drivers/led_strip/tlc5971.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*
  * Copyright (c) 2022 Esco Medical ApS
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 #define DT_DRV_COMPAT ti_tlc5971

 #include <zephyr/kernel.h>
 #include <zephyr/drivers/spi.h>
 #include <zephyr/drivers/led_strip.h>
 #include <zephyr/drivers/led_strip/tlc5971.h>
 #include <zephyr/dt-bindings/led/led.h>
 #include <zephyr/sys/util.h>

 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(tlc5971, CONFIG_LED_STRIP_LOG_LEVEL);

 struct tlc5971_config {
 	struct spi_dt_spec bus;
 	const uint8_t *color_mapping;
 	uint8_t num_pixels;
 	uint8_t num_colors;
 };

 struct tlc5971_data {
 	uint8_t *data_buffer;
 	uint8_t gbc_color_1;
 	uint8_t gbc_color_2;
 	uint8_t gbc_color_3;
 	uint8_t control_data;
 };

 /** SPI operation word constant, SPI mode 0, CPOL = 0, CPHA = 0 */
 #define TLC5971_SPI_OPERATION (SPI_OP_MODE_MASTER | SPI_TRANSFER_MSB | SPI_WORD_SET(8))

 /** Number of supported colors */
 #define TLC5971_NUMBER_OF_COLORS 3

 /**
  * @brief Number of RGB pixels per TLC5791 device
  *
  * The TLC5971 has 4x RGB outputs per device, where each RGB group constitues a pixel from this
  * drivers point of view.
  */
 #define TLC5971_PIXELS_PER_DEVICE 4

 /** Length in bytes of data packet per TLC5791 device */
 #define TLC5971_PACKET_LEN 28

 /** write command for writing control data and GS data to internal registers */
 #define TLC5971_WRITE_COMMAND 0x25

 /** GS reference clock select bit in FC data (0 = internal oscillator clock, 1 = SCKI clock). */
 #define TLC5971_BYTE27_CTRL_BIT_EXTGCK BIT(0)

 /** GS reference clock edge select bit for OUTXn on-off timing control in FC data */
 #define TLC5971_BYTE27_CTRL_BIT_OUTTMG BIT(1)

 /** Constant-current output enable bit in FC data (0 = output control enabled, 1 = blank). */
 #define TLC5971_BYTE26_CTRL_BIT_BLANK BIT(5)

 /** Auto display repeat mode enable bit in FC data (0 = disabled, 1 = enabled). */
 #define TLC5971_BYTE26_CTRL_BIT_DSPRPT BIT(6)

 /** Display timing reset mode enable bit in FC data (0 = disabled, 1 = enabled). */
 #define TLC5971_BYTE26_CTRL_BIT_TMGRST BIT(7)

 /** Bit mask for write cmd in data byte 27 */
 #define TLC5971_BYTE27_WRITE_CMD_MASK GENMASK(7, 2)

 /** Bit mask for control bits in data byte 27 */
 #define TLC5971_BYTE27_CTRL_MASK GENMASK(1, 0)

 /** Bit mask for control bits in data byte 26 */
 #define TLC5971_BYTE26_CTRL_MASK GENMASK(7, 5)

 /** Bit mask for global brightness control for color 1 in data byte 26, upper 5 bits of GBC */
 #define TLC5971_BYTE26_GBC1_MASK GENMASK(4, 0)

 /** Bit mask for global brightness control for color 1 in data byte 25, lower 2 bits of GBC */
 #define TLC5971_BYTE25_GBC1_MASK GENMASK(7, 6)

 /** Bit mask for global brightness control for color 2 in data byte 25, upper 6 bits of GBC */
 #define TLC5971_BYTE25_GBC2_MASK GENMASK(5, 0)

 /** Bit mask for global brightness control for color 2 in data byte 24, lower 1 bits of GBC */
 #define TLC5971_BYTE24_GBC2_MASK BIT(7)

 /** Bit mask for global brightness control for color 3 in data byte 24, all 7 bits of GBC */
 #define TLC5971_BYTE24_GBC3_MASK GENMASK(6, 0)

