2 files changed, 32 insertions, 1 deletions
diff --git a/quantum/visualizer/visualizer.c b/quantum/visualizer/visualizer.c
index 62ebebceed..bff0df4947 100644
--- a/quantum/visualizer/visualizer.c
+++ b/quantum/visualizer/visualizer.c
@@ -64,6 +64,9 @@ static visualizer_keyboard_status_t current_status = {
     .mods = 0xFF,
     .leds = 0xFFFFFFFF,
     .suspended = false,
+#ifdef VISUALIZER_USER_DATA_SIZE
+    .user_data = {0}
+#endif
 };
 
 static bool same_status(visualizer_keyboard_status_t* status1, visualizer_keyboard_status_t* status2) {
@@ -71,11 +74,19 @@ static bool same_status(visualizer_keyboard_status_t* status1, visualizer_keyboa
         status1->default_layer == status2->default_layer &&
         status1->mods == status2->mods &&
         status1->leds == status2->leds &&
-        status1->suspended == status2->suspended;
+        status1->suspended == status2->suspended
+#ifdef VISUALIZER_USER_DATA_SIZE
+        && memcmp(status1->user_data, status2->user_data, VISUALIZER_USER_DATA_SIZE) == 0
+#endif
+    ;
 }
 
 static bool visualizer_enabled = false;
 
+#ifdef VISUALIZER_USER_DATA_SIZE
+static uint8_t user_data[VISUALIZER_USER_DATA_SIZE];
+#endif
+
 #define MAX_SIMULTANEOUS_ANIMATIONS 4
 static keyframe_animation_t* animations[MAX_SIMULTANEOUS_ANIMATIONS] = {};
 
@@ -431,6 +442,9 @@ static DECLARE_THREAD_FUNCTION(visualizerThread, arg) {
         .mods = 0xFF,
         .leds = 0xFFFFFFFF,
         .suspended = false,
+#ifdef VISUALIZER_USER_DATA_SIZE
+        .user_data = {0},
+#endif
     };
 
     visualizer_state_t state = {
@@ -590,6 +604,12 @@ uint8_t visualizer_get_mods() {
   return mods;
 }
 
+#ifdef VISUALIZER_USER_DATA_SIZE
+void visualizer_set_user_data(void* u) {
+    memcpy(user_data, u, VISUALIZER_USER_DATA_SIZE);
+}
+#endif
+
 void visualizer_update(uint32_t default_state, uint32_t state, uint8_t mods, uint32_t leds) {
     // Note that there's a small race condition here, the thread could read
     // a state where one of these are set but not the other. But this should
@@ -618,6 +638,9 @@ void visualizer_update(uint32_t default_state, uint32_t state, uint8_t mods, uin
             .leds = leds,
             .suspended = current_status.suspended,
         };
+#ifdef VISUALIZER_USER_DATA_SIZE
+       memcpy(new_status.user_data, user_data, VISUALIZER_USER_DATA_SIZE);
+#endif
         if (!same_status(&current_status, &new_status)) {
             changed = true;
             current_status = new_status;
diff --git a/quantum/visualizer/visualizer.h b/quantum/visualizer/visualizer.h
index 2c81cb9f71..beb8f2ab41 100644
--- a/quantum/visualizer/visualizer.h
+++ b/quantum/visualizer/visualizer.h
@@ -68,6 +68,9 @@ typedef struct {
     uint8_t mods;
     uint32_t leds; // See led.h for available statuses
     bool suspended;
+#ifdef VISUALIZER_USER_DATA_SIZE
+    uint8_t user_data[VISUALIZER_USER_DATA_SIZE];
+#endif
 } visualizer_keyboard_status_t;
 
 // The state struct is used by the various keyframe functions
@@ -146,6 +149,11 @@ bool keyframe_enable_lcd_and_backlight(keyframe_animation_t* animation, visualiz
 // directly from the initalize_user_visualizer function (the animation can be null)
 bool enable_visualization(keyframe_animation_t* animation, visualizer_state_t* state);
 
+// The master can set userdata which will be transferred to the slave
+#ifdef VISUALIZER_USER_DATA_SIZE
+void visualizer_set_user_data(void* user_data);
+#endif
+
 // These functions have to be implemented by the user
 void initialize_user_visualizer(visualizer_state_t* state);
 void update_user_visualizer_state(visualizer_state_t* state, visualizer_keyboard_status_t prev_status);