Add RGBW support to PWM and SPI drivers for ChibiOS (#14327)

* Add RGBW support to PWM and SPI drivers for ChibiOS

* Apply suggestions from code review

Co-authored-by: Ryan <fauxpark@gmail.com>

Co-authored-by: Ryan <fauxpark@gmail.com>

2 files changed, 44 insertions, 9 deletions

diff --git a/platforms/chibios/drivers/ws2812_pwm.c b/platforms/chibios/drivers/ws2812_pwm.c
index 48d81cc87..c17b9cd4e 100644
--- a/platforms/chibios/drivers/ws2812_pwm.c
+++ b/platforms/chibios/drivers/ws2812_pwm.c
@@ -5,7 +5,9 @@
 /* Adapted from https://github.com/joewa/WS2812-LED-Driver_ChibiOS/ */
 
 #ifdef RGBW
-#    error "RGBW not supported"
+#    define WS2812_CHANNELS 4
+#else
+#    define WS2812_CHANNELS 3
 #endif
 
 #ifndef WS2812_PWM_DRIVER
@@ -68,8 +70,9 @@
  * The reset period for each frame is defined in WS2812_TRST_US.
  * Calculate the number of zeroes to add at the end assuming 1.25 uS/bit:
  */
+#define WS2812_COLOR_BITS (WS2812_CHANNELS * 8)
 #define WS2812_RESET_BIT_N (1000 * WS2812_TRST_US / 1250)
-#define WS2812_COLOR_BIT_N (RGBLED_NUM * 24)                   /**< Number of data bits */
+#define WS2812_COLOR_BIT_N (RGBLED_NUM * WS2812_COLOR_BITS)    /**< Number of data bits */
 #define WS2812_BIT_N (WS2812_COLOR_BIT_N + WS2812_RESET_BIT_N) /**< Total number of bits in a frame */
 
 /**
@@ -114,7 +117,7 @@
  *
  * @return                          The bit index
  */
-#define WS2812_BIT(led, byte, bit) (24 * (led) + 8 * (byte) + (7 - (bit)))
+#define WS2812_BIT(led, byte, bit) (WS2812_COLOR_BITS * (led) + 8 * (byte) + (7 - (bit)))
 
 #if (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_GRB)
 /**
@@ -228,6 +231,20 @@
 #    define WS2812_BLUE_BIT(led, bit) WS2812_BIT((led), 0, (bit))
 #endif
 
+#ifdef RGBW
+/**
+ * @brief   Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given white bit
+ *
+ * @note    The white byte is the last byte in the color packet
+ *
+ * @param[in] led:                  The led index [0, @ref WS2812_LED_N)
+ * @param[in] bit:                  The bit index [0, 7]
+ *
+ * @return                          The bit index
+ */
+#    define WS2812_WHITE_BIT(led, bit) WS2812_BIT((led), 3, (bit))
+#endif
+
 /* --- PRIVATE VARIABLES ---------------------------------------------------- */
 
 static uint32_t ws2812_frame_buffer[WS2812_BIT_N + 1]; /**< Buffer for a frame */
@@ -296,6 +313,17 @@ void ws2812_write_led(uint16_t led_number, uint8_t r, uint8_t g, uint8_t b) {
         ws2812_frame_buffer[WS2812_BLUE_BIT(led_number, bit)]  = ((b >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0;
     }
 }
+void ws2812_write_led_rgbw(uint16_t led_number, uint8_t r, uint8_t g, uint8_t b, uint8_t w) {
+    // Write color to frame buffer
+    for (uint8_t bit = 0; bit < 8; bit++) {
+        ws2812_frame_buffer[WS2812_RED_BIT(led_number, bit)]   = ((r >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0;
+        ws2812_frame_buffer[WS2812_GREEN_BIT(led_number, bit)] = ((g >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0;
+        ws2812_frame_buffer[WS2812_BLUE_BIT(led_number, bit)]  = ((b >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0;
+#ifdef RGBW
+        ws2812_frame_buffer[WS2812_WHITE_BIT(led_number, bit)] = ((w >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0;
+#endif
+    }
+}
 
 // Setleds for standard RGB
 void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) {
@@ -306,6 +334,10 @@ void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) {
     }
 
     for (uint16_t i = 0; i < leds; i++) {
+#ifdef RGBW
+        ws2812_write_led_rgbw(i, ledarray[i].r, ledarray[i].g, ledarray[i].b, ledarray[i].w);
+#else
         ws2812_write_led(i, ledarray[i].r, ledarray[i].g, ledarray[i].b);
+#endif
     }
 }
diff --git a/platforms/chibios/drivers/ws2812_spi.c b/platforms/chibios/drivers/ws2812_spi.c
index 589bf85c3..62722f466 100644
--- a/platforms/chibios/drivers/ws2812_spi.c
+++ b/platforms/chibios/drivers/ws2812_spi.c
@@ -3,10 +3,6 @@
 
 /* Adapted from https://github.com/gamazeps/ws2812b-chibios-SPIDMA/ */
 
-#ifdef RGBW
-#    error "RGBW not supported"
-#endif
-
 // Define the spi your LEDs are plugged to here
 #ifndef WS2812_SPI
 #    define WS2812_SPI SPID1
@@ -74,8 +70,12 @@
 #endif
 
 #define BYTES_FOR_LED_BYTE 4
-#define NB_COLORS 3
-#define BYTES_FOR_LED (BYTES_FOR_LED_BYTE * NB_COLORS)
+#ifdef RGBW
+#    define WS2812_CHANNELS 4
+#else
+#    define WS2812_CHANNELS 3
+#endif
+#define BYTES_FOR_LED (BYTES_FOR_LED_BYTE * WS2812_CHANNELS)
 #define DATA_SIZE (BYTES_FOR_LED * RGBLED_NUM)
 #define RESET_SIZE (1000 * WS2812_TRST_US / (2 * 1250))
 #define PREAMBLE_SIZE 4
@@ -116,6 +116,9 @@ static void set_led_color_rgb(LED_TYPE color, int pos) {
     for (int j = 0; j < 4; j++) tx_start[BYTES_FOR_LED * pos + BYTES_FOR_LED_BYTE + j] = get_protocol_eq(color.g, j);
     for (int j = 0; j < 4; j++) tx_start[BYTES_FOR_LED * pos + BYTES_FOR_LED_BYTE * 2 + j] = get_protocol_eq(color.r, j);
 #endif
+#ifdef RGBW
+    for (int j = 0; j < 4; j++) tx_start[BYTES_FOR_LED * pos + BYTES_FOR_LED_BYTE * 4 + j] = get_protocol_eq(color.w, j);
+#endif
 }
 
 void ws2812_init(void) {