rgblight.c: add remap feature (#5243)

* rgblight.c: add RGBLIGHT_LED_MAP support

* add code to keyboards/helix/rev2/keymaps/five_rows/config.h to test rgblight.c:RGBLIGHT_LED_MAP

* Test end. Revert "add code to keyboards/helix/rev2/keymaps/five_rows/config.h to test rgblight.c:RGBLIGHT_LED_MAP"

This reverts commit e7488d6f7338460b533d7d19a09deccb011000bf.

* update docs/feature_rgblight.md

* led_map[] move to PROGMEM

2 files changed, 63 insertions, 2 deletions

diff --git a/docs/feature_rgblight.md b/docs/feature_rgblight.md
index 23b6f1c94..800e59738 100644
--- a/docs/feature_rgblight.md
+++ b/docs/feature_rgblight.md
@@ -188,6 +188,53 @@ If you need to change your RGB lighting in code, for example in a macro to chang
 
 Additionally, [`rgblight_list.h`](https://github.com/qmk/qmk_firmware/blob/master/quantum/rgblight_list.h) defines several predefined shortcuts for various colors. Feel free to add to this list!
 
+## Changing the order of the LEDs
+
+If you want to make the logical order of LEDs different from the electrical connection order, you can do this by defining the `RGBLIGHT_LED_MAP` macro in your `config.h`.
+
+By defining `RGBLIGHT_LED_MAP` as in the example below, you can specify the LED with addressing in reverse order of the electrical connection order.
+
+```c
+// config.h
+
+#define RGBLED_NUM 10
+#define RGBLIGHT_LED_MAP { 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 }
+
+```
+
+For keyboards that use the RGB LEDs as a backlight for each key, you can also define it as in the example below.
+
+```c
+// config.h
+
+#define RGBLED_NUM 30
+
+/* RGB LED Conversion macro from physical array to electric array */
+#define LED_LAYOUT( \
+    L00, L01, L02, L03, L04, L05,  \
+    L10, L11, L12, L13, L14, L15,  \
+    L20, L21, L22, L23, L24, L25,  \
+    L30, L31, L32, L33, L34, L35,  \
+    L40, L41, L42, L43, L44, L45 ) \
+  { \
+    L05, L04, L03, L02, L01, L00,   \
+    L10, L11, L12, L13, L14, L15,   \
+    L25, L24, L23, L22, L21, L20,   \
+    L30, L31, L32, L33, L34, L35,   \
+    L46, L45, L44, L43, L42, L41    \
+  }
+
+/* RGB LED logical order map */
+/* Top->Bottom, Right->Left */
+#define RGBLIGHT_LED_MAP LED_LAYOUT( \
+  25, 20, 15, 10,  5,  0,       \
+  26, 21, 16, 11,  6,  1,       \
+  27, 22, 17, 12,  7,  2,       \
+  28, 23, 18, 13,  8,  3,       \
+  29, 24, 19, 14,  9,  4 )
+
+```
+
 ## Hardware Modification
 
 If your keyboard lacks onboard underglow LEDs, you may often be able to solder on an RGB LED strip yourself. You will need to find an unused pin to wire to the data pin of your LED strip. Some keyboards may break out unused pins from the MCU to make soldering easier. The other two pins, VCC and GND, must also be connected to the appropriate power pins.
diff --git a/quantum/rgblight.c b/quantum/rgblight.c
index 119ca1b9e..3042ff11e 100644
--- a/quantum/rgblight.c
+++ b/quantum/rgblight.c
@@ -51,6 +51,10 @@ static inline int is_static_effect(uint8_t mode) {
 #define MIN(a,b) (((a)<(b))?(a):(b))
 #define MAX(a,b) (((a)>(b))?(a):(b))
 
+#ifdef RGBLIGHT_LED_MAP
+const uint8_t led_map[] PROGMEM = RGBLIGHT_LED_MAP;
+#endif
+
 #ifdef RGBLIGHT_EFFECT_STATIC_GRADIENT
 __attribute__ ((weak))
 const uint16_t RGBLED_GRADIENT_RANGES[] PROGMEM = {360, 240, 180, 120, 90};
@@ -665,10 +669,20 @@ void rgblight_sethsv_slave(uint16_t hue, uint8_t sat, uint8_t val) {
 #ifndef RGBLIGHT_CUSTOM_DRIVER
 void rgblight_set(void) {
   if (rgblight_config.enable) {
+      LED_TYPE *ledp;
+    #ifdef RGBLIGHT_LED_MAP
+      LED_TYPE led0[RGBLED_NUM];
+      for(uint8_t i = 0; i < RGBLED_NUM; i++) {
+          led0[i] = led[pgm_read_byte(&led_map[i])];
+      }
+      ledp = led0;
+    #else
+      ledp = led;
+    #endif
     #ifdef RGBW
-      ws2812_setleds_rgbw(led, RGBLED_NUM);
+      ws2812_setleds_rgbw(ledp, RGBLED_NUM);
     #else
-      ws2812_setleds(led, RGBLED_NUM);
+      ws2812_setleds(ledp, RGBLED_NUM);
     #endif
   } else {
     for (uint8_t i = 0; i < RGBLED_NUM; i++) {