2021 May 29 Breaking Changes Update (#13034)

* Add Per Key functionality for AutoShift (#11536)

* LED Matrix: Reactive effect buffers & advanced indicators (#12588)

* [Keyboard] kint36: switch to sym_eager_pk debouncing (#12626)

* [Keyboard] kint2pp: reduce input latency by ≈10ms (#12625)

* LED Matrix: Split (#12633)

* [CI] Format code according to conventions (#12650)

* feat: infinite timeout for leader key (#6580)

* feat: implement leader_no_timeout logic

* docs(leader_key): infinite leader timeout docs

* Format code according to conventions (#12680)

* Update ADC driver for STM32F1xx, STM32F3xx, STM32F4xx (#12403)

* Fix default ADC_RESOLUTION for ADCv3 (and ADCv4)

Recent ChibiOS update removed ADC_CFGR1_RES_10BIT from the ADCv3 headers
(that macro should not have been there, because ADCv3 has CFGR instead of
CFGR1).  Fix the default value for ADC_RESOLUTION to use ADC_CFGR_RES_10BITS
if it is defined (that name is used for ADCv3 and ADCv4).

* Update ADC docs to match the actually used resolution

ADC driver for ChibiOS actually uses the 10-bit resolution by default
(probably to match AVR); fix the documentation accordingly.  Also add
both ADC_CFGR_RES_10BITS and ADC_CFGR1_RES_10BIT constants (these names
differ according to the ADC implementation in the particular MCU).

* Fix pinToMux() for B12 and B13 on STM32F3xx

Testing on STM32F303CCT6 revealed that the ADC mux values for B12 and
B13 pins were wrong.

* Add support for all possible analog pins on STM32F1xx

Added ADC mux values for pins A0...A7, B0, B1, C0...C5 on STM32F1xx
(they are the same at least for STM32F103x8 and larger F103 devices, and
also F102, F105, F107 families).  Actually tested on STM32F103C8T6
(therefore pins C0...C5 were not tested).

Pins F6...F10, which are present on STM32F103x[C-G] in 144-pin packages,
cannot be supported at the moment, because those pins are connected only
to ADC3, but the ChibiOS ADC driver for STM32F1xx supports only ADC1.

* Add support for all possible analog pins on STM32F4xx

Added ADC mux values for pins A0...A7, B0, B1, C0...C5 and optionally
F3...F10 (if STM32_ADC_USE_ADC3 is enabled).  These mux values are
apparently the same for all F4xx devices, except some smaller devices may
not have ADC3.

Actually tested on STM32F401CCU6, STM32F401CEU6, STM32F411CEU6 (using
various WeAct “Blackpill” boards); only pins A0...A7, B0, B1 were tested.

Pins F3...F10 are inside `#if STM32_ADC_USE_ADC3` because some devices
which don't have ADC3 also don't have the GPIOF port, therefore the code
which refers to Fx pins does not compile.

* Fix STM32F3xx ADC mux table in documentation

The ADC driver documentation had some errors in the mux table for STM32F3xx.
Fix this table to match the datasheet and the actual code (mux settings for
B12 and B13 were also tested on a real STM32F303CCT6 chip).

* Add STM32F1xx ADC pins to the documentation

* Add STM32F4xx ADC pins to the documentation

* Add initial support for tinyuf2 bootloader (when hosted on F411 blackpill) (#12600)

* Add support for jumping to tinyuf2 bootloader. Adds blackpill UF2 example.

* Update flashing.md

* Update chconf.h

* Update config.h

* Update halconf.h

* Update mcuconf.h

* eeprom driver: Refactor where eeprom driver initialisation (and EEPROM emulation initialisation) occurs to make it non-target-specific. (#12671)

* Add support for MCU = STM32F446 (#12619)

* Add support for MCU = STM32F446

* Update platforms/chibios/GENERIC_STM32_F446XE/configs/config.h

* Restore mcuconf.h to the one used by RT-STM32F446RE-NUCLEO64

* stm32f446: update mcuconf.h and board.h for 16MHz operation, with USB enabled, and other peripherals disabled.

* Format code according to conventions (#12682)

* Format code according to conventions (#12687)

* Add STM32L433 and L443 support (#12063)

* initial L433 commit

* change to XC

* fix L433

* disable all peripherals

* update system and peripheral clocks

* 433 change

* use its own board  files

* revert its own board files

* l433 specific change

* fix stm32l432xx define

* remove duplicate #define

* fix bootloader jump

* move to L443xx and add i2c2, spi2, usart3 to mcuconf.h

* move to L443

* move to L443

* fix sdmmc in mcuconf.h

* include STM32L443

* add L443

* Include L443 in compatible microcontrollers

* Include L443 in compatible microcontrollers

* Update config bootloader jump description

* Update ChibiOS define reasoning

* Update quantum/mcu_selection.mk

* fix git conflict

* Updated Function96 with V2 files and removed chconf.h and halconf.h (#12613)

* Fix bad PR merge for #6580. (#12721)

* Change RGB/LED Matrix to use a simple define for USB suspend (#12697)

* [CI] Format code according to conventions (#12731)

* Fixing transport's led/rgb matrix suspend state logic (#12770)

* [CI] Format code according to conventions (#12772)

* Fix comment parsing (#12750)

* Added OLED fade out support (#12086)

* fix some references to bin/qmk that slipped in (#12832)

* Resolve a number of warnings in `qmk generate-api` (#12833)

* New command: qmk console (#12828)

