Use White channel on RGBW LEDs (#7678)

* Use White channel on RGBW LEDs

Co-authored-by: kwerdenker <sebastian.spindler@gmail.com>

* Manually apply white channel to array

* Move where convert_rgb_to_rgbw is called

* Fix type for rgbw led struct

* Add changes to Ergodox EZ

can revert if deemed necessary

* Revert "Add changes to Ergodox EZ"

This reverts commit aa44db198d40d758ca10470eb94615513592d1dd.

* Revert "Fix type for rgbw led struct"

This reverts commit c5c744cba040201cc0d124400773cf13f8a2cf22.

* Revert "Move where convert_rgb_to_rgbw is called"

This reverts commit cd7f17caf6dd30731c54b3be54490fe4519444f9.

* Revert changes and fix up functions

* Enable white channel for Ergodox EZ as well

* Only run conversion of rgblight is enabled

Co-authored-by: kwerdenker <sebastian.spindler@gmail.com>

5 files changed, 33 insertions, 4 deletions

diff --git a/keyboards/ergodox_ez/led_i2c.c b/keyboards/ergodox_ez/led_i2c.c
index 3e75a8cd08..4a7a02f468 100644
--- a/keyboards/ergodox_ez/led_i2c.c
+++ b/keyboards/ergodox_ez/led_i2c.c
@@ -51,7 +51,13 @@ void rgblight_set(void) {
 #endif
         }
     }
-
+#ifdef RGBW
+    else {
+        for (uint8_t i = 0; i < RGBLED_NUM; i++) {
+            convert_rgb_to_rgbw(&led[i]);
+        }
+    }
+#endif
 
     uint8_t led_num = RGBLED_NUM;
     i2c_init();
diff --git a/quantum/color.c b/quantum/color.c
index 1f398e2403..8bd52444fa 100644
--- a/quantum/color.c
+++ b/quantum/color.c
@@ -85,3 +85,17 @@ RGB hsv_to_rgb(HSV hsv) {
 
     return rgb;
 }
+
+#ifdef RGBW
+#ifndef MIN
+#    define MIN(a, b) ((a) < (b) ? (a) : (b))
+#endif
+void convert_rgb_to_rgbw(LED_TYPE *led) {
+    // Determine lowest value in all three colors, put that into
+    // the white channel and then shift all colors by that amount
+    led->w = MIN(led->r, MIN(led->g, led->b));
+    led->r -= led->w;
+    led->g -= led->w;
+    led->b -= led->w;
+}
+#endif
diff --git a/quantum/color.h b/quantum/color.h
index 6781646628..58d4f0407f 100644
--- a/quantum/color.h
+++ b/quantum/color.h
@@ -64,5 +64,7 @@ typedef struct PACKED {
 #endif
 
 RGB hsv_to_rgb(HSV hsv);
-
+#ifdef RGBW
+void convert_rgb_to_rgbw(LED_TYPE *led);
+#endif
 #endif  // COLOR_H
diff --git a/quantum/rgb_matrix_drivers.c b/quantum/rgb_matrix_drivers.c
index 9729a3064e..ea41b0d396 100644
--- a/quantum/rgb_matrix_drivers.c
+++ b/quantum/rgb_matrix_drivers.c
@@ -113,7 +113,7 @@ static inline void setled(int i, uint8_t r, uint8_t g, uint8_t b) {
     led[i].g = g;
     led[i].b = b;
 #    ifdef RGBW
-    led[i].w = 0;
+    convert_rgb_to_rgbw(led[i]);
 #    endif
 }
 
diff --git a/quantum/rgblight.c b/quantum/rgblight.c
index 7949bb688e..141dc2e7bc 100644
--- a/quantum/rgblight.c
+++ b/quantum/rgblight.c
@@ -611,6 +611,7 @@ void rgblight_set(void) {
 #    endif
         }
     }
+
 #    ifdef RGBLIGHT_LED_MAP
     LED_TYPE led0[RGBLED_NUM];
     for (uint8_t i = 0; i < RGBLED_NUM; i++) {
@@ -620,7 +621,13 @@ void rgblight_set(void) {
 #    else
     start_led = led + clipping_start_pos;
 #    endif
-    ws2812_setleds(start_led, num_leds);
+
+#ifdef RGBW
+    for (uint8_t i = 0; i < num_leds; i++) {
+        convert_rgb_to_rgbw(&start_led[i]);
+    }
+#endif
+   ws2812_setleds(start_led, num_leds);
 }
 #endif