 /**
  * @brief create data byte 27 from control data
  *
  * @param control_data control bits
  * @return uint8_t the serialized data byte 27
  */
 static inline uint8_t tlc5971_data_byte27(uint8_t control_data)
 {
 	return FIELD_PREP(TLC5971_BYTE27_WRITE_CMD_MASK, TLC5971_WRITE_COMMAND) |
 	       FIELD_PREP(TLC5971_BYTE27_CTRL_MASK, control_data);
 }

 /**
  * @brief create data byte 26 from control data and color 1 GBC
  *
  * @param control_data control bits
  * @param gbc_color_1 global brightness control for color 1 LEDs
  * @return uint8_t the serialized data byte 26
  */
 static inline uint8_t tlc5971_data_byte26(uint8_t control_data, uint8_t gbc_color_1)
 {
 	return FIELD_PREP(TLC5971_BYTE26_CTRL_MASK, control_data) |
 	       FIELD_PREP(TLC5971_BYTE26_GBC1_MASK, (gbc_color_1 >> 2));
 }

 /**
  * @brief create data byte 25 from color 1 and 2 GBC
  *
  * @param gbc_color_1 global brightness control for color 1 LEDs
  * @param gbc_color_2 global brightness control for color 2 LEDs
  * @return uint8_t the serialized data byte 25
  */
 static inline uint8_t tlc5971_data_byte25(uint8_t gbc_color_1, uint8_t gbc_color_2)
 {
 	return FIELD_PREP(TLC5971_BYTE25_GBC1_MASK, gbc_color_1) |
 	       FIELD_PREP(TLC5971_BYTE25_GBC2_MASK, (gbc_color_2 >> 1));
 }

 /**
  * @brief create data byte 24 from color 2 and 3 GBC
  *
  * @param gbc_color_2 global brightness control for color 2 LEDs
  * @param gbc_color_3 global brightness control for color 3 LEDs
  * @return uint8_t the serialized data byte 24
  */
 static inline uint8_t tlc5971_data_byte24(uint8_t gbc_color_2, uint8_t gbc_color_3)
 {
 	return FIELD_PREP(TLC5971_BYTE24_GBC2_MASK, gbc_color_2) |
 	       FIELD_PREP(TLC5971_BYTE24_GBC3_MASK, gbc_color_3);
 }

 /**
  * @brief map user colors to tlc5971 color order
  *
  * @param color_id color id from color mapping
  * @param pixel_data rgb data to be mapped
  * @return the mapped color value
  */
 static uint8_t tlc5971_map_color(int color_id, const struct led_rgb *pixel_data)
 {
 	uint8_t temp = 0;

 	switch (color_id) {
 	case LED_COLOR_ID_RED:
 		temp = pixel_data->r;
 		break;
 	case LED_COLOR_ID_GREEN:
 		temp = pixel_data->g;
 		break;
 	case LED_COLOR_ID_BLUE:
 		temp = pixel_data->b;
 		break;
 	default:
 		temp = 0;
 		break;
 	}

 	return temp;
 }

 /**
  * @brief serialize control data and pixel data for device daisy chain
  *
  * the serializer only supports "full" devices, meaning each device is expected
  * to be mounted with all 4 LEDs.
  *
  * @param dev device pointer
  * @param pixels pixel RGB data for daisy chain
  * @param num_pixels number of pixels in daisy chain
  */
 static void tlc5971_fill_data_buffer(const struct device *dev, struct led_rgb *pixels,
 				     size_t num_pixels)
 {
 	const struct tlc5971_config *cfg = dev->config;
 	struct tlc5971_data *data = dev->data;
 	uint8_t *data_buffer = data->data_buffer;
 	int count = 0;

