1 in soft serial.
@@ -52,8 +52,8 @@
 #        define EICRx EICRA
 #    endif
 
-// ATmegaxxU2 specific config
-#    if defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__)
+// ATmegaxxU2/AT90USB162 specific config
+#    if defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_AT90USB162__)
 // PD4(INT5), PD6(INT6), PD7(INT7), PC7(INT4)
 #        if SOFT_SERIAL_PIN == D4
 #            define EIMSK_BIT _BV(INT5)
diff --git a/drivers/avr/spi_master.c b/drivers/avr/spi_master.c
index cbec9f36e1..19ca0ced44 100644
--- a/drivers/avr/spi_master.c
+++ b/drivers/avr/spi_master.c
@@ -20,7 +20,7 @@
 #include "quantum.h"
 #include "timer.h"
 
-#if defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
+#if defined(__AVR_AT90USB162__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
 #    define SPI_SCK_PIN B1
 #    define SPI_MOSI_PIN B2
 #    define SPI_MISO_PIN B3
diff --git a/drivers/avr/spi_master.h b/drivers/avr/spi_master.h
index e36a7c21c0..9203698dd5 100644
--- a/drivers/avr/spi_master.h
+++ b/drivers/avr/spi_master.h
@@ -21,7 +21,7 @@
 typedef int16_t spi_status_t;
 