* stash poc

* stash

* tidy up implementation

* Tidy up slightly for review

* Tidy up slightly for review

* Bodge environment to make tests pass

* Refactor away from asyncio due to windows issues

* Filter devices

* align vid/pid printing

* Add hidapi to the installers

* start preparing for multiple hid_listeners

* udev rules for hid_listen

* refactor to move closer to end state

* very basic implementation of the threaded model

* refactor how vid/pid/index are supplied and parsed

* windows improvements

* read the report directly when usage page isn't available

* add per-device colors, the choice to show names or numbers, and refactor

* add timestamps

* Add support for showing bootloaders

* tweak the color for bootloaders

* Align bootloader disconnect with connect color

* add support for showing all bootloaders

* fix the pyusb check

* tweaks

* fix exception

* hide a stack trace behind -v

* add --no-bootloaders option

* add documentation for qmk console

* Apply suggestions from code review

* pyformat

* clean up and flesh out KNOWN_BOOTLOADERS

* Remove pointless SERIAL_LINK_ENABLE rules (#12846)

* Make Swap Hands use PROGMEM (#12284)

This converts the array that the Swap Hands feature uses to use PROGMEM,
and to read from that array, as such. Since this array never changes at
runtime, there is no reason to keep it in memory. Especially for AVR
boards, as memory is a precious resource.

* Fix another bin/qmk reference (#12856)

* [Keymap] Turn OLED off on suspend in soundmonster keymap (#10419)

* Fixup build errors on `develop` branch. (#12723)

* LED Matrix: Effects! (#12651)

* Fix syntax error when compiling for ARM (#12866)

* Remove KEYMAP and LAYOUT_kc (#12160)

* alias KEYMAP to LAYOUT

* remove KEYMAP and LAYOUT_kc

* Add setup, clone, and env to the list of commands we allow even with broken modules (#12868)

* Rename `point_t` -> `led_point_t` (#12864)

* [Keyboard] updated a vendor name / fixed minor keymap issues (#12881)

* Add missing LED Matrix suspend code to suspend.c (#12878)

* LED Matrix: Documentation (#12685)

* Deprecate `send_unicode_hex_string()` (#12602)

* Fix spelling mistake regarding LED Matrix in split_common. (#12888)

* [Keymap] Fix QWERTY/DVORAK status output for kzar keymap (#12895)

* Use milc.subcommand.config instead of qmk.cli.config (#12915)

* Use milc.subcommand.config instead

* pyformat

* remove the config test

* Add function to allow repeated blinking of one layer (#12237)

* Implement function rgblight_blink_layer_repeat to allow repeated blinking of one layer at a time

* Update doc

* Rework rgblight blinking according to requested change

* optimize storage

* Fixup housekeeping from being invoked twice per loop. (#12933)

* matrix: wait for row signal to go HIGH for every row (#12945)

I noticed this discrepancy (last row of the matrix treated differently than the
others) when optimizing the input latency of my keyboard controller, see also
https://michael.stapelberg.ch/posts/2021-05-08-keyboard-input-latency-qmk-kinesis/

Before this commit, when tuning the delays I noticed ghost key presses when
pressing the F2 key, which is on the last row of the keyboard matrix: the
dead_grave key, which is on the first row of the keyboard matrix, would be
incorrectly detected as pressed.

After this commit, all keyboard matrix rows are interpreted correctly.

I suspect that my setup is more susceptible to this nuance than others because I
use GPIO_INPUT_PIN_DELAY=0 and hence don’t have another delay that might mask
the problem.

* ensure we do not conflict with existing keymap aliases (#12976)

* Add support for up to 4 IS31FL3733 drivers (#12342)

* Convert Encoder callbacks to be boolean functions (#12805)

* [Keyboard] Fix Terrazzo build failure (#12977)

* Do not hard set config in CPTC files (#11864)

* [Keyboard] Corne - Remove legacy revision support (#12226)

* [Keymap] Update to Drashna keymap and user code (based on develop) (#12936)

* Add Full-duplex serial driver for ARM boards (#9842)

* Document LED_MATRIX_FRAMEBUFFER_EFFECTS (#12987)

* Backlight: add defines for default level and breathing state (#12560)

* Add dire message about LUFA mass storage bootloader (#13014)

* [Keyboard] Remove redundant legacy and common headers for crkbd (#13023)

Was causing compiler errors on some systems.

* Fix keyboards/keymaps for boolean encoder callback changes (#12985)

* `backlight.c`: include `eeprom.h` (#13024)

* Add changelog for 2021-05-29 Breaking Changes merge (#12939)

* Add ChangeLog for 2021-05-29 Breaking Changes Merge: initial version

* Add recent develop changes

* Sort recent develop changes

* Remove sections for ChibiOS changes per tzarc

No ChibiOS changes this round.

* Add and sort recent develop changes

* add notes about keyboard moves/deletions

* import changelog for PR 12172

Documents the change to BOOTMAGIC_ENABLE.

* update section headings

* re-sort changelog

* add additional note regarding Bootmagic changes

* remove changelog timestamp

* update dates in main Breaking Changes docs

* fix broken section anchors in previous changelogs

* add link to backlight/eeprom patch to changelog

* highlight some more changes

* link PRs from section headers

* Restore standard readme

* run: qmk cformat --core-only

9 files changed, 512 insertions, 66 deletions

diff --git a/drivers/chibios/analog.c b/drivers/chibios/analog.c
index 2b3872afbb..8c476fcac2 100644
--- a/drivers/chibios/analog.c
+++ b/drivers/chibios/analog.c
@@ -101,7 +101,11 @@
 
