drivers: led_strip: Add length function

Adds a length function which returns the length of the LED strip

Signed-off-by: Jamie McCrae <spam@helper3000.net>

drivers/led_strip/apa102.c

@@ -14,6 +14,7 @@
 
 struct apa102_config {
 	struct spi_dt_spec bus;
+	size_t length;
 };
 
 static int apa102_update(const struct device *dev, void *buf, size_t size)
@@ -80,6 +81,13 @@ static int apa102_update_channels(const struct device *dev, uint8_t *channels,
 	return -EINVAL;
 }
 
+static size_t apa102_length(const struct device *dev)
+{
+	const struct apa102_config *config = dev->config;
+
+	return config->length;
+}
+
 static int apa102_init(const struct device *dev)
 {
 	const struct apa102_config *config = dev->config;
@@ -94,6 +102,7 @@ static int apa102_init(const struct device *dev)
 static const struct led_strip_driver_api apa102_api = {
 	.update_rgb = apa102_update_rgb,
 	.update_channels = apa102_update_channels,
+	.length = apa102_length,
 };
 
 #define APA102_DEVICE(idx)						 \
@@ -102,6 +111,7 @@ static const struct led_strip_driver_api apa102_api = {
 			idx,						 \
 			SPI_OP_MODE_MASTER | SPI_TRANSFER_MSB | SPI_WORD_SET(8), \
 			0),						 \
+		.length = DT_INST_PROP(idx, chain_length),		 \
 	};								 \
 									 \
 	DEVICE_DT_INST_DEFINE(idx,					 \

drivers/led_strip/lpd880x.c

@@ -36,6 +36,7 @@ LOG_MODULE_REGISTER(lpd880x);
 
 struct lpd880x_config {
 	struct spi_dt_spec bus;
+	size_t length;
 };
 
 static int lpd880x_update(const struct device *dev, void *data, size_t size)
@@ -125,6 +126,13 @@ static int lpd880x_strip_update_channels(const struct device *dev,
 	return lpd880x_update(dev, channels, num_channels);
 }
 
+static size_t lpd880x_strip_length(const struct device *dev)
+{
+	const struct lpd880x_config *config = dev->config;
+
+	return config->length;
+}
+
 static int lpd880x_strip_init(const struct device *dev)
 {
 	const struct lpd880x_config *config = dev->config;
@@ -138,12 +146,14 @@ static int lpd880x_strip_init(const struct device *dev)
 }
 
 static const struct lpd880x_config lpd880x_config = {
-	.bus = SPI_DT_SPEC_INST_GET(0, LPD880X_SPI_OPERATION, 0)
+	.bus = SPI_DT_SPEC_INST_GET(0, LPD880X_SPI_OPERATION, 0),
+	.length = DT_INST_PROP(0, chain_length),
 };
 
 static const struct led_strip_driver_api lpd880x_strip_api = {
 	.update_rgb = lpd880x_strip_update_rgb,
 	.update_channels = lpd880x_strip_update_channels,
+	.length = lpd880x_strip_length,
 };
 
 DEVICE_DT_INST_DEFINE(0, lpd880x_strip_init, NULL,

drivers/led_strip/tlc5971.c

@@ -269,6 +269,13 @@ static int tlc5971_update_channels(const struct device *dev, uint8_t *channels,
 	return -ENOTSUP;
 }
 
+static size_t tlc5971_length(const struct device *dev)
+{
+	const struct tlc5971_config *cfg = dev->config;
+
+	return (size_t)cfg->num_pixels;
+}
+
 int tlc5971_set_global_brightness(const struct device *dev, struct led_rgb pixel)
 {
 	const struct tlc5971_config *cfg = dev->config;
@@ -334,6 +341,7 @@ static int tlc5971_init(const struct device *dev)
 static const struct led_strip_driver_api tlc5971_api = {
 	.update_rgb = tlc5971_update_rgb,
 	.update_channels = tlc5971_update_channels,
+	.length = tlc5971_length,
 };
 
 #define TLC5971_DATA_BUFFER_LENGTH(inst)                                                           \

drivers/led_strip/ws2812_gpio.c

@@ -28,6 +28,7 @@ struct ws2812_gpio_cfg {
 	struct gpio_dt_spec gpio;
 	uint8_t num_colors;
 	const uint8_t *color_mapping;
+	size_t length;
 };
 
