Fix up tap_code functionality (#4609)

* Add delay in Tap Code to avoid issues

I think a few people have reporting issues with it working properly, and it may be a timing issue.  The 'register_code' uses this sort of delay in some of the functions, and
this is probably why.

Adding the 100ms delay should hopefully fix any issues with it.

* Make tap_code delay configurable

* Update documentation

* Bring tap_code16 inline with changes

* Fix type for tap_code16

Bad copy-paste job

* Just use the value check for the define

* Clarify timing in docs

Co-Authored-By: drashna <drashna@live.com>

* Wordsmithing

Co-Authored-By: drashna <drashna@live.com>

6 files changed, 26 insertions, 2 deletions

diff --git a/docs/config_options.md b/docs/config_options.md
index b811fa877..69fecc8b4 100644
--- a/docs/config_options.md
+++ b/docs/config_options.md
@@ -160,6 +160,8 @@ If you define these options you will enable the associated feature, which may in
   * Set this to the number of combos that you're using in the [Combo](feature_combo.md) feature.
 * `#define COMBO_TERM 200`
   * how long for the Combo keys to be detected. Defaults to `TAPPING_TERM` if not defined.
+* `#define TAP_CODE_DELAY 100`
+  * Sets the delay between `register_code` and `unregister_code`, if you're having issues with it registering properly (common on VUSB boards). The value is in milliseconds.
 
 ## RGB Light Configuration
 
diff --git a/docs/feature_macros.md b/docs/feature_macros.md
index 29ba29fef..aa13fb97f 100644
--- a/docs/feature_macros.md
+++ b/docs/feature_macros.md
@@ -250,6 +250,8 @@ Parallel to `register_code` function, this sends the `<kc>` keyup event to the c
 
 This will send `register_code(<kc>)` and then `unregister_code(<kc>)`. This is useful if you want to send both the press and release events ("tap" the key, rather than hold it).
 
+If you're having issues with taps (un)registering, you can add a delay between the register and unregister events by setting `#define TAP_CODE_DELAY 100` in your `config.h` file. The value is in milliseconds.
+
 ### `clear_keyboard();`
 
 This will clear all mods and keys currently pressed.
diff --git a/quantum/quantum.c b/quantum/quantum.c
index 69692233e..a57d4f89f 100644
--- a/quantum/quantum.c
+++ b/quantum/quantum.c
@@ -132,6 +132,14 @@ void unregister_code16 (uint16_t code) {
   }
 }
 
+void tap_code16(uint16_t code) {
+  register_code16(code);
+  #if TAP_CODE_DELAY > 0
+    wait_ms(TAP_CODE_DELAY);
+  #endif
+  unregister_code16(code);
+}
+
 __attribute__ ((weak))
 bool process_action_kb(keyrecord_t *record) {
   return true;
diff --git a/quantum/quantum.h b/quantum/quantum.h
index 5920e4b13..0faf1af29 100644
--- a/quantum/quantum.h
+++ b/quantum/quantum.h
@@ -243,7 +243,7 @@ void shutdown_user(void);
 
 void register_code16(uint16_t code);
 void unregister_code16(uint16_t code);
-inline void tap_code16(uint16_t code) { register_code16(code); unregister_code16(code); }
+void tap_code16(uint16_t code);
 
 #ifdef BACKLIGHT_ENABLE
 void backlight_init_ports(void);
diff --git a/tmk_core/common/action.c b/tmk_core/common/action.c
index 8bdcd54e3..456d1e25f 100644
--- a/tmk_core/common/action.c
+++ b/tmk_core/common/action.c
@@ -851,6 +851,18 @@ void unregister_code(uint8_t code)
  *
  * FIXME: Needs documentation.
  */
+void tap_code(uint8_t code) {
+  register_code(code);
+  #if TAP_CODE_DELAY > 0
+    wait_ms(TAP_CODE_DELAY);
+  #endif
+  unregister_code(code);
+}
+
+/** \brief Utilities for actions. (FIXME: Needs better description)
+ *
+ * FIXME: Needs documentation.
+ */
 void register_mods(uint8_t mods)
 {
     if (mods) {
diff --git a/tmk_core/common/action.h b/tmk_core/common/action.h
index 833febe9c..5d797fd62 100644
--- a/tmk_core/common/action.h
+++ b/tmk_core/common/action.h
@@ -88,7 +88,7 @@ void process_record(keyrecord_t *record);
 void process_action(keyrecord_t *record, action_t action);
 void register_code(uint8_t code);
 void unregister_code(uint8_t code);
-inline void tap_code(uint8_t code) { register_code(code); unregister_code(code); }
+void tap_code(uint8_t code);
 void register_mods(uint8_t mods);
 void unregister_mods(uint8_t mods);
 //void set_mods(uint8_t mods);