 // Options are 12, 10, 8, and 6 bit.
 #ifndef ADC_RESOLUTION
-#    define ADC_RESOLUTION ADC_CFGR1_RES_10BIT
+#    ifdef ADC_CFGR_RES_10BITS  // ADCv3, ADCv4
+#        define ADC_RESOLUTION ADC_CFGR_RES_10BITS
+#    else  // ADCv1, ADCv5, or the bodge for ADCv2 above
+#        define ADC_RESOLUTION ADC_CFGR1_RES_10BIT
+#    endif
 #endif
 
 static ADCConfig   adcCfg = {};
@@ -119,7 +123,7 @@ static ADCConversionGroup adcConversionGroup = {
     .smpr  = ADC_SAMPLING_RATE,
 #elif defined(USE_ADCV2)
 #    if !defined(STM32F1XX)
-    .cr2   = ADC_CR2_SWSTART,  // F103 seem very unhappy with, F401 seems very unhappy without...
+    .cr2 = ADC_CR2_SWSTART,  // F103 seem very unhappy with, F401 seems very unhappy without...
 #    endif
     .smpr2 = ADC_SMPR2_SMP_AN0(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN1(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN2(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN3(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN4(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN5(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN6(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN7(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN8(ADC_SAMPLING_RATE) | ADC_SMPR2_SMP_AN9(ADC_SAMPLING_RATE),
     .smpr1 = ADC_SMPR1_SMP_AN10(ADC_SAMPLING_RATE) | ADC_SMPR1_SMP_AN11(ADC_SAMPLING_RATE) | ADC_SMPR1_SMP_AN12(ADC_SAMPLING_RATE) | ADC_SMPR1_SMP_AN13(ADC_SAMPLING_RATE) | ADC_SMPR1_SMP_AN14(ADC_SAMPLING_RATE) | ADC_SMPR1_SMP_AN15(ADC_SAMPLING_RATE),
@@ -161,8 +165,8 @@ __attribute__((weak)) adc_mux pinToMux(pin_t pin) {
         case B0:  return TO_MUX( ADC_CHANNEL_IN12, 2 );
         case B1:  return TO_MUX( ADC_CHANNEL_IN1,  2 );
         case B2:  return TO_MUX( ADC_CHANNEL_IN12, 1 );
-        case B12: return TO_MUX( ADC_CHANNEL_IN2,  3 );
-        case B13: return TO_MUX( ADC_CHANNEL_IN3,  3 );
+        case B12: return TO_MUX( ADC_CHANNEL_IN3,  3 );
+        case B13: return TO_MUX( ADC_CHANNEL_IN5,  2 );
         case B14: return TO_MUX( ADC_CHANNEL_IN4,  3 );
         case B15: return TO_MUX( ADC_CHANNEL_IN5,  3 );
         case C0:  return TO_MUX( ADC_CHANNEL_IN6,  0 ); // Can also be ADC2
@@ -189,11 +193,52 @@ __attribute__((weak)) adc_mux pinToMux(pin_t pin) {
         case E15: return TO_MUX( ADC_CHANNEL_IN2,  3 );
         case F2:  return TO_MUX( ADC_CHANNEL_IN10, 0 ); // Can also be ADC2
         case F4:  return TO_MUX( ADC_CHANNEL_IN5,  0 );
-#elif defined(STM32F4XX) // TODO: add all pins
+#elif defined(STM32F4XX)
         case A0:  return TO_MUX( ADC_CHANNEL_IN0,  0 );
-        //case A1:  return TO_MUX( ADC_CHANNEL_IN1,  0 );
-#elif defined(STM32F1XX) // TODO: add all pins
+        case A1:  return TO_MUX( ADC_CHANNEL_IN1,  0 );
+        case A2:  return TO_MUX( ADC_CHANNEL_IN2,  0 );
+        case A3:  return TO_MUX( ADC_CHANNEL_IN3,  0 );
+        case A4:  return TO_MUX( ADC_CHANNEL_IN4,  0 );
+        case A5:  return TO_MUX( ADC_CHANNEL_IN5,  0 );
+        case A6:  return TO_MUX( ADC_CHANNEL_IN6,  0 );
+        case A7:  return TO_MUX( ADC_CHANNEL_IN7,  0 );
+        case B0:  return TO_MUX( ADC_CHANNEL_IN8,  0 );
+        case B1:  return TO_MUX( ADC_CHANNEL_IN9,  0 );
+        case C0:  return TO_MUX( ADC_CHANNEL_IN10, 0 );
+        case C1:  return TO_MUX( ADC_CHANNEL_IN11, 0 );
+        case C2:  return TO_MUX( ADC_CHANNEL_IN12, 0 );
+        case C3:  return TO_MUX( ADC_CHANNEL_IN13, 0 );
+        case C4:  return TO_MUX( ADC_CHANNEL_IN14, 0 );
+        case C5:  return TO_MUX( ADC_CHANNEL_IN15, 0 );
+#    if STM32_ADC_USE_ADC3
+        case F3:  return TO_MUX( ADC_CHANNEL_IN9,  2 );
+        case F4:  return TO_MUX( ADC_CHANNEL_IN14, 2 );
+        case F5:  return TO_MUX( ADC_CHANNEL_IN15, 2 );
+        case F6:  return TO_MUX( ADC_CHANNEL_IN4,  2 );
+        case F7:  return TO_MUX( ADC_CHANNEL_IN5,  2 );
+        case F8:  return TO_MUX( ADC_CHANNEL_IN6,  2 );
+        case F9:  return TO_MUX( ADC_CHANNEL_IN7,  2 );
+        case F10: return TO_MUX( ADC_CHANNEL_IN8,  2 );
+#    endif
+#elif defined(STM32F1XX)
         case A0:  return TO_MUX( ADC_CHANNEL_IN0,  0 );
+        case A1:  return TO_MUX( ADC_CHANNEL_IN1,  0 );
+        case A2:  return TO_MUX( ADC_CHANNEL_IN2,  0 );
+        case A3:  return TO_MUX( ADC_CHANNEL_IN3,  0 );
+        case A4:  return TO_MUX( ADC_CHANNEL_IN4,  0 );
+        case A5:  return TO_MUX( ADC_CHANNEL_IN5,  0 );
+        case A6:  return TO_MUX( ADC_CHANNEL_IN6,  0 );
+        case A7:  return TO_MUX( ADC_CHANNEL_IN7,  0 );
+        case B0:  return TO_MUX( ADC_CHANNEL_IN8,  0 );
+        case B1:  return TO_MUX( ADC_CHANNEL_IN9,  0 );
+        case C0:  return TO_MUX( ADC_CHANNEL_IN10, 0 );
+        case C1:  return TO_MUX( ADC_CHANNEL_IN11, 0 );
+        case C2:  return TO_MUX( ADC_CHANNEL_IN12, 0 );
+        case C3:  return TO_MUX( ADC_CHANNEL_IN13, 0 );
+        case C4:  return TO_MUX( ADC_CHANNEL_IN14, 0 );
+        case C5:  return TO_MUX( ADC_CHANNEL_IN15, 0 );
+        // STM32F103x[C-G] in 144-pin packages also have analog inputs on F6...F10, but they are on ADC3, and the
+        // ChibiOS ADC driver for STM32F1xx currently supports only ADC1, therefore these pins are not usable.
 #endif
     }
 