 	/*
 	 * tlc5971 device order is reversed as the rgb data for the last device in the daisy chain
 	 * should be transmitted first.
 	 */
 	for (int device = (num_pixels / TLC5971_PIXELS_PER_DEVICE) - 1; device >= 0; device--) {
 		/*
 		 * The SPI frame format expects a BGR color order for the global brightness control
 		 * values, but since the led_strip API allows custom color mappings, we simply use
 		 * color_x terms to keep things generic.
 		 */
 		data_buffer[count++] = tlc5971_data_byte27(data->control_data);
 		data_buffer[count++] = tlc5971_data_byte26(data->control_data, data->gbc_color_1);
 		data_buffer[count++] = tlc5971_data_byte25(data->gbc_color_1, data->gbc_color_2);
 		data_buffer[count++] = tlc5971_data_byte24(data->gbc_color_2, data->gbc_color_3);

 		for (int pixel = (TLC5971_PIXELS_PER_DEVICE - 1); pixel >= 0; pixel--) {
 			/* data is "reversed" so RGB0 comes last, i.e at byte 0 */
 			const struct led_rgb *pixel_data =
 				&pixels[(device * TLC5971_PIXELS_PER_DEVICE) + pixel];

 			/*
 			 * Convert pixel data into SPI frames, mapping user colors to tlc5971
 			 * data frame color order (BGR).
 			 */
 			for (int color = 0; color < cfg->num_colors; color++) {
 				uint8_t temp =
 					tlc5971_map_color(cfg->color_mapping[color], pixel_data);

 				/*
 				 * The tlc5971 rgb values are 16 bit but zephyr's rgb values are
 				 * 8 bit. Simply upscale to 16 bit by using the 8 bit value for both
 				 * LSB and MSB of the 16 bit word.
 				 */
 				data_buffer[count++] = temp;
 				data_buffer[count++] = temp;
 			}
 		}
 	}
 }

 static int tlc5971_transmit_data(const struct device *dev, size_t num_pixels)
 {
 	const struct tlc5971_config *cfg = dev->config;
 	struct tlc5971_data *data = dev->data;

 	struct spi_buf buf = {
 		.buf = data->data_buffer,
 		.len = (num_pixels / TLC5971_PIXELS_PER_DEVICE) * TLC5971_PACKET_LEN,
 	};

 	const struct spi_buf_set tx = {
 		.buffers = &buf,
 		.count = 1,
 	};

 	return spi_write_dt(&cfg->bus, &tx);
 }

 static int tlc5971_update_rgb(const struct device *dev, struct led_rgb *pixels, size_t num_pixels)
 {
 	tlc5971_fill_data_buffer(dev, pixels, num_pixels);

 	return tlc5971_transmit_data(dev, num_pixels);
 }

 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;
 	struct tlc5971_data *data = dev->data;
 	int res = -EINVAL;

 	if ((pixel.r <= TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX) &&
 	    (pixel.g <= TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX) &&
 	    (pixel.b <= TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX)) {
 		data->gbc_color_1 = tlc5971_map_color(cfg->color_mapping[0], &pixel);
 		data->gbc_color_2 = tlc5971_map_color(cfg->color_mapping[1], &pixel);
 		data->gbc_color_3 = tlc5971_map_color(cfg->color_mapping[2], &pixel);
 		res = 0;
 	}

 	return res;
 }

 static int tlc5971_init(const struct device *dev)
 {
 	const struct tlc5971_config *cfg = dev->config;
 	struct tlc5971_data *data = dev->data;

 	if (!spi_is_ready_dt(&cfg->bus)) {
 		LOG_ERR("%s: SPI device %s not ready", dev->name, cfg->bus.bus->name);
 		return -ENODEV;
 	}

 	if ((cfg->num_pixels % TLC5971_PIXELS_PER_DEVICE) != 0) {
 		LOG_ERR("%s: chain length must be multiple of 4", dev->name);
 		return -EINVAL;
 	}

 	if (cfg->num_colors != TLC5971_NUMBER_OF_COLORS) {
 		LOG_ERR("%s: the tlc5971 only supports %i colors", dev->name,
 			TLC5971_NUMBER_OF_COLORS);
 		return -EINVAL;
 	}

 	for (int i = 0; i < cfg->num_colors; i++) {
 		switch (cfg->color_mapping[i]) {
 		case LED_COLOR_ID_RED:
 		case LED_COLOR_ID_GREEN:
 		case LED_COLOR_ID_BLUE:
 			break;
 		default:
 			LOG_ERR("%s: invalid color mapping", dev->name);
 			return -EINVAL;
 		}
 	}