 // Hardware SS pin is defined in the header so that user code can refer to it
-#if defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
+#if defined(__AVR_AT90USB162__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
 #    define SPI_SS_PIN B0
 #elif defined(__AVR_ATmega32A__)
 #    define SPI_SS_PIN B4
diff --git a/drivers/avr/uart.c b/drivers/avr/uart.c
new file mode 100644
index 0000000000..c6abcb6fe0
--- /dev/null
+++ b/drivers/avr/uart.c
@@ -0,0 +1,170 @@
+/* UART Example for Teensy USB Development Board
+ * http://www.pjrc.com/teensy/
+ * Copyright (c) 2009 PJRC.COM, LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+// Version 1.0: Initial Release
+// Version 1.1: Add support for Teensy 2.0, minor optimizations
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#include "uart.h"
+
+#if defined(__AVR_AT90USB162__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
+#    define UDRn UDR1
+#    define UBRRnL UBRR1L
+#    define UCSRnA UCSR1A
+#    define UCSRnB UCSR1B
+#    define UCSRnC UCSR1C
+#    define U2Xn U2X1
+#    define RXENn RXEN1
+#    define TXENn TXEN1
+#    define RXCIEn RXCIE1
+#    define UCSZn1 UCSZ11
+#    define UCSZn0 UCSZ10
+#    define UDRIEn UDRIE1
+#    define USARTn_UDRE_vect USART1_UDRE_vect
+#    define USARTn_RX_vect USART1_RX_vect
+#elif defined(__AVR_ATmega32A__)
+#    define UDRn UDR
+#    define UBRRnL UBRRL
+#    define UCSRnA UCSRA
+#    define UCSRnB UCSRB
+#    define UCSRnC UCSRC
+#    define U2Xn U2X
+#    define RXENn RXEN
+#    define TXENn TXEN
+#    define RXCIEn RXCIE
+#    define UCSZn1 UCSZ1
+#    define UCSZn0 UCSZ0
+#    define UDRIEn UDRIE
+#    define USARTn_UDRE_vect USART_UDRE_vect
+#    define USARTn_RX_vect USART_RX_vect
+#elif defined(__AVR_ATmega328__) || defined(__AVR_ATmega328P__)
+#    define UDRn UDR0
+#    define UBRRnL UBRR0L
+#    define UCSRnA UCSR0A
+#    define UCSRnB UCSR0B
+#    define UCSRnC UCSR0C
+#    define U2Xn U2X0
+#    define RXENn RXEN0
+#    define TXENn TXEN0
+#    define RXCIEn RXCIE0
+#    define UCSZn1 UCSZ01
+#    define UCSZn0 UCSZ00
+#    define UDRIEn UDRIE0
+#    define USARTn_UDRE_vect USART_UDRE_vect
+#    define USARTn_RX_vect USART_RX_vect
+#endif
+
+// These buffers may be any size from 2 to 256 bytes.
+#define RX_BUFFER_SIZE 64
+#define TX_BUFFER_SIZE 256
+
+static volatile uint8_t tx_buffer[TX_BUFFER_SIZE];
+static volatile uint8_t tx_buffer_head;
+static volatile uint8_t tx_buffer_tail;
+static volatile uint8_t rx_buffer[RX_BUFFER_SIZE];
+static volatile uint8_t rx_buffer_head;
+static volatile uint8_t rx_buffer_tail;
+
+// Initialize the UART
+void uart_init(uint32_t baud) {
+    cli();
+    UBRRnL         = (F_CPU / 4 / baud - 1) / 2;
+    UCSRnA         = (1 << U2Xn);
+    UCSRnB         = (1 << RXENn) | (1 << TXENn) | (1 << RXCIEn);
+    UCSRnC         = (1 << UCSZn1) | (1 << UCSZn0);
+    tx_buffer_head = tx_buffer_tail = 0;
+    rx_buffer_head = rx_buffer_tail = 0;
+    sei();
+}
+
+// Transmit a byte
+void uart_putchar(uint8_t c) {
+    uint8_t i;
+
+    i = tx_buffer_head + 1;
+    if (i >= TX_BUFFER_SIZE) i = 0;
+    // return immediately to avoid deadlock when interrupt is disabled(called from ISR)
+    if (tx_buffer_tail == i && (SREG & (1 << SREG_I)) == 0) return;
+    while (tx_buffer_tail == i)
+        ;  // wait until space in buffer
+    // cli();
+    tx_buffer[i]   = c;
+    tx_buffer_head = i;
+    UCSRnB         = (1 << RXENn) | (1 << TXENn) | (1 << RXCIEn) | (1 << UDRIEn);
+    // sei();
+}
+
+// Receive a byte
+uint8_t uart_getchar(void) {
+    uint8_t c, i;
+
+    while (rx_buffer_head == rx_buffer_tail)
+        ;  // wait for character
+    i = rx_buffer_tail + 1;
+    if (i >= RX_BUFFER_SIZE) i = 0;
+    c              = rx_buffer[i];
+    rx_buffer_tail = i;
+    return c;
+}
+
+// Return whether the number of bytes waiting in the receive buffer is nonzero.
+// Call this before uart_getchar() to check if it will need
+// to wait for a byte to arrive.
+bool uart_available(void) {
+    uint8_t head, tail;
+
+    head = rx_buffer_head;
+    tail = rx_buffer_tail;
+    if (head >= tail) return (head - tail) > 0;
+    return (RX_BUFFER_SIZE + head - tail) > 0;
+}
+
+// Transmit Interrupt
+ISR(USARTn_UDRE_vect) {
+    uint8_t i;
+
+    if (tx_buffer_head == tx_buffer_tail) {
+        // buffer is empty, disable transmit interrupt
+        UCSRnB = (1 << RXENn) | (1 << TXENn) | (1 << RXCIEn);
+    } else {
+        i = tx_buffer_tail + 1;
+        if (i >= TX_BUFFER_SIZE) i = 0;
+        UDRn           = tx_buffer[i];
+        tx_buffer_tail = i;
+    }
+}
+
+// Receive Interrupt
+ISR(USARTn_RX_vect) {
+    uint8_t c, i;
+
+    c = UDRn;
+    i = rx_buffer_head + 1;
+    if (i >= RX_BUFFER_SIZE) i = 0;
+    if (i != rx_buffer_tail) {
+        rx_buffer[i]   = c;
+        rx_buffer_head = i;
+    }
+}
diff --git a/drivers/avr/uart.h b/drivers/avr/uart.h
new file mode 100644
index 0000000000..602eb3d8b0
--- /dev/null
+++ b/drivers/avr/uart.h
@@ -0,0 +1,35 @@
+/* UART Example for Teensy USB Development Board
+ * http://www.pjrc.com/teensy/
+ * Copyright (c) 2009 PJRC.COM, LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+void uart_init(uint32_t baud);
+
+void uart_putchar(uint8_t c);
+
+uint8_t uart_getchar(void);
+
+bool uart_available(void);
diff --git a/drivers/chibios/serial_usart.c b/drivers/chibios/serial_usart.c
index a3e21f90bc..7c81b16464 100644
--- a/drivers/chibios/serial_usart.c
+++ b/drivers/chibios/serial_usart.c
@@ -58,7 +58,10 @@
 #    error invalid SELECT_SOFT_SERIAL_SPEED value
 #endif
 
