drivers: led_strip: Add support for white channels in API

This commit implements support for RGBW LED strips. struct led_rgb currently supports a scratch uint8 for alignment/size reasons. This same space can also fit a white channel as used by some LEDs like the SK6812. To accomplish this a new config, CONFIG_LED_STRIP_WHITE_CHANNEL is added which replaces the .scratch parameter with a .w parameter that API users can set. The existing CONFIG_LED_STRIP_RGB_SCRATCH option is kept and mutually exclusive with this new parameter to distinguish LED strips like the APA102 that need the alignment, but don't support a white channel in hardware. Signed-off-by: J M <[email protected]>
zephyrproject-rtos · Jun 11, 2023 · 49dde20 · 49dde20
1 parent d14519c
commit 49dde20
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Showing 6 changed files with 30 additions and 5 deletions.
diff --git a/drivers/led_strip/Kconfig b/drivers/led_strip/Kconfig
@@ -27,6 +27,12 @@ config LED_STRIP_INIT_PRIORITY
 config LED_STRIP_RGB_SCRATCH
 	bool
 
+config LED_STRIP_WHITE_CHANNEL
+	bool "LED strip white channel"
+	depends on !LED_STRIP_RGB_SCRATCH
+	help
+		Enables support for a white channel in addition to RGB
+
 source "drivers/led_strip/Kconfig.lpd880x"
 
 source "drivers/led_strip/Kconfig.ws2812"

diff --git a/drivers/led_strip/Kconfig.ws2812 b/drivers/led_strip/Kconfig.ws2812
@@ -9,7 +9,7 @@
 
 menuconfig WS2812_STRIP
 	bool "WS2812 (and compatible) LED strip driver"
-	select LED_STRIP_RGB_SCRATCH
+	select WS2812_STRIP_WHITE_CHANNEL
 	help
 	  Enable LED strip driver for daisy chains of WS2812-ish (or WS2812B,
 	  WS2813, SK6812, Everlight B1414, or compatible) devices.
@@ -47,3 +47,9 @@ config WS2812_STRIP_GPIO
 	  controller.
 
 endchoice
+
+config WS2812_STRIP_WHITE_CHANNEL
+	bool "White channel"
+	select LED_STRIP_WHITE_CHANNEL
+	help
+		Enables support for white channels in the led_strip API.
diff --git a/drivers/led_strip/ws2812_gpio.c b/drivers/led_strip/ws2812_gpio.c
@@ -157,9 +157,12 @@ static int ws2812_gpio_update_rgb(const struct device *dev,
 
 		for (j = 0; j < config->num_colors; j++) {
 			switch (config->color_mapping[j]) {
-			/* White channel is not supported by LED strip API. */
 			case LED_COLOR_ID_WHITE:
+#ifdef CONFIG_LED_STRIP_WHITE_CHANNEL
+				*ptr++ = pixels[i].w;
+#else
 				*ptr++ = 0;
+#endif
 				break;
 			case LED_COLOR_ID_RED:
 				*ptr++ = pixels[i].r;

diff --git a/drivers/led_strip/ws2812_i2s.c b/drivers/led_strip/ws2812_i2s.c
@@ -110,9 +110,12 @@ static int ws2812_strip_update_rgb(const struct device *dev, struct led_rgb *pix
 			uint8_t pixel;
 
 			switch (cfg->color_mapping[j]) {
-			/* White channel is not supported by LED strip API. */
 			case LED_COLOR_ID_WHITE:
+#ifdef CONFIG_LED_STRIP_WHITE_CHANNEL
+				pixel = pixels[i].w;
+#else
 				pixel = 0;
+#endif
 				break;
 			case LED_COLOR_ID_RED:
 				pixel = pixels[i].r;

diff --git a/drivers/led_strip/ws2812_spi.c b/drivers/led_strip/ws2812_spi.c
@@ -124,9 +124,12 @@ static int ws2812_strip_update_rgb(const struct device *dev,
 			uint8_t pixel;
 
 			switch (cfg->color_mapping[j]) {
-			/* White channel is not supported by LED strip API. */
 			case LED_COLOR_ID_WHITE:
+#ifdef CONFIG_LED_STRIP_WHITE_CHANNEL
+				pixel = pixels[i].w;
+#else
 				pixel = 0;
+#endif
 				break;
 			case LED_COLOR_ID_RED:
 				pixel = pixels[i].r;

diff --git a/include/zephyr/drivers/led_strip.h b/include/zephyr/drivers/led_strip.h
@@ -24,13 +24,14 @@
 
 #include <zephyr/types.h>
 #include <zephyr/device.h>
+#include <zephyr/sys/__assert.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /**
- * @brief Color value for a single RGB LED.
+ * @brief Color value for a single RGB(W) LED.
  *
  * Individual strip drivers may ignore lower-order bits if their
  * resolution in any channel is less than a full byte.
@@ -42,6 +43,9 @@ struct led_rgb {
 	 * ignore.
 	 */
 	uint8_t scratch;
+#else defined(CONFIG_LED_STRIP_WHITE_CHANNEL)
+	/** White channel */
+	uint8_t w;
 #endif
 	/** Red channel */
 	uint8_t r;