diff --git a/drivers/chibios/serial_usart.c b/drivers/chibios/serial_usart.c
index 7c81b16464..cae29388c3 100644
--- a/drivers/chibios/serial_usart.c
+++ b/drivers/chibios/serial_usart.c
@@ -1,13 +1,20 @@
-#include "quantum.h"
-#include "serial.h"
-#include "print.h"
-
-#include <ch.h>
-#include <hal.h>
+/* Copyright 2021 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 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 <http://www.gnu.org/licenses/>.
+ */
 
-#ifndef USART_CR1_M0
-#    define USART_CR1_M0 USART_CR1_M  // some platforms (f1xx) dont have this so
-#endif
+#include "serial_usart.h"
 
 #ifndef USE_GPIOV1
 // The default PAL alternate modes are used to signal that the pins are used for USART
@@ -20,50 +27,10 @@
 #    define SERIAL_USART_DRIVER SD1
 #endif
 
-#ifndef SERIAL_USART_CR1
-#    define SERIAL_USART_CR1 (USART_CR1_PCE | USART_CR1_PS | USART_CR1_M0)  // parity enable, odd parity, 9 bit length
-#endif
-
-#ifndef SERIAL_USART_CR2
-#    define SERIAL_USART_CR2 (USART_CR2_STOP_1)  // 2 stop bits
-#endif
-
-#ifndef SERIAL_USART_CR3
-#    define SERIAL_USART_CR3 0
-#endif
-
 #ifdef SOFT_SERIAL_PIN
 #    define SERIAL_USART_TX_PIN SOFT_SERIAL_PIN
 #endif
 
-#ifndef SELECT_SOFT_SERIAL_SPEED
-#    define SELECT_SOFT_SERIAL_SPEED 1
-#endif
-
-#ifdef SERIAL_USART_SPEED
-// Allow advanced users to directly set SERIAL_USART_SPEED
-#elif SELECT_SOFT_SERIAL_SPEED == 0
-#    define SERIAL_USART_SPEED 460800
-#elif SELECT_SOFT_SERIAL_SPEED == 1
-#    define SERIAL_USART_SPEED 230400
-#elif SELECT_SOFT_SERIAL_SPEED == 2
-#    define SERIAL_USART_SPEED 115200
-#elif SELECT_SOFT_SERIAL_SPEED == 3
-#    define SERIAL_USART_SPEED 57600
-#elif SELECT_SOFT_SERIAL_SPEED == 4
-#    define SERIAL_USART_SPEED 38400
-#elif SELECT_SOFT_SERIAL_SPEED == 5
-#    define SERIAL_USART_SPEED 19200
-#else
-#    error invalid SELECT_SOFT_SERIAL_SPEED value
-#endif
-
-#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) {
     msg_t ret = sdWrite(driver, data, size);
 
@@ -123,6 +90,10 @@ __attribute__((weak)) void usart_init(void) {
 #else
     palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_TX_PAL_MODE) | PAL_STM32_OTYPE_OPENDRAIN);
 #endif
+
+#if defined(USART_REMAP)
+    USART_REMAP;
+#endif
 }
 
