Debounce refactor / API (#3720)

* Added xeal60 via clone of lets split

* Delete removed other keymaps

* Basic keymap (no FN). Compiles.

* Removed NP_STAR and NP_SLSH.

* Removed "debounce_algo = manual" in all keyboards with CUSTOM_MATRIX = yes.

* Changed order of rules in TMK. Documented feature.

* Fixed missing whitespace in debounce documentation

Table wasn't working due to missing newline.

* Added bold in a few areas.

* DO NOT USE - Removed debounce from TMK.

* Remove accidental xeal60 commit

* DO NOT USE - debounce successfully compiled.

* DO NOT USE Revert back to original API to support split_keyboards.

* Working eager_pk

* Whitespace cleanup.

* Restored debounce.h since there wasnt any real change.

* Moved debouncing_time variable  to inside #if debounce

* Removed check for custom_matrix. We can safely include the debounce file for compilation when custom_matrix is used.

* Removed #include "matrix.h" from debounce.h

* Bug fix - was using MATRIX_ROWS instead of num_rows

* Fixed compilation error with debounce_sym_g

* Renamed DEBOUNCE_ALGO to DEBOUNCE_TYPE

* Malloc array in debounce_eager_pk, since split keyboards only use MATRIX_ROWS/2.

* Fix compile error in debounce_eager_pk

* Stricter, leaner DEBOUNCE_TYPE section in common_features.mk. Cleanup debounce_type.mk

1 files changed, 28 insertions, 0 deletions

diff --git a/quantum/debounce/readme.md b/quantum/debounce/readme.md
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+Debounce algorithms belong in this folder.
+Here are a few ideas
+
+1) Global vs Per-Key vs Per-Row
+ * Global - one timer for all keys. Any key change state affects global timer
+ * Per key - one timer per key
+ * Per row - one timer per row
+
+2) Eager vs symmetric vs assymetric
+ * Eager - any key change is reported immediately. All further inputs for DEBOUNCE ms are ignored.
+ * Symmetric - wait for no changes for DEBOUNCE ms before reporting change
+ * Assymetric - wait for different times depending on key-down/key-up. E.g. Eager key-down, DEBOUNCE ms key up.
+
+3) Timestamp vs cycles
+ * old old old code waits n cycles, decreasing count by one each matrix_scan
+ * newer code stores the millisecond the change occurred, and does subraction to figure out time elapsed.
+ * Timestamps are superior, i don't think cycles will ever be used again once upgraded.
+
+The default algorithm is symmetric and global.
+Here are a few that could be implemented:
+
+debounce_sym_g.c
+debounce_sym_pk.c 
+debounce_sym_pr.c 
+debounce_sym_pr_cycles.c //currently used in ergo-dox
+debounce_eager_g.c
+debounce_eager_pk.c
+debounce_eager_pr.c //could be used in ergo-dox!