6 files changed, 78 insertions, 18 deletions

diff --git a/docs/breaking_changes.md b/docs/breaking_changes.md
index 3e85a7076..2ad8b5a14 100644
--- a/docs/breaking_changes.md
+++ b/docs/breaking_changes.md
@@ -96,3 +96,7 @@ This happens immediately after the previous `develop` branch is merged.
     * [ ] Create a PR for `develop`
     * [ ] Make sure travis comes back clean
     * [ ] Merge `develop` PR
+
+## Post-merge operations
+
+* (Optional) [update ChibiOS + ChibiOS-Contrib on `develop`](chibios_upgrade_instructions.md)
\ No newline at end of file
diff --git a/docs/chibios_upgrade_instructions.md b/docs/chibios_upgrade_instructions.md
new file mode 100644
index 000000000..40c2faafc
--- /dev/null
+++ b/docs/chibios_upgrade_instructions.md
@@ -0,0 +1,56 @@
+# ChibiOS Upgrade Procedure
+
+ChibiOS and ChibiOS-Contrib need to be updated in tandem -- the latter has a branch tied to the ChibiOS version in use and should not be mixed with different versions.
+
+## Getting ChibiOS
+
+* `svn` Initialisation:
+    * Only needed to be done once
+    * You might need to separately install `git-svn` package in your OS's package manager
+    * `git svn init --stdlayout --prefix='svn/' http://svn.osdn.net/svnroot/chibios/`
+    * `git remote add qmk git@github.com:qmk/ChibiOS.git`
+* Updating:
+    * `git svn fetch`
+    * First time around this will take several hours
+    * Subsequent updates will be incremental only
+* Tagging example (work out which version first!):
+    * `git tag -a ver20.3.3 -m ver20.3.3 svn/tags/ver20.3.3`
+    * `git push qmk ver20.3.3`
+    * `git tag -a breaking_YYYY_qN -m breaking_YYYY_qN svn/tags/ver20.3.3`
+    * `git push qmk breaking_YYYY_qN`
+
+## Getting ChibiOS-Contrib
+
+* `git` Initialisation:
+    * `git clone git@github.com:qmk/ChibiOS-Contrib`
+    * `git remote add upstream https://github.com/ChibiOS/ChibiOS-Contrib`
+    * `git checkout -b chibios-20.3.x upstream/chibios-20.3.x`
+* Updating:
+    * `git fetch --all --tags --prune`
+    * `git checkout chibios-20.3.x`
+    * `git pull --ff-only`
+    * `git push origin chibios-20.3.x`
+    * `git tag -a breaking_YYYY_qN -m breaking_YYYY_qN chibios-20.3.x`
+    * `git push origin breaking_YYYY_qN`
+
+## Updating submodules
+
+* Update the submodules
+    * `cd $QMK_FIRMWARE`
+    * `git checkout develop`
+    * `git pull --ff-only`
+    * `git checkout -b chibios-version-bump`
+    * `cd lib/chibios`
+    * `git fetch --all --tags --prune`
+    * `git checkout breaking_YYYY_qN`
+    * `cd ../chibios-contrib`
+    * `git fetch --all --tags --prune`
+    * `git checkout breaking_YYYY_qN`
+* Build everything
+    * `cd $QMK_FIRMWARE`
+    * `qmk multibuild -j4`
+    * Make sure there are no errors
+* Push to the repo
+    * `git commit -am 'Update ChibiOS to XXXXXXXXX'`
+    * `git push --set-upstream origin chibios-version-bump`
+* Make a PR to qmk_firmware with the new branch
\ No newline at end of file
diff --git a/lib/chibios b/lib/chibios
-Subproject ffe54d63cb10a355add318f8e922e39f1c3d4bf
+Subproject 413e39c5681d181720440f2a8b7391f581788d7
diff --git a/lib/chibios-contrib b/lib/chibios-contrib
-Subproject 61baa6b036138c155f7cfc5646d833d9423f324
+Subproject 9c2bfa6aeba993345f5425d82807c101f8e25e6
diff --git a/quantum/matrix.c b/quantum/matrix.c
index 34d6af2e6..9298661ad 100644
--- a/quantum/matrix.c
+++ b/quantum/matrix.c
@@ -47,7 +47,7 @@ static inline void setPinInputHigh_atomic(pin_t pin) {
 
 #ifdef DIRECT_PINS
 
-static void init_pins(void) {
+__attribute__((weak)) void matrix_init_pins(void) {
     for (int row = 0; row < MATRIX_ROWS; row++) {
         for (int col = 0; col < MATRIX_COLS; col++) {
             pin_t pin = direct_pins[row][col];
@@ -58,7 +58,7 @@ static void init_pins(void) {
     }
 }
 
-static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
+__attribute__((weak)) bool matrix_read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
     // Start with a clear matrix row
     matrix_row_t current_row_value = 0;
 