 	/*
 	 * set up sane defaults for control data.
 	 * unblanks leds, enables auto display repeat, enables timing resetm uses internal clock for
 	 * PWM generation and sets the GS reference clock edge select to rising edge
 	 */
 	data->control_data = TLC5971_BYTE27_CTRL_BIT_OUTTMG | TLC5971_BYTE26_CTRL_BIT_DSPRPT |
 			     TLC5971_BYTE26_CTRL_BIT_TMGRST;

 	return 0;
 }

 static const struct led_strip_driver_api tlc5971_api = {
 	.update_rgb = tlc5971_update_rgb,
 	.length = tlc5971_length,
 };

 #define TLC5971_DATA_BUFFER_LENGTH(inst)                                                           \
 	(DT_INST_PROP(inst, chain_length) / TLC5971_PIXELS_PER_DEVICE) * TLC5971_PACKET_LEN

 #define TLC5971_DEVICE(inst)                                                                       \
 	static const uint8_t tlc5971_##inst##_color_mapping[] = DT_INST_PROP(inst, color_mapping); \
 	static const struct tlc5971_config tlc5971_##inst##_config = {                             \
 		.bus = SPI_DT_SPEC_INST_GET(inst, TLC5971_SPI_OPERATION, 0),                       \
 		.num_pixels = DT_INST_PROP(inst, chain_length),                                    \
 		.num_colors = DT_INST_PROP_LEN(inst, color_mapping),                               \
 		.color_mapping = tlc5971_##inst##_color_mapping,                                   \
 	};                                                                                         \
 	static uint8_t tlc5971_##inst##_data_buffer[TLC5971_DATA_BUFFER_LENGTH(inst)];             \
 	static struct tlc5971_data tlc5971_##inst##_data = {                                       \
 		.data_buffer = tlc5971_##inst##_data_buffer,                                       \
 		.gbc_color_1 = TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX,                              \
 		.gbc_color_2 = TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX,                              \
 		.gbc_color_3 = TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX,                              \
 	};                                                                                         \
 	DEVICE_DT_INST_DEFINE(inst, tlc5971_init, NULL, &tlc5971_##inst##_data,                    \
 			      &tlc5971_##inst##_config, POST_KERNEL,                               \
 			      CONFIG_LED_STRIP_INIT_PRIORITY, &tlc5971_api);

 DT_INST_FOREACH_STATUS_OKAY(TLC5971_DEVICE)
	/*
	* Copyright (c) 2022 Esco Medical ApS
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	#define DT_DRV_COMPAT ti_tlc5971

	#include <zephyr/kernel.h>
	#include <zephyr/drivers/spi.h>
	#include <zephyr/drivers/led_strip.h>
	#include <zephyr/drivers/led_strip/tlc5971.h>
	#include <zephyr/dt-bindings/led/led.h>
	#include <zephyr/sys/util.h>

	#include <zephyr/logging/log.h>
	LOG_MODULE_REGISTER(tlc5971, CONFIG_LED_STRIP_LOG_LEVEL);

	struct tlc5971_config {
	struct spi_dt_spec bus;
	const uint8_t *color_mapping;
	uint8_t num_pixels;
	uint8_t num_colors;
	};

	struct tlc5971_data {
	uint8_t *data_buffer;
	uint8_t gbc_color_1;
	uint8_t gbc_color_2;
	uint8_t gbc_color_3;
	uint8_t control_data;
	};

	/** SPI operation word constant, SPI mode 0, CPOL = 0, CPHA = 0 */
	#define TLC5971_SPI_OPERATION (SPI_OP_MODE_MASTER \| SPI_TRANSFER_MSB \| SPI_WORD_SET(8))

	/** Number of supported colors */
	#define TLC5971_NUMBER_OF_COLORS 3

	/**
	* @brief Number of RGB pixels per TLC5791 device
	*
	* The TLC5971 has 4x RGB outputs per device, where each RGB group constitues a pixel from this
	* drivers point of view.
	*/
	#define TLC5971_PIXELS_PER_DEVICE 4