 /*
@@ -187,9 +188,17 @@ static int ws2812_gpio_update_channels(const struct device *dev,
 	return -ENOTSUP;
 }
 
+static size_t ws2812_gpio_length(const struct device *dev)
+{
+	const struct ws2812_gpio_cfg *config = dev->config;
+
+	return config->length;
+}
+
 static const struct led_strip_driver_api ws2812_gpio_api = {
 	.update_rgb = ws2812_gpio_update_rgb,
 	.update_channels = ws2812_gpio_update_channels,
+	.length = ws2812_gpio_length,
 };
 
 /*
@@ -245,6 +254,7 @@ static const uint8_t ws2812_gpio_##idx##_color_mapping[] =		\
 		.gpio = GPIO_DT_SPEC_INST_GET(idx, gpios),		\
 		.num_colors = WS2812_NUM_COLORS(idx),			\
 		.color_mapping = ws2812_gpio_##idx##_color_mapping,	\
+		.length = DT_INST_PROP(idx, chain_length),		\
 	};								\
 									\
 	DEVICE_DT_INST_DEFINE(idx,					\

drivers/led_strip/ws2812_i2s.c

@@ -38,6 +38,7 @@ struct ws2812_i2s_cfg {
 	size_t tx_buf_bytes;
 	struct k_mem_slab *mem_slab;
 	uint8_t num_colors;
+	size_t length;
 	const uint8_t *color_mapping;
 	uint16_t reset_words;
 	uint32_t lrck_period;
@@ -170,6 +171,13 @@ static int ws2812_strip_update_channels(const struct device *dev, uint8_t *chann
 	return -ENOTSUP;
 }
 
+static size_t ws2812_strip_length(const struct device *dev)
+{
+	const struct ws2812_i2s_cfg *cfg = dev->config;
+
+	return cfg->length;
+}
+
 static int ws2812_i2s_init(const struct device *dev)
 {
 	const struct ws2812_i2s_cfg *cfg = dev->config;
@@ -218,6 +226,7 @@ static int ws2812_i2s_init(const struct device *dev)
 static const struct led_strip_driver_api ws2812_i2s_api = {
 	.update_rgb = ws2812_strip_update_rgb,
 	.update_channels = ws2812_strip_update_channels,
+	.length = ws2812_strip_length,
 };
 
 /* Integer division, but always rounds up: e.g. 10/3 = 4 */
@@ -250,6 +259,7 @@ static const struct led_strip_driver_api ws2812_i2s_api = {
 		.tx_buf_bytes = WS2812_I2S_BUFSIZE(idx),                                           \
 		.mem_slab = &ws2812_i2s_##idx##_slab,                                              \
 		.num_colors = WS2812_NUM_COLORS(idx),                                              \
+		.length = DT_INST_PROP(idx, chain_length),                                         \
 		.color_mapping = ws2812_i2s_##idx##_color_mapping,                                 \
 		.lrck_period = WS2812_I2S_LRCK_PERIOD_US(idx),                                     \
 		.extra_wait_time_us = DT_INST_PROP(idx, extra_wait_time),                          \

drivers/led_strip/ws2812_rpi_pico_pio.c

@@ -24,6 +24,7 @@ struct ws2812_led_strip_config {
 	const struct device *piodev;
 	const uint8_t gpio_pin;
 	uint8_t num_colors;
+	size_t length;
 	uint32_t frequency;
 	const uint8_t *const color_mapping;
 	uint16_t reset_delay;
@@ -115,9 +116,17 @@ static int ws2812_led_strip_update_channels(const struct device *dev, uint8_t *c
 	return -ENOTSUP;
 }
 
+static size_t ws2812_led_strip_length(const struct device *dev)
+{
+	const struct ws2812_led_strip_config *config = dev->config;
+
+	return config->length;
+}
+
 static const struct led_strip_driver_api ws2812_led_strip_api = {
 	.update_rgb = ws2812_led_strip_update_rgb,
 	.update_channels = ws2812_led_strip_update_channels,
+	.length = ws2812_led_strip_length,
 };
 
