Add ability for boards to provide a custom pixel order in neopixelWrite()

cores/esp32/esp32-hal-rgb-led.c

@@ -1,3 +1,17 @@
+// Copyright 2024 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 #include "soc/soc_caps.h"
 
 #include "esp32-hal-rgb-led.h"
@@ -15,7 +29,40 @@ void neopixelWrite(uint8_t pin, uint8_t red_val, uint8_t green_val, uint8_t blue
     return;
   }
 
-  int color[] = {green_val, red_val, blue_val};  // Color coding is in order GREEN, RED, BLUE
+#if defined RGB_BUILTIN_LED_COLOR_ORDER
+  // the onboard RGB LED has a different color order
+  const int color[3];
+  switch (RGB_BUILTIN_LED_COLOR_ORDER) {
+    case LED_COLOR_ORDER_RGB:
+      color[0] = red_val;
+      color[1] = green_val;
+      color[2] = blue_val;
+      break;
+    case LED_COLOR_ORDER_BGR:
+      color[0] = blue_val;
+      color[1] = green_val;
+      color[2] = red_val;
+      break;
+    case LED_COLOR_ORDER_BRG:
+      color[0] = blue_val;
+      color[1] = red_val;
+      color[2] = green_val;
+      break;
+    case LED_COLOR_ORDER_RBG:
+      color[0] = red_val;
+      color[1] = blue_val;
+      color[2] = green_val;
+      break;
+    case LED_COLOR_ORDER_GBR:
+      color[0] = green_val;
+      color[1] = blue_val;
+      color[2] = red_val;
+  }
+#else
+  // default WS2812B color order is G, R, B
+  const int color[3] = {green_val, red_val, blue_val};
+#endif
+
   int i = 0;
   for (int col = 0; col < 3; col++) {
     for (int bit = 0; bit < 8; bit++) {

cores/esp32/esp32-hal-rgb-led.h

@@ -11,6 +11,15 @@ extern "C" {
 #define RGB_BRIGHTNESS 64
 #endif
 
+typedef enum {
+  LED_COLOR_ORDER_RGB,
+  LED_COLOR_ORDER_BGR,
+  LED_COLOR_ORDER_BRG,
+  LED_COLOR_ORDER_RBG,
+  LED_COLOR_ORDER_GBR,
+  LED_COLOR_ORDER_GRB
+} rgb_led_color_order_t;
+
 void neopixelWrite(uint8_t pin, uint8_t red_val, uint8_t green_val, uint8_t blue_val);
 
 #ifdef __cplusplus

variants/lolin_s3_mini/pins_arduino.h

@@ -12,6 +12,9 @@ static const uint8_t LED_BUILTIN = 47 + SOC_GPIO_PIN_COUNT;
 #define LED_BUILTIN    LED_BUILTIN  // allow testing #ifdef LED_BUILTIN
 #define RGB_BUILTIN    LED_BUILTIN
 #define RGB_BRIGHTNESS 64
+// This board has a builtin RGB LED that works with a different signal color order
+// Other order options can be found in https://github.com/espressif/arduino-esp32/blob/master/cores/esp32/esp32-hal-rgb-led.h
+#define RGB_BUILTIN_LED_COLOR_ORDER LED_COLOR_ORDER_RGB
 
 static const uint8_t TX = 43;
 static const uint8_t RX = 44;