	/** Length in bytes of data packet per TLC5791 device */
	#define TLC5971_PACKET_LEN 28

	/** write command for writing control data and GS data to internal registers */
	#define TLC5971_WRITE_COMMAND 0x25

	/** GS reference clock select bit in FC data (0 = internal oscillator clock, 1 = SCKI clock). */
	#define TLC5971_BYTE27_CTRL_BIT_EXTGCK BIT(0)

	/** GS reference clock edge select bit for OUTXn on-off timing control in FC data */
	#define TLC5971_BYTE27_CTRL_BIT_OUTTMG BIT(1)

	/** Constant-current output enable bit in FC data (0 = output control enabled, 1 = blank). */
	#define TLC5971_BYTE26_CTRL_BIT_BLANK BIT(5)

	/** Auto display repeat mode enable bit in FC data (0 = disabled, 1 = enabled). */
	#define TLC5971_BYTE26_CTRL_BIT_DSPRPT BIT(6)

	/** Display timing reset mode enable bit in FC data (0 = disabled, 1 = enabled). */
	#define TLC5971_BYTE26_CTRL_BIT_TMGRST BIT(7)

	/** Bit mask for write cmd in data byte 27 */
	#define TLC5971_BYTE27_WRITE_CMD_MASK GENMASK(7, 2)

	/** Bit mask for control bits in data byte 27 */
	#define TLC5971_BYTE27_CTRL_MASK GENMASK(1, 0)

	/** Bit mask for control bits in data byte 26 */
	#define TLC5971_BYTE26_CTRL_MASK GENMASK(7, 5)

	/** Bit mask for global brightness control for color 1 in data byte 26, upper 5 bits of GBC */
	#define TLC5971_BYTE26_GBC1_MASK GENMASK(4, 0)

	/** Bit mask for global brightness control for color 1 in data byte 25, lower 2 bits of GBC */
	#define TLC5971_BYTE25_GBC1_MASK GENMASK(7, 6)

	/** Bit mask for global brightness control for color 2 in data byte 25, upper 6 bits of GBC */
	#define TLC5971_BYTE25_GBC2_MASK GENMASK(5, 0)

	/** Bit mask for global brightness control for color 2 in data byte 24, lower 1 bits of GBC */
	#define TLC5971_BYTE24_GBC2_MASK BIT(7)

	/** Bit mask for global brightness control for color 3 in data byte 24, all 7 bits of GBC */
	#define TLC5971_BYTE24_GBC3_MASK GENMASK(6, 0)

	/**
	* @brief create data byte 27 from control data
	*
	* @param control_data control bits
	* @return uint8_t the serialized data byte 27
	*/
	static inline uint8_t tlc5971_data_byte27(uint8_t control_data)
	{
	return FIELD_PREP(TLC5971_BYTE27_WRITE_CMD_MASK, TLC5971_WRITE_COMMAND) \|
	FIELD_PREP(TLC5971_BYTE27_CTRL_MASK, control_data);
	}

	/**
	* @brief create data byte 26 from control data and color 1 GBC
	*
	* @param control_data control bits
	* @param gbc_color_1 global brightness control for color 1 LEDs
	* @return uint8_t the serialized data byte 26
	*/
	static inline uint8_t tlc5971_data_byte26(uint8_t control_data, uint8_t gbc_color_1)
	{
	return FIELD_PREP(TLC5971_BYTE26_CTRL_MASK, control_data) \|
	FIELD_PREP(TLC5971_BYTE26_GBC1_MASK, (gbc_color_1 >> 2));
	}

	/**
	* @brief create data byte 25 from color 1 and 2 GBC
	*
	* @param gbc_color_1 global brightness control for color 1 LEDs
	* @param gbc_color_2 global brightness control for color 2 LEDs
	* @return uint8_t the serialized data byte 25
	*/
	static inline uint8_t tlc5971_data_byte25(uint8_t gbc_color_1, uint8_t gbc_color_2)
	{
	return FIELD_PREP(TLC5971_BYTE25_GBC1_MASK, gbc_color_1) \|
	FIELD_PREP(TLC5971_BYTE25_GBC2_MASK, (gbc_color_2 >> 1));
	}