 void usart_master_init(void) {
diff --git a/drivers/chibios/serial_usart.h b/drivers/chibios/serial_usart.h
new file mode 100644
index 0000000000..fee7b4d159
--- /dev/null
+++ b/drivers/chibios/serial_usart.h
@@ -0,0 +1,90 @@
+/* Copyright 2021 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 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 <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "quantum.h"
+#include "serial.h"
+#include "printf.h"
+
+#include <ch.h>
+#include <hal.h>
+
+#ifndef USART_CR1_M0
+#    define USART_CR1_M0 USART_CR1_M  // some platforms (f1xx) dont have this so
+#endif
+
+#ifndef SERIAL_USART_CR1
+#    define SERIAL_USART_CR1 (USART_CR1_PCE | USART_CR1_PS | USART_CR1_M0)  // parity enable, odd parity, 9 bit length
+#endif
+
+#ifndef SERIAL_USART_CR2
+#    define SERIAL_USART_CR2 (USART_CR2_STOP_1)  // 2 stop bits
+#endif
+
+#ifndef SERIAL_USART_CR3
+#    define SERIAL_USART_CR3 0
+#endif
+
+#if defined(USART1_REMAP)
+#    define USART_REMAP                             \
+        do {                                        \
+            (AFIO->MAPR |= AFIO_MAPR_USART1_REMAP); \
+        } while (0)
+#elif defined(USART2_REMAP)
+#    define USART_REMAP                             \
+        do {                                        \
+            (AFIO->MAPR |= AFIO_MAPR_USART2_REMAP); \
+        } while (0)
+#elif defined(USART3_PARTIALREMAP)
+#    define USART_REMAP                                          \
+        do {                                                     \
+            (AFIO->MAPR |= AFIO_MAPR_USART3_REMAP_PARTIALREMAP); \
+        } while (0)
+#elif defined(USART3_FULLREMAP)
+#    define USART_REMAP                                       \
+        do {                                                  \
+            (AFIO->MAPR |= AFIO_MAPR_USART3_REMAP_FULLREMAP); \
+        } while (0)
+#endif
+
+#ifndef SELECT_SOFT_SERIAL_SPEED
+#    define SELECT_SOFT_SERIAL_SPEED 1
+#endif
+
+#ifdef SERIAL_USART_SPEED
+// Allow advanced users to directly set SERIAL_USART_SPEED
+#elif SELECT_SOFT_SERIAL_SPEED == 0
+#    define SERIAL_USART_SPEED 460800
+#elif SELECT_SOFT_SERIAL_SPEED == 1
+#    define SERIAL_USART_SPEED 230400
+#elif SELECT_SOFT_SERIAL_SPEED == 2
+#    define SERIAL_USART_SPEED 115200
+#elif SELECT_SOFT_SERIAL_SPEED == 3
+#    define SERIAL_USART_SPEED 57600
+#elif SELECT_SOFT_SERIAL_SPEED == 4
+#    define SERIAL_USART_SPEED 38400
+#elif SELECT_SOFT_SERIAL_SPEED == 5
+#    define SERIAL_USART_SPEED 19200
+#else
+#    error invalid SELECT_SOFT_SERIAL_SPEED value
+#endif
+
+#ifndef SERIAL_USART_TIMEOUT
+#    define SERIAL_USART_TIMEOUT 100
+#endif
+
+#define HANDSHAKE_MAGIC 7
diff --git a/drivers/chibios/serial_usart_duplex.c b/drivers/chibios/serial_usart_duplex.c
new file mode 100644
index 0000000000..cc9b889ac2
--- /dev/null
+++ b/drivers/chibios/serial_usart_duplex.c
@@ -0,0 +1,261 @@
+/* Copyright 2021 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 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include "serial_usart.h"
+
+#include <stdatomic.h>
+
+#if !defined(USE_GPIOV1)
+// The default PAL alternate modes are used to signal that the pins are used for USART
+#    if !defined(SERIAL_USART_TX_PAL_MODE)
+#        define SERIAL_USART_TX_PAL_MODE 7
+#    endif
+#    if !defined(SERIAL_USART_RX_PAL_MODE)
+#        define SERIAL_USART_RX_PAL_MODE 7
+#    endif
+#endif
+
+#if !defined(SERIAL_USART_DRIVER)
+#    define SERIAL_USART_DRIVER UARTD1
+#endif
+
+#if !defined(SERIAL_USART_TX_PIN)
+#    define SERIAL_USART_TX_PIN A9
+#endif
+
+#if !defined(SERIAL_USART_RX_PIN)
+#    define SERIAL_USART_RX_PIN A10
+#endif
+
+#define SIGNAL_HANDSHAKE_RECEIVED 0x1
+
+void        handle_transactions_slave(uint8_t sstd_index);
+static void receive_transaction_handshake(UARTDriver* uartp, uint16_t received_handshake);
+
+/*
+ * UART driver configuration structure. We use the blocking DMA enabled API and
+ * the rxchar callback to receive handshake tokens but only on the slave halve.
+ */
+// clang-format off
+static UARTConfig uart_config = {
+    .txend1_cb = NULL,
+    .txend2_cb = NULL,
+    .rxend_cb = NULL,
+    .rxchar_cb = NULL,
+    .rxerr_cb = NULL,
+    .timeout_cb = NULL,
+    .speed = (SERIAL_USART_SPEED),
+    .cr1 = (SERIAL_USART_CR1),
+    .cr2 = (SERIAL_USART_CR2),
+    .cr3 = (SERIAL_USART_CR3)
+};
+// clang-format on
+
+static SSTD_t*              Transaction_table      = NULL;
+static uint8_t              Transaction_table_size = 0;
+static atomic_uint_least8_t handshake              = 0xFF;
+static thread_reference_t   tp_target              = NULL;
+
+/*
+ * This callback is invoked when a character is received but the application
+ * was not ready to receive it, the character is passed as parameter.
+ * Receive transaction table index from initiator, which doubles as basic handshake token. */
+static void receive_transaction_handshake(UARTDriver* uartp, uint16_t received_handshake) {
+    /* Check if received handshake is not a valid transaction id.
+     * Please note that we can still catch a seemingly valid handshake
+     * i.e. a byte from a ongoing transfer which is in the allowed range.
+     * So this check mainly prevents any obviously wrong handshakes and
+     * subsequent wakeups of the receiving thread, which is a costly operation. */
+    if (received_handshake > Transaction_table_size) {
+        return;
+    }
+
+    handshake = (uint8_t)received_handshake;
+    chSysLockFromISR();
+    /* Wakeup receiving thread to start a transaction. */
+    chEvtSignalI(tp_target, (eventmask_t)SIGNAL_HANDSHAKE_RECEIVED);
+    chSysUnlockFromISR();
+}
+
+__attribute__((weak)) void usart_init(void) {
+#if defined(USE_GPIOV1)
+    palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_STM32_ALTERNATE_PUSHPULL);
+    palSetLineMode(SERIAL_USART_RX_PIN, PAL_MODE_INPUT);
+#else
+    palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_TX_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_HIGHEST);
+    palSetLineMode(SERIAL_USART_RX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_RX_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_HIGHEST);
+#endif
+}
+
+/*
+ * This thread runs on the slave half and reacts to transactions initiated from the master.
+ */
+static THD_WORKING_AREA(waSlaveThread, 1024);
+static THD_FUNCTION(SlaveThread, arg) {
+    (void)arg;
+    chRegSetThreadName("slave_usart_tx_rx");
+
+    while (true) {
+        /* We sleep as long as there is no handshake waiting for us. */
+        chEvtWaitAny((eventmask_t)SIGNAL_HANDSHAKE_RECEIVED);
+        handle_transactions_slave(handshake);
+    }
+}
+
+void soft_serial_target_init(SSTD_t* const sstd_table, int sstd_table_size) {
+    Transaction_table      = sstd_table;
+    Transaction_table_size = (uint8_t)sstd_table_size;
+    usart_init();
+
+#if defined(USART_REMAP)
+    USART_REMAP;
+#endif
+
+    tp_target = chThdCreateStatic(waSlaveThread, sizeof(waSlaveThread), HIGHPRIO, SlaveThread, NULL);
+
+    // Start receiving handshake tokens on slave halve
+    uart_config.rxchar_cb = receive_transaction_handshake;
+    uartStart(&SERIAL_USART_DRIVER, &uart_config);
+}
+
+/**
+ * @brief React to transactions started by the master.
+ * This version uses duplex send and receive usart pheriphals and DMA backed transfers.
+ */
+void inline handle_transactions_slave(uint8_t sstd_index) {
+    size_t  buffer_size = 0;
+    msg_t   msg         = 0;
+    SSTD_t* trans       = &Transaction_table[sstd_index];
+
+    /* Send back the handshake which is XORed as a simple checksum,
+     to signal that the slave is ready to receive possible transaction buffers  */
+    sstd_index ^= HANDSHAKE_MAGIC;
+    buffer_size = (size_t)sizeof(sstd_index);
+    msg         = uartSendTimeout(&SERIAL_USART_DRIVER, &buffer_size, &sstd_index, TIME_MS2I(SERIAL_USART_TIMEOUT));
+
+    if (msg != MSG_OK) {
+        if (trans->status) {
+            *trans->status = TRANSACTION_NO_RESPONSE;
+        }
+        return;
+    }
+
+    /* Receive transaction buffer from the master. If this transaction requires it.*/
+    buffer_size = (size_t)trans->initiator2target_buffer_size;
+    if (buffer_size) {
+        msg = uartReceiveTimeout(&SERIAL_USART_DRIVER, &buffer_size, trans->initiator2target_buffer, TIME_MS2I(SERIAL_USART_TIMEOUT));
+        if (msg != MSG_OK) {
+            if (trans->status) {
+                *trans->status = TRANSACTION_NO_RESPONSE;
+            }
+            return;
+        }
+    }
+
+    /* Send transaction buffer to the master. If this transaction requires it. */
+    buffer_size = (size_t)trans->target2initiator_buffer_size;
+    if (buffer_size) {
+        msg = uartSendFullTimeout(&SERIAL_USART_DRIVER, &buffer_size, trans->target2initiator_buffer, TIME_MS2I(SERIAL_USART_TIMEOUT));
+        if (msg != MSG_OK) {
+            if (trans->status) {
+                *trans->status = TRANSACTION_NO_RESPONSE;
+            }
+            return;
+        }
+    }
+
+    if (trans->status) {
+        *trans->status = TRANSACTION_ACCEPTED;
+    }
+}
+
+void soft_serial_initiator_init(SSTD_t* const sstd_table, int sstd_table_size) {
+    Transaction_table      = sstd_table;
+    Transaction_table_size = (uint8_t)sstd_table_size;
+    usart_init();
+
+#if defined(SERIAL_USART_PIN_SWAP)
+    uart_config.cr2 |= USART_CR2_SWAP;  // master has swapped TX/RX pins
+#endif
+
+#if defined(USART_REMAP)
+    USART_REMAP;
+#endif
+
+    uartStart(&SERIAL_USART_DRIVER, &uart_config);
+}
+
+/**
+ * @brief Start transaction from the master to the slave.
+ * This version uses duplex send and receive usart pheriphals and DMA backed transfers.
+ *
+ * @param index Transaction Table index of the transaction to start.
+ * @return int TRANSACTION_NO_RESPONSE in case of Timeout.
+ *             TRANSACTION_TYPE_ERROR in case of invalid transaction index.
+ *             TRANSACTION_END in case of success.
+ */
+#if !defined(SERIAL_USE_MULTI_TRANSACTION)
+int soft_serial_transaction(void) {
+    uint8_t sstd_index = 0;
+#else
+int soft_serial_transaction(int index) {
+    uint8_t sstd_index = index;
+#endif
+
+    if (sstd_index > Transaction_table_size) {
+        return TRANSACTION_TYPE_ERROR;
+    }
+
+    SSTD_t* const trans       = &Transaction_table[sstd_index];
+    msg_t         msg         = 0;
+    size_t        buffer_size = (size_t)sizeof(sstd_index);
+
+    /* Send transaction table index to the slave, which doubles as basic handshake token. */
+    uartSendFullTimeout(&SERIAL_USART_DRIVER, &buffer_size, &sstd_index, TIME_MS2I(SERIAL_USART_TIMEOUT));
+
+    uint8_t sstd_index_shake = 0xFF;
+    buffer_size              = (size_t)sizeof(sstd_index_shake);
+
+    /* Receive the handshake token from the slave. The token was XORed by the slave as a simple checksum.
+     If the tokens match, the master will start to send and receive possible transaction buffers. */
+    msg = uartReceiveTimeout(&SERIAL_USART_DRIVER, &buffer_size, &sstd_index_shake, TIME_MS2I(SERIAL_USART_TIMEOUT));
+    if (msg != MSG_OK || (sstd_index_shake != (sstd_index ^ HANDSHAKE_MAGIC))) {
+        dprintln("USART: Handshake Failed");
+        return TRANSACTION_NO_RESPONSE;
+    }
+
+    /* Send transaction buffer to the slave. If this transaction requires it. */
+    buffer_size = (size_t)trans->initiator2target_buffer_size;
+    if (buffer_size) {
+        msg = uartSendFullTimeout(&SERIAL_USART_DRIVER, &buffer_size, trans->initiator2target_buffer, TIME_MS2I(SERIAL_USART_TIMEOUT));
+        if (msg != MSG_OK) {
+            dprintln("USART: Send Failed");
+            return TRANSACTION_NO_RESPONSE;
+        }
+    }
+
+    /* Receive transaction buffer from the slave. If this transaction requires it. */
+    buffer_size = (size_t)trans->target2initiator_buffer_size;
+    if (buffer_size) {
+        msg = uartReceiveTimeout(&SERIAL_USART_DRIVER, &buffer_size, trans->target2initiator_buffer, TIME_MS2I(SERIAL_USART_TIMEOUT));
+        if (msg != MSG_OK) {
+            dprintln("USART: Receive Failed");
+            return TRANSACTION_NO_RESPONSE;
+        }
+    }
+
+    return TRANSACTION_END;
+}
diff --git a/drivers/chibios/ws2812_pwm.c b/drivers/chibios/ws2812_pwm.c
index 140120d488..e6af55b6b3 100644
--- a/drivers/chibios/ws2812_pwm.c
+++ b/drivers/chibios/ws2812_pwm.c
@@ -27,6 +27,15 @@
 #    error "please consult your MCU's datasheet and specify in your config.h: #define WS2812_DMAMUX_ID STM32_DMAMUX1_TIM?_UP"
 #endif
 