-#define TIMEOUT 100
+#ifndef SERIAL_USART_TIMEOUT
+#    define SERIAL_USART_TIMEOUT 100
+#endif
+
 #define HANDSHAKE_MAGIC 7
 
 static inline msg_t sdWriteHalfDuplex(SerialDriver* driver, uint8_t* data, uint8_t size) {
@@ -201,21 +204,21 @@ int soft_serial_transaction(int index) {
     sdClear(&SERIAL_USART_DRIVER);
 
     // First chunk is always transaction id
-    sdWriteTimeout(&SERIAL_USART_DRIVER, &sstd_index, sizeof(sstd_index), TIME_MS2I(TIMEOUT));
+    sdWriteTimeout(&SERIAL_USART_DRIVER, &sstd_index, sizeof(sstd_index), TIME_MS2I(SERIAL_USART_TIMEOUT));
 
     uint8_t sstd_index_shake = 0xFF;
 
     // Which we always read back first so that we can error out correctly
     //   - due to the half duplex limitations on return codes, we always have to read *something*
     //   - without the read, write only transactions *always* succeed, even during the boot process where the slave is not ready
-    res = sdReadTimeout(&SERIAL_USART_DRIVER, &sstd_index_shake, sizeof(sstd_index_shake), TIME_MS2I(TIMEOUT));
+    res = sdReadTimeout(&SERIAL_USART_DRIVER, &sstd_index_shake, sizeof(sstd_index_shake), TIME_MS2I(SERIAL_USART_TIMEOUT));
     if (res < 0 || (sstd_index_shake != (sstd_index ^ HANDSHAKE_MAGIC))) {
         dprintf("serial::usart_shake NO_RESPONSE\n");
         return TRANSACTION_NO_RESPONSE;
     }
 
     if (trans->initiator2target_buffer_size) {
-        res = sdWriteTimeout(&SERIAL_USART_DRIVER, trans->initiator2target_buffer, trans->initiator2target_buffer_size, TIME_MS2I(TIMEOUT));
+        res = sdWriteTimeout(&SERIAL_USART_DRIVER, trans->initiator2target_buffer, trans->initiator2target_buffer_size, TIME_MS2I(SERIAL_USART_TIMEOUT));
         if (res < 0) {
             dprintf("serial::usart_transmit NO_RESPONSE\n");
             return TRANSACTION_NO_RESPONSE;
@@ -223,7 +226,7 @@ int soft_serial_transaction(int index) {
     }
 