@@ -90,14 +90,14 @@ static void unselect_rows(void) {
     }
 }
 
-static void init_pins(void) {
+__attribute__((weak)) void matrix_init_pins(void) {
     unselect_rows();
     for (uint8_t x = 0; x < MATRIX_COLS; x++) {
         setPinInputHigh_atomic(col_pins[x]);
     }
 }
 
-static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
+__attribute__((weak)) bool matrix_read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
     // Start with a clear matrix row
     matrix_row_t current_row_value = 0;
 
@@ -138,14 +138,14 @@ static void unselect_cols(void) {
     }
 }
 
-static void init_pins(void) {
+__attribute__((weak)) void matrix_init_pins(void) {
     unselect_cols();
     for (uint8_t x = 0; x < MATRIX_ROWS; x++) {
         setPinInputHigh_atomic(row_pins[x]);
     }
 }
 
-static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) {
+__attribute__((weak)) bool matrix_read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) {
     bool matrix_changed = false;
 
     // Select col
@@ -190,7 +190,7 @@ static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col)
 
 void matrix_init(void) {
     // initialize key pins
-    init_pins();
+    matrix_init_pins();
 
     // initialize matrix state: all keys off
     for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
@@ -209,12 +209,12 @@ uint8_t matrix_scan(void) {
 #if defined(DIRECT_PINS) || (DIODE_DIRECTION == COL2ROW)
     // Set row, read cols
     for (uint8_t current_row = 0; current_row < MATRIX_ROWS; current_row++) {
-        changed |= read_cols_on_row(raw_matrix, current_row);
+        changed |= matrix_read_cols_on_row(raw_matrix, current_row);
     }
 #elif (DIODE_DIRECTION == ROW2COL)
     // Set col, read rows
     for (uint8_t current_col = 0; current_col < MATRIX_COLS; current_col++) {
-        changed |= read_rows_on_col(raw_matrix, current_col);
+        changed |= matrix_read_rows_on_col(raw_matrix, current_col);
     }
 #endif
 
diff --git a/quantum/split_common/matrix.c b/quantum/split_common/matrix.c
index 039e7d977..a54ea90b3 100644
--- a/quantum/split_common/matrix.c
+++ b/quantum/split_common/matrix.c
@@ -61,7 +61,7 @@ static inline void setPinInputHigh_atomic(pin_t pin) {
 
 #ifdef DIRECT_PINS
 
-static void init_pins(void) {
+__attribute__((weak)) void matrix_init_pins(void) {
     for (int row = 0; row < MATRIX_ROWS; row++) {
         for (int col = 0; col < MATRIX_COLS; col++) {
             pin_t pin = direct_pins[row][col];
@@ -72,7 +72,7 @@ static void init_pins(void) {
     }
 }
 
-static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
+__attribute__((weak)) bool matrix_read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
     // Start with a clear matrix row
     matrix_row_t current_row_value = 0;
 
@@ -104,14 +104,14 @@ static void unselect_rows(void) {
     }
 }
 
-static void init_pins(void) {
+__attribute__((weak)) void matrix_init_pins(void) {
     unselect_rows();
     for (uint8_t x = 0; x < MATRIX_COLS; x++) {
         setPinInputHigh_atomic(col_pins[x]);
     }
 }
 
-static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
+__attribute__((weak)) bool matrix_read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
     // Start with a clear matrix row
     matrix_row_t current_row_value = 0;
 
@@ -152,14 +152,14 @@ static void unselect_cols(void) {
     }
 }
 
-static void init_pins(void) {
+__attribute__((weak)) void matrix_init_pins(void) {
     unselect_cols();
     for (uint8_t x = 0; x < ROWS_PER_HAND; x++) {
         setPinInputHigh_atomic(row_pins[x]);
     }
 }
 
-static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) {
+__attribute__((weak)) bool matrix_read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) {
     bool matrix_changed = false;
 
     // Select col
@@ -233,7 +233,7 @@ void matrix_init(void) {
     thatHand = ROWS_PER_HAND - thisHand;
 
     // initialize key pins
-    init_pins();
+    matrix_init_pins();
 
     // initialize matrix state: all keys off
     for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
@@ -293,12 +293,12 @@ uint8_t matrix_scan(void) {
 #if defined(DIRECT_PINS) || (DIODE_DIRECTION == COL2ROW)
     // Set row, read cols
     for (uint8_t current_row = 0; current_row < ROWS_PER_HAND; current_row++) {
-        local_changed |= read_cols_on_row(raw_matrix, current_row);
+        local_changed |= matrix_read_cols_on_row(raw_matrix, current_row);
     }
 #elif (DIODE_DIRECTION == ROW2COL)
     // Set col, read rows
     for (uint8_t current_col = 0; current_col < MATRIX_COLS; current_col++) {
-        local_changed |= read_rows_on_col(raw_matrix, current_col);
+        local_changed |= matrix_read_rows_on_col(raw_matrix, current_col);
     }
 #endif