Relocate base WS2812 code (#24850)

drivers/led/ws2812.c

@@ -0,0 +1,15 @@
+// Copyright 2024 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "ws2812.h"
+
+#if defined(WS2812_RGBW)
+void ws2812_rgb_to_rgbw(ws2812_led_t *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

drivers/led/ws2812.h

@@ -0,0 +1,97 @@
+/*
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "util.h"
+
+/*
+ * The WS2812 datasheets define T1H 900ns, T0H 350ns, T1L 350ns, T0L 900ns. Hence, by default, these
+ * are chosen to be conservative and avoid problems rather than for maximum throughput; in the code,
+ * this is done by default using a WS2812_TIMING parameter that accounts for the whole window (1250ns)
+ * and defining T1H and T0H; T1L and T0L are obtained by subtracting their low counterparts from the window.
+ *
+ * However, there are certain "WS2812"-like LEDs, like the SK6812s, which work in a similar
+ * communication topology but use different timings for the window and the T1L, T1H, T0L and T0H.
+ * This means that, albeit the same driver being applicable, the timings must be adapted.
+ */
+
+#ifndef WS2812_TIMING
+#    define WS2812_TIMING 1250
+#endif
+
+#ifndef WS2812_T1H
+#    define WS2812_T1H 900 // Width of a 1 bit in ns
+#endif
+
+#ifndef WS2812_T1L
+#    define WS2812_T1L (WS2812_TIMING - WS2812_T1H) // Width of a 1 bit in ns
+#endif
+
+#ifndef WS2812_T0H
+#    define WS2812_T0H 350 // Width of a 0 bit in ns
+#endif
+
+#ifndef WS2812_T0L
+#    define WS2812_T0L (WS2812_TIMING - WS2812_T0H) // Width of a 0 bit in ns
+#endif
+
+/*
+ * Older WS2812s can handle a reset time (TRST) of 50us, but recent
+ * component revisions require a minimum of 280us.
+ */
+#if !defined(WS2812_TRST_US)
+#    define WS2812_TRST_US 280
+#endif
+
+#if defined(RGBLIGHT_WS2812)
+#    define WS2812_LED_COUNT RGBLIGHT_LED_COUNT
+#elif defined(RGB_MATRIX_WS2812)
+#    define WS2812_LED_COUNT RGB_MATRIX_LED_COUNT
+#endif
+
+#define WS2812_BYTE_ORDER_RGB 0
+#define WS2812_BYTE_ORDER_GRB 1
+#define WS2812_BYTE_ORDER_BGR 2
+
+#ifndef WS2812_BYTE_ORDER
+#    define WS2812_BYTE_ORDER WS2812_BYTE_ORDER_GRB
+#endif
+
+typedef struct PACKED ws2812_led_t {
+#if (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_GRB)
+    uint8_t g;
+    uint8_t r;
+    uint8_t b;
+#elif (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_RGB)
+    uint8_t r;
+    uint8_t g;
+    uint8_t b;
+#elif (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_BGR)
+    uint8_t b;
+    uint8_t g;
+    uint8_t r;
+#endif
+#ifdef WS2812_RGBW
+    uint8_t w;
+#endif
+} ws2812_led_t;
+
+void ws2812_init(void);
+void ws2812_set_color(int index, uint8_t red, uint8_t green, uint8_t blue);
+void ws2812_set_color_all(uint8_t red, uint8_t green, uint8_t blue);
+void ws2812_flush(void);
+
+void ws2812_rgb_to_rgbw(ws2812_led_t *led);