 /*
@@ -190,6 +199,7 @@ static int ws2812_rpi_pico_pio_init(const struct device *dev)
 		.piodev = DEVICE_DT_GET(DT_PARENT(DT_PARENT(node))),                               \
 		.gpio_pin = DT_GPIO_PIN_BY_IDX(node, gpios, 0),                                    \
 		.num_colors = DT_PROP_LEN(node, color_mapping),                                    \
+		.length = DT_PROP(node, chain_length),                                             \
 		.color_mapping = ws2812_led_strip_##node##_color_mapping,                          \
 		.reset_delay = DT_PROP(node, reset_delay),                                         \
 		.frequency = DT_PROP(node, frequency),                                             \

drivers/led_strip/ws2812_spi.c

@@ -44,6 +44,7 @@ struct ws2812_spi_cfg {
 	uint8_t zero_frame;
 	uint8_t num_colors;
 	const uint8_t *color_mapping;
+	size_t length;
 	uint16_t reset_delay;
 };
 
@@ -160,6 +161,13 @@ static int ws2812_strip_update_channels(const struct device *dev,
 	return -ENOTSUP;
 }
 
+static size_t ws2812_strip_length(const struct device *dev)
+{
+	const struct ws2812_spi_cfg *cfg = dev_cfg(dev);
+
+	return cfg->length;
+}
+
 static int ws2812_spi_init(const struct device *dev)
 {
 	const struct ws2812_spi_cfg *cfg = dev_cfg(dev);
@@ -191,6 +199,7 @@ static int ws2812_spi_init(const struct device *dev)
 static const struct led_strip_driver_api ws2812_spi_api = {
 	.update_rgb = ws2812_strip_update_rgb,
 	.update_channels = ws2812_strip_update_channels,
+	.length = ws2812_strip_length,
 };
 
 #define WS2812_SPI_NUM_PIXELS(idx) \
@@ -231,6 +240,7 @@ static const struct led_strip_driver_api ws2812_spi_api = {
 		.zero_frame = WS2812_SPI_ZERO_FRAME(idx),		 \
 		.num_colors = WS2812_NUM_COLORS(idx),			 \
 		.color_mapping = ws2812_spi_##idx##_color_mapping,	 \
+		.length = DT_INST_PROP(idx, chain_length),               \
 		.reset_delay = WS2812_RESET_DELAY(idx),			 \
 	};								 \
 									 \

dts/bindings/led_strip/apa,apa102.yaml

@@ -2,4 +2,4 @@ description: APA102 SPI LED strip
 
 compatible: "apa,apa102"
 
-include: spi-device.yaml
+include: [spi-device.yaml, led-strip.yaml]

dts/bindings/led_strip/greeled,lpd8803.yaml

@@ -5,4 +5,4 @@ description: GreeLed LPD8803 SPI LED strip
 
 compatible: "greeled,lpd8803"
 
-include: spi-device.yaml
+include: [spi-device.yaml, led-strip.yaml]

dts/bindings/led_strip/greeled,lpd8806.yaml

@@ -5,4 +5,4 @@ description: GreeLed LPD8806 SPI LED strip
 
 compatible: "greeled,lpd8806"
 
-include: spi-device.yaml
+include: [spi-device.yaml, led-strip.yaml]

include/zephyr/drivers/led_strip.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2017 Linaro Limited
+ * Copyright (c) 2024 Jamie McCrae
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -71,6 +72,14 @@ typedef int (*led_api_update_channels)(const struct device *dev,
 				       uint8_t *channels,
 				       size_t num_channels);
 
+/**
+ * @typedef led_api_length
+ * @brief Callback API for getting length of an LED strip.
+ *
+ * @see led_strip_length() for argument descriptions.
+ */
+typedef size_t (*led_api_length)(const struct device *dev);
+
 /**
  * @brief LED strip driver API
  *
@@ -79,6 +88,7 @@ typedef int (*led_api_update_channels)(const struct device *dev,
 __subsystem struct led_strip_driver_api {
 	led_api_update_rgb update_rgb;
 	led_api_update_channels update_channels;
+	led_api_length length;
 };
 
 /**
@@ -131,6 +141,21 @@ static inline int led_strip_update_channels(const struct device *dev,
 	return api->update_channels(dev, channels, num_channels);
 }
 
+/**
+ * @brief	Mandatory function to get chain length (in pixels) of an LED strip device.
+ *
+ * @param dev	LED strip device.
+ *
+ * @retval	Length of LED strip device.
+ */
+static inline size_t led_strip_length(const struct device *dev)
+{
+	const struct led_strip_driver_api *api =
+		(const struct led_strip_driver_api *)dev->api;
+
+	return api->length(dev);
+}
+
 #ifdef __cplusplus
 }
 #endif