     if (trans->target2initiator_buffer_size) {
-        res = sdReadTimeout(&SERIAL_USART_DRIVER, trans->target2initiator_buffer, trans->target2initiator_buffer_size, TIME_MS2I(TIMEOUT));
+        res = sdReadTimeout(&SERIAL_USART_DRIVER, trans->target2initiator_buffer, trans->target2initiator_buffer_size, TIME_MS2I(SERIAL_USART_TIMEOUT));
         if (res < 0) {
             dprintf("serial::usart_receive NO_RESPONSE\n");
             return TRANSACTION_NO_RESPONSE;
diff --git a/drivers/chibios/uart.c b/drivers/chibios/uart.c
new file mode 100644
index 0000000000..030335b342
--- /dev/null
+++ b/drivers/chibios/uart.c
@@ -0,0 +1,50 @@
+/* Copyright 2021
+ *
+ *  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/>.
+ */
+
+#include "uart.h"
+
+#include "quantum.h"
+
+static SerialConfig serialConfig = {SERIAL_DEFAULT_BITRATE, SD1_CR1, SD1_CR2, SD1_CR3};
+
+void uart_init(uint32_t baud) {
+    static bool is_initialised = false;
+
+    if (!is_initialised) {
+        is_initialised = true;
+
+        serialConfig.speed = baud;
+
+#if defined(USE_GPIOV1)
+        palSetLineMode(SD1_TX_PIN, PAL_MODE_STM32_ALTERNATE_OPENDRAIN);
+        palSetLineMode(SD1_RX_PIN, PAL_MODE_STM32_ALTERNATE_OPENDRAIN);
+#else
+        palSetLineMode(SD1_TX_PIN, PAL_MODE_ALTERNATE(SD1_TX_PAL_MODE) | PAL_STM32_OTYPE_OPENDRAIN);
+        palSetLineMode(SD1_RX_PIN, PAL_MODE_ALTERNATE(SD1_RX_PAL_MODE) | PAL_STM32_OTYPE_OPENDRAIN);
+#endif
+        sdStart(&SERIAL_DRIVER, &serialConfig);
+    }
+}
+
+void uart_putchar(uint8_t c) { sdPut(&SERIAL_DRIVER, c); }
+
+uint8_t uart_getchar(void) {
+    msg_t res = sdGet(&SERIAL_DRIVER);
+
+    return (uint8_t)res;
+}
+
+bool uart_available(void) { return !sdGetWouldBlock(&SERIAL_DRIVER); }
diff --git a/drivers/chibios/uart.h b/drivers/chibios/uart.h
new file mode 100644
index 0000000000..b4e20e9fd3
--- /dev/null
+++ b/drivers/chibios/uart.h
@@ -0,0 +1,77 @@
+/* Copyright 2021
+ *
+ *  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/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#include <hal.h>
+
+#ifndef SERIAL_DRIVER
+#    define SERIAL_DRIVER SD1
+#endif
+
+#ifndef SD1_TX_PIN
+#    define SD1_TX_PIN A9
+#endif
+
+#ifndef SD1_TX_PAL_MODE
+#    define SD1_TX_PAL_MODE 7
+#endif
+
+#ifndef SD1_RX_PIN
+#    define SD1_RX_PIN A10
+#endif
+
+#ifndef SD1_RX_PAL_MODE
+#    define SD1_RX_PAL_MODE 7
+#endif
+
+#ifndef SD1_CTS_PIN
+#    define SD1_CTS_PIN A11
+#endif
+
+#ifndef SD1_CTS_PAL_MODE
+#    define SD1_CTS_PAL_MODE 7
+#endif
+
+#ifndef SD1_RTS_PIN
+#    define SD1_RTS_PIN A12
+#endif
+
+#ifndef SD1_RTS_PAL_MODE
+#    define SD1_RTS_PAL_MODE 7
+#endif
+
+#ifndef SD1_CR1
+#    define SD1_CR1 0
+#endif
+
+#ifndef SD1_CR2
+#    define SD1_CR2 0
+#endif
+
+#ifndef SD1_CR3
+#    define SD1_CR3 0
+#endif
+
+void uart_init(uint32_t baud);
+
+void uart_putchar(uint8_t c);
+
+uint8_t uart_getchar(void);
+
+bool uart_available(void);
diff --git a/drivers/chibios/usbpd_stm32g4.c b/drivers/chibios/usbpd_stm32g4.c
new file mode 100644
index 0000000000..f16ca8aeae
--- /dev/null
+++ b/drivers/chibios/usbpd_stm32g4.c
@@ -0,0 +1,76 @@
+/* Copyright 2021 Nick Brassel (@tzarc)
+ *
+ * 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/>.
+ */
+
+#include <quantum.h>
+
+#ifndef USBPD_UCPD1_CFG1
+#    define USBPD_UCPD1_CFG1 (UCPD_CFG1_PSC_UCPDCLK_0 | UCPD_CFG1_TRANSWIN_3 | UCPD_CFG1_IFRGAP_4 | UCPD_CFG1_HBITCLKDIV_4)
+#endif  // USBPD_UCPD1_CFG1
+
+// Initialises the USBPD subsystem
+__attribute__((weak)) void usbpd_init(void) {
+    // Disable dead-battery signals
+    PWR->CR3 |= PWR_CR3_UCPD_DBDIS;
+    // Enable the clock for the UCPD1 peripheral
+    RCC->APB1ENR2 |= RCC_APB1ENR2_UCPD1EN;
+
+    // Copy the existing value
+    uint32_t CFG1 = UCPD1->CFG1;
+    // Force-disable UCPD1 before configuring
+    CFG1 &= ~UCPD_CFG1_UCPDEN;
+    // Configure UCPD1
+    CFG1 = USBPD_UCPD1_CFG1;
+    // Apply the changes
+    UCPD1->CFG1 = CFG1;
+    // Enable UCPD1
+    UCPD1->CFG1 |= UCPD_CFG1_UCPDEN;
+
+    // Copy the existing value
+    uint32_t CR = UCPD1->CR;
+    // Clear out ANASUBMODE (irrelevant as a sink device)
+    CR &= ~UCPD_CR_ANASUBMODE_Msk;
+    // Advertise our capabilities as a sink, with both CC lines enabled
+    CR |= UCPD_CR_ANAMODE | UCPD_CR_CCENABLE_Msk;
+    // Apply the changes
+    UCPD1->CR = CR;
+}
+
+// Gets the current state of the USBPD allowance
+__attribute__((weak)) usbpd_allowance_t usbpd_get_allowance(void) {
+    uint32_t CR = UCPD1->CR;
+
+    int ucpd_enabled = (UCPD1->CFG1 & UCPD_CFG1_UCPDEN_Msk) >> UCPD_CFG1_UCPDEN_Pos;
+    int anamode      = (CR & UCPD_CR_ANAMODE_Msk) >> UCPD_CR_ANAMODE_Pos;
+    int cc_enabled   = (CR & UCPD_CR_CCENABLE_Msk) >> UCPD_CR_CCENABLE_Pos;
+
+    if (ucpd_enabled && anamode && cc_enabled) {
+        uint32_t SR         = UCPD1->SR;
+        int      vstate_cc1 = (SR & UCPD_SR_TYPEC_VSTATE_CC1_Msk) >> UCPD_SR_TYPEC_VSTATE_CC1_Pos;
+        int      vstate_cc2 = (SR & UCPD_SR_TYPEC_VSTATE_CC2_Msk) >> UCPD_SR_TYPEC_VSTATE_CC2_Pos;
+        int      vstate_max = vstate_cc1 > vstate_cc2 ? vstate_cc1 : vstate_cc2;
+        switch (vstate_max) {
+            case 0:
+            case 1:
+                return USBPD_500MA;  // Note that this is 500mA (i.e. max USB 2.0), not 900mA, as we're not using USB 3.1 as a sink device.
+            case 2:
+                return USBPD_1500MA;
+            case 3:
+                return USBPD_3000MA;
+        }
+    }
+
+    return USBPD_500MA;
+}
\ No newline at end of file
diff --git a/drivers/qwiic/qwiic.mk b/drivers/qwiic/qwiic.mk
index b23c25657d..164bd72108 100644
--- a/drivers/qwiic/qwiic.mk
+++ b/drivers/qwiic/qwiic.mk
@@ -1,16 +1,17 @@
-ifneq ($(strip $(QWIIC_ENABLE)),)
+ifeq ($(strip $(QWIIC_ENABLE)),yes)
   COMMON_VPATH += $(DRIVER_PATH)/qwiic
   OPT_DEFS += -DQWIIC_ENABLE
   SRC += qwiic.c
   QUANTUM_LIB_SRC += i2c_master.c
-endif
 
