Extensible split data sync (#11930)

* Extensible split data sync capability through transactions.

- Split common transport has been split up between the transport layer
  and data layer.
- Split "transactions" model used, with convergence between I2C and
  serial data definitions.
- Slave matrix "generation count" is used to determine if the full slave
  matrix needs to be retrieved.
- Encoders get the same "generation count" treatment.
- All other blocks of data are synchronised when a change is detected.
- All transmissions have a globally-configurable deadline before a
  transmission is forced (`FORCED_SYNC_THROTTLE_MS`, default 100ms).
- Added atomicity for all core-synced data, preventing partial updates
- Added retries to AVR i2c_master's i2c_start, to minimise the number of
  failed transactions when interrupts are disabled on the slave due to
  atomicity checks.
- Some keyboards have had slight modifications made in order to ensure
  that they still build due to firmware size restrictions.

* Fixup LED_MATRIX compile.

* Parameterise ERROR_DISCONNECT_COUNT.

6 files changed, 12 insertions, 4 deletions

diff --git a/keyboards/keebio/iris/rev2/rules.mk b/keyboards/keebio/iris/rev2/rules.mk
index 765fa7f07a..197bad4764 100644
--- a/keyboards/keebio/iris/rev2/rules.mk
+++ b/keyboards/keebio/iris/rev2/rules.mk
@@ -32,3 +32,5 @@ RGBLIGHT_ENABLE = yes       # Enable WS2812 RGB underlight.
 SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 
 SPLIT_KEYBOARD = yes
+
+LTO_ENABLE = yes
\ No newline at end of file
diff --git a/keyboards/keebio/iris/rev3/rules.mk b/keyboards/keebio/iris/rev3/rules.mk
index ea92bc98f5..b64eab5a4b 100644
--- a/keyboards/keebio/iris/rev3/rules.mk
+++ b/keyboards/keebio/iris/rev3/rules.mk
@@ -33,3 +33,4 @@ SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 
 SPLIT_KEYBOARD = yes
 ENCODER_ENABLE = yes
+LTO_ENABLE = yes
\ No newline at end of file
diff --git a/keyboards/keebio/iris/rev4/rules.mk b/keyboards/keebio/iris/rev4/rules.mk
index ea92bc98f5..9bf5688da0 100644
--- a/keyboards/keebio/iris/rev4/rules.mk
+++ b/keyboards/keebio/iris/rev4/rules.mk
@@ -33,3 +33,5 @@ SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 
 SPLIT_KEYBOARD = yes
 ENCODER_ENABLE = yes
+
+LTO_ENABLE = yes
\ No newline at end of file
diff --git a/keyboards/keebio/quefrency/rules.mk b/keyboards/keebio/quefrency/rules.mk
index 2c5ad0c36b..c674e10162 100644
--- a/keyboards/keebio/quefrency/rules.mk
+++ b/keyboards/keebio/quefrency/rules.mk
@@ -19,3 +19,4 @@ SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 SPLIT_KEYBOARD = yes
 
 DEFAULT_FOLDER = keebio/quefrency/rev1
+LTO_ENABLE = yes
diff --git a/keyboards/keebio/viterbi/rev2/rules.mk b/keyboards/keebio/viterbi/rev2/rules.mk
index f95e7ae6a4..829d6a56e0 100644
--- a/keyboards/keebio/viterbi/rev2/rules.mk
+++ b/keyboards/keebio/viterbi/rev2/rules.mk
@@ -1,3 +1,5 @@
 BACKLIGHT_ENABLE = yes
 
 LAYOUTS = ortho_5x14
+
+LTO_ENABLE = yes
\ No newline at end of file
diff --git a/keyboards/keebio/viterbi/rules.mk b/keyboards/keebio/viterbi/rules.mk
index 0b746d1720..92576d33e8 100644
--- a/keyboards/keebio/viterbi/rules.mk
+++ b/keyboards/keebio/viterbi/rules.mk
@@ -19,16 +19,16 @@ BOOTMAGIC_ENABLE = no       # Virtual DIP switch configuration
 MOUSEKEY_ENABLE = yes       # Mouse keys
 EXTRAKEY_ENABLE = yes       # Audio control and System control
 CONSOLE_ENABLE = no         # Console for debug
-COMMAND_ENABLE = yes        # Commands for debug and configuration
+COMMAND_ENABLE = no         # Commands for debug and configuration
 NKRO_ENABLE = no            # 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
+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 = no       # Enable WS2812 RGB underlight.
+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
+SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
 
 SPLIT_KEYBOARD = yes