	/**
	* @brief create data byte 24 from color 2 and 3 GBC
	*
	* @param gbc_color_2 global brightness control for color 2 LEDs
	* @param gbc_color_3 global brightness control for color 3 LEDs
	* @return uint8_t the serialized data byte 24
	*/
	static inline uint8_t tlc5971_data_byte24(uint8_t gbc_color_2, uint8_t gbc_color_3)
	{
	return FIELD_PREP(TLC5971_BYTE24_GBC2_MASK, gbc_color_2) \|
	FIELD_PREP(TLC5971_BYTE24_GBC3_MASK, gbc_color_3);
	}

	/**
	* @brief map user colors to tlc5971 color order
	*
	* @param color_id color id from color mapping
	* @param pixel_data rgb data to be mapped
	* @return the mapped color value
	*/
	static uint8_t tlc5971_map_color(int color_id, const struct led_rgb *pixel_data)
	{
	uint8_t temp = 0;

	switch (color_id) {
	case LED_COLOR_ID_RED:
	temp = pixel_data->r;
	break;
	case LED_COLOR_ID_GREEN:
	temp = pixel_data->g;
	break;
	case LED_COLOR_ID_BLUE:
	temp = pixel_data->b;
	break;
	default:
	temp = 0;
	break;
	}

	return temp;
	}

	/**
	* @brief serialize control data and pixel data for device daisy chain
	*
	* the serializer only supports "full" devices, meaning each device is expected
	* to be mounted with all 4 LEDs.
	*
	* @param dev device pointer
	* @param pixels pixel RGB data for daisy chain
	* @param num_pixels number of pixels in daisy chain
	*/
	static void tlc5971_fill_data_buffer(const struct device dev, struct led_rgb pixels,
	size_t num_pixels)
	{
	const struct tlc5971_config *cfg = dev->config;
	struct tlc5971_data *data = dev->data;
	uint8_t *data_buffer = data->data_buffer;
	int count = 0;

	/*
	* tlc5971 device order is reversed as the rgb data for the last device in the daisy chain
	* should be transmitted first.
	*/
	for (int device = (num_pixels / TLC5971_PIXELS_PER_DEVICE) - 1; device >= 0; device--) {
	/*
	* The SPI frame format expects a BGR color order for the global brightness control
	* values, but since the led_strip API allows custom color mappings, we simply use
	* color_x terms to keep things generic.
	*/
	data_buffer[count++] = tlc5971_data_byte27(data->control_data);
	data_buffer[count++] = tlc5971_data_byte26(data->control_data, data->gbc_color_1);
	data_buffer[count++] = tlc5971_data_byte25(data->gbc_color_1, data->gbc_color_2);
	data_buffer[count++] = tlc5971_data_byte24(data->gbc_color_2, data->gbc_color_3);

	for (int pixel = (TLC5971_PIXELS_PER_DEVICE - 1); pixel >= 0; pixel--) {
	/* data is "reversed" so RGB0 comes last, i.e at byte 0 */
	const struct led_rgb *pixel_data =
	&pixels[(device * TLC5971_PIXELS_PER_DEVICE) + pixel];

	/*
	* Convert pixel data into SPI frames, mapping user colors to tlc5971
	* data frame color order (BGR).
	*/
	for (int color = 0; color < cfg->num_colors; color++) {
	uint8_t temp =
	tlc5971_map_color(cfg->color_mapping[color], pixel_data);