-ifneq ($(filter JOYSTIIC, $(QWIIC_ENABLE)),)
+ifneq ($(filter JOYSTIIC, $(QWIIC_DRIVERS)),)
   OPT_DEFS += -DQWIIC_JOYSTIIC_ENABLE
   SRC += joystiic.c
 endif
 
-ifneq ($(filter MICRO_OLED, $(QWIIC_ENABLE)),)
+ifneq ($(filter MICRO_OLED, $(QWIIC_DRIVERS)),)
   OPT_DEFS += -DQWIIC_MICRO_OLED_ENABLE
   SRC += micro_oled.c
 endif
+
+endif
diff --git a/drivers/usbpd.h b/drivers/usbpd.h
new file mode 100644
index 0000000000..df4f29bb9d
--- /dev/null
+++ b/drivers/usbpd.h
@@ -0,0 +1,29 @@
+/* Copyright 2021 Nick Brassel (@tzarc)
+ *
+ * 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/>.
+ */
+
+#pragma once
+
+typedef enum {
+    USBPD_500MA,
+    USBPD_1500MA,
+    USBPD_3000MA,
+} usbpd_allowance_t;
+
+// Initialises the USBPD subsystem
+void usbpd_init(void);
+
+// Gets the current state of the USBPD allowance
+usbpd_allowance_t usbpd_get_allowance(void);
\ No newline at end of file