+#ifndef WS2812_PWM_COMPLEMENTARY_OUTPUT
+#    define WS2812_PWM_OUTPUT_MODE PWM_OUTPUT_ACTIVE_HIGH
+#else
+#    if !STM32_PWM_USE_ADVANCED
+#        error "WS2812_PWM_COMPLEMENTARY_OUTPUT requires STM32_PWM_USE_ADVANCED == TRUE"
+#    endif
+#    define WS2812_PWM_OUTPUT_MODE PWM_COMPLEMENTARY_OUTPUT_ACTIVE_HIGH
+#endif
+
 // Push Pull or Open Drain Configuration
 // Default Push Pull
 #ifndef WS2812_EXTERNAL_PULLUP
@@ -247,7 +256,7 @@ void ws2812_init(void) {
         .channels =
             {
                 [0 ... 3]                = {.mode = PWM_OUTPUT_DISABLED, .callback = NULL},     // Channels default to disabled
-                [WS2812_PWM_CHANNEL - 1] = {.mode = PWM_OUTPUT_ACTIVE_HIGH, .callback = NULL},  // Turn on the channel we care about
+                [WS2812_PWM_CHANNEL - 1] = {.mode = WS2812_PWM_OUTPUT_MODE, .callback = NULL},  // Turn on the channel we care about
             },
         .cr2  = 0,
         .dier = TIM_DIER_UDE,  // DMA on update event for next period
diff --git a/drivers/chibios/ws2812_spi.c b/drivers/chibios/ws2812_spi.c
index 89df2987b5..e02cbabc02 100644
--- a/drivers/chibios/ws2812_spi.c
+++ b/drivers/chibios/ws2812_spi.c
@@ -32,6 +32,37 @@
 #    endif
 #endif
 