	/*
	* The tlc5971 rgb values are 16 bit but zephyr's rgb values are
	* 8 bit. Simply upscale to 16 bit by using the 8 bit value for both
	* LSB and MSB of the 16 bit word.
	*/
	data_buffer[count++] = temp;
	data_buffer[count++] = temp;
	}
	}
	}
	}

	static int tlc5971_transmit_data(const struct device *dev, size_t num_pixels)
	{
	const struct tlc5971_config *cfg = dev->config;
	struct tlc5971_data *data = dev->data;

	struct spi_buf buf = {
	.buf = data->data_buffer,
	.len = (num_pixels / TLC5971_PIXELS_PER_DEVICE) * TLC5971_PACKET_LEN,
	};

	const struct spi_buf_set tx = {
	.buffers = &buf,
	.count = 1,
	};

	return spi_write_dt(&cfg->bus, &tx);
	}

	static int tlc5971_update_rgb(const struct device dev, struct led_rgb pixels, size_t num_pixels)
	{
	tlc5971_fill_data_buffer(dev, pixels, num_pixels);

	return tlc5971_transmit_data(dev, num_pixels);
	}

	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;
	struct tlc5971_data *data = dev->data;
	int res = -EINVAL;

	if ((pixel.r <= TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX) &&
	(pixel.g <= TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX) &&
	(pixel.b <= TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX)) {
	data->gbc_color_1 = tlc5971_map_color(cfg->color_mapping[0], &pixel);
	data->gbc_color_2 = tlc5971_map_color(cfg->color_mapping[1], &pixel);
	data->gbc_color_3 = tlc5971_map_color(cfg->color_mapping[2], &pixel);
	res = 0;
	}

	return res;
	}

	static int tlc5971_init(const struct device *dev)
	{
	const struct tlc5971_config *cfg = dev->config;
	struct tlc5971_data *data = dev->data;

	if (!spi_is_ready_dt(&cfg->bus)) {
	LOG_ERR("%s: SPI device %s not ready", dev->name, cfg->bus.bus->name);
	return -ENODEV;
	}

	if ((cfg->num_pixels % TLC5971_PIXELS_PER_DEVICE) != 0) {
	LOG_ERR("%s: chain length must be multiple of 4", dev->name);
	return -EINVAL;
	}

	if (cfg->num_colors != TLC5971_NUMBER_OF_COLORS) {
	LOG_ERR("%s: the tlc5971 only supports %i colors", dev->name,
	TLC5971_NUMBER_OF_COLORS);
	return -EINVAL;
	}

	for (int i = 0; i < cfg->num_colors; i++) {
	switch (cfg->color_mapping[i]) {
	case LED_COLOR_ID_RED:
	case LED_COLOR_ID_GREEN:
	case LED_COLOR_ID_BLUE:
	break;
	default:
	LOG_ERR("%s: invalid color mapping", dev->name);
	return -EINVAL;
	}
	}

	/*
	* set up sane defaults for control data.
	* unblanks leds, enables auto display repeat, enables timing resetm uses internal clock for
	* PWM generation and sets the GS reference clock edge select to rising edge
	*/
	data->control_data = TLC5971_BYTE27_CTRL_BIT_OUTTMG \| TLC5971_BYTE26_CTRL_BIT_DSPRPT \|
	TLC5971_BYTE26_CTRL_BIT_TMGRST;

	return 0;
	}

	static const struct led_strip_driver_api tlc5971_api = {
	.update_rgb = tlc5971_update_rgb,
	.length = tlc5971_length,
	};

	#define TLC5971_DATA_BUFFER_LENGTH(inst) \
	(DT_INST_PROP(inst, chain_length) / TLC5971_PIXELS_PER_DEVICE) * TLC5971_PACKET_LEN

	#define TLC5971_DEVICE(inst) \
	static const uint8_t tlc5971_##inst##_color_mapping[] = DT_INST_PROP(inst, color_mapping); \
	static const struct tlc5971_config tlc5971_##inst##_config = { \
	.bus = SPI_DT_SPEC_INST_GET(inst, TLC5971_SPI_OPERATION, 0), \
	.num_pixels = DT_INST_PROP(inst, chain_length), \
	.num_colors = DT_INST_PROP_LEN(inst, color_mapping), \
	.color_mapping = tlc5971_##inst##_color_mapping, \
	}; \
	static uint8_t tlc5971_##inst##_data_buffer[TLC5971_DATA_BUFFER_LENGTH(inst)]; \
	static struct tlc5971_data tlc5971_##inst##_data = { \
	.data_buffer = tlc5971_##