+// Define SPI config speed
+// baudrate should target 3.2MHz
+// F072 fpclk = 48MHz
+// 48/16 = 3Mhz
+#if WS2812_SPI_DIVISOR == 2
+#    define WS2812_SPI_DIVISOR (0)
+#elif WS2812_SPI_DIVISOR == 4
+#    define WS2812_SPI_DIVISOR (SPI_CR1_BR_0)
+#elif WS2812_SPI_DIVISOR == 8
+#    define WS2812_SPI_DIVISOR (SPI_CR1_BR_1)
+#elif WS2812_SPI_DIVISOR == 16  // same as default
+#    define WS2812_SPI_DIVISOR (SPI_CR1_BR_1 | SPI_CR1_BR_0)
+#elif WS2812_SPI_DIVISOR == 32
+#    define WS2812_SPI_DIVISOR (SPI_CR1_BR_2)
+#elif WS2812_SPI_DIVISOR == 64
+#    define WS2812_SPI_DIVISOR (SPI_CR1_BR_2 | SPI_CR1_BR_0)
+#elif WS2812_SPI_DIVISOR == 128
+#    define WS2812_SPI_DIVISOR (SPI_CR1_BR_2 | SPI_CR1_BR_1)
+#elif WS2812_SPI_DIVISOR == 256
+#    define WS2812_SPI_DIVISOR (SPI_CR1_BR_2 | SPI_CR1_BR_1 | SPI_CR1_BR_0)
+#else
+#    define WS2812_SPI_DIVISOR (SPI_CR1_BR_1 | SPI_CR1_BR_0)  // default
+#endif
+
+// Use SPI circular buffer
+#ifdef WS2812_SPI_USE_CIRCULAR_BUFFER
+#    define WS2812_SPI_BUFFER_MODE 1  // circular buffer
+#else
+#    define WS2812_SPI_BUFFER_MODE 0  // normal buffer
+#endif
+
 #define BYTES_FOR_LED_BYTE 4
 #define NB_COLORS 3
 #define BYTES_FOR_LED (BYTES_FOR_LED_BYTE * NB_COLORS)
@@ -81,14 +112,14 @@ void ws2812_init(void) {
     palSetLineMode(RGB_DI_PIN, WS2812_OUTPUT_MODE);
 
     // TODO: more dynamic baudrate
-    static const SPIConfig spicfg = {
-        0, NULL, PAL_PORT(RGB_DI_PIN), PAL_PAD(RGB_DI_PIN),
-        SPI_CR1_BR_1 | SPI_CR1_BR_0  // baudrate : fpclk / 8 => 1tick is 0.32us (2.25 MHz)
-    };
+    static const SPIConfig spicfg = {WS2812_SPI_BUFFER_MODE, NULL, PAL_PORT(RGB_DI_PIN), PAL_PAD(RGB_DI_PIN), WS2812_SPI_DIVISOR};
 
     spiAcquireBus(&WS2812_SPI);     /* Acquire ownership of the bus.    */
     spiStart(&WS2812_SPI, &spicfg); /* Setup transfer parameters.       */
     spiSelect(&WS2812_SPI);         /* Slave Select assertion.          */
+#ifdef WS2812_SPI_USE_CIRCULAR_BUFFER
+    spiStartSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
+#endif
 }
 
 void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) {
@@ -104,9 +135,11 @@ void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) {
 
     // Send async - each led takes ~0.03ms, 50 leds ~1.5ms, animations flushing faster than send will cause issues.
     // Instead spiSend can be used to send synchronously (or the thread logic can be added back).
-#ifdef WS2812_SPI_SYNC
+#ifndef WS2812_SPI_USE_CIRCULAR_BUFFER
+#    ifdef WS2812_SPI_SYNC
     spiSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
-#else
+#    else
     spiStartSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
+#    endif
 #endif
 }
diff --git a/drivers/issi/is31fl3733.c b/drivers/issi/is31fl3733.c
index dddf0cb734..d99e5339c9 100644
--- a/drivers/issi/is31fl3733.c
+++ b/drivers/issi/is31fl3733.c
@@ -68,7 +68,7 @@ uint8_t g_twi_transfer_buffer[20];
 uint8_t g_pwm_buffer[DRIVER_COUNT][192];
 bool    g_pwm_buffer_update_required[DRIVER_COUNT] = {false};
 
-uint8_t g_led_control_registers[DRIVER_COUNT][24]             = {{0}, {0}};
+uint8_t g_led_control_registers[DRIVER_COUNT][24]             = {0};
 bool    g_led_control_registers_update_required[DRIVER_COUNT] = {false};
 
 bool IS31FL3733_write_register(uint8_t addr, uint8_t reg, uint8_t data) {
diff --git a/drivers/oled/oled_driver.c b/drivers/oled/oled_driver.c
index 92c64399e2..082115d534 100644
--- a/drivers/oled/oled_driver.c
+++ b/drivers/oled/oled_driver.c
@@ -24,6 +24,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include "progmem.h"
 
+#include "keyboard.h"
+
 // Used commands from spec sheet: https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf
 // for SH1106: https://www.velleman.eu/downloads/29/infosheets/sh1106_datasheet.pdf
 
@@ -71,6 +73,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define PRE_CHARGE_PERIOD 0xD9
 #define VCOM_DETECT 0xDB
 
+// Advance Graphic Commands
+#define FADE_BLINK 0x23
+#define ENABLE_FADE 0x20
+#define ENABLE_BLINK 0x30
+
 // Charge Pump Commands
 #define CHARGE_PUMP 0x8D
 
@@ -152,6 +159,12 @@ static void InvertCharacter(uint8_t *cursor) {
 }
 
 bool oled_init(uint8_t rotation) {
+#if defined(USE_I2C) && defined(SPLIT_KEYBOARD)
+    if (!is_keyboard_master()) {
+        return true;
+    }
+#endif
+
     oled_rotation = oled_init_user(rotation);
     if (!HAS_FLAGS(oled_rotation, OLED_ROTATION_90)) {
         oled_rotation_width = OLED_DISPLAY_WIDTH;
@@ -539,7 +552,13 @@ bool oled_on(void) {
     oled_timeout = timer_read32() + OLED_TIMEOUT;
 #endif
 
-    static const uint8_t PROGMEM display_on[] = {I2C_CMD, DISPLAY_ON};
+    static const uint8_t PROGMEM display_on[] =
+#ifdef OLED_FADE_OUT
+        {I2C_CMD, FADE_BLINK, 0x00};
+#else
+        {I2C_CMD, DISPLAY_ON};
+#endif
+
     if (!oled_active) {
         if (I2C_TRANSMIT_P(display_on) != I2C_STATUS_SUCCESS) {
             print("oled_on cmd failed\n");
@@ -555,7 +574,13 @@ bool oled_off(void) {
         return !oled_active;
     }
 
-    static const uint8_t PROGMEM display_off[] = {I2C_CMD, DISPLAY_OFF};
+    static const uint8_t PROGMEM display_off[] =
+#ifdef OLED_FADE_OUT
+        {I2C_CMD, FADE_BLINK, ENABLE_FADE | OLED_FADE_OUT_INTERVAL};
+#else
+        {I2C_CMD, DISPLAY_OFF};
+#endif
+
     if (oled_active) {
         if (I2C_TRANSMIT_P(display_off) != I2C_STATUS_SUCCESS) {
             print("oled_off cmd failed\n");
diff --git a/drivers/oled/oled_driver.h b/drivers/oled/oled_driver.h
index 72ab21247d..cbf5380ee0 100644
--- a/drivers/oled/oled_driver.h
+++ b/drivers/oled/oled_driver.h
@@ -154,10 +154,22 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #    endif
 #endif
 
+#if !defined(OLED_FADE_OUT_INTERVAL)
+#    define OLED_FADE_OUT_INTERVAL 0x00
+#endif
+
+#if OLED_FADE_OUT_INTERVAL > 0x0F || OLED_FADE_OUT_INTERVAL < 0x00
+#    error OLED_FADE_OUT_INTERVAL must be between 0x00 and 0x0F
+#endif
+
 #if !defined(OLED_I2C_TIMEOUT)
 #    define OLED_I2C_TIMEOUT 100
 #endif
 
+#if !defined(OLED_UPDATE_INTERVAL) && defined(SPLIT_KEYBOARD)
+#    define OLED_UPDATE_INTERVAL 50
+#endif
+
 typedef struct __attribute__((__packed__)) {
     uint8_t *current_element;
     uint16_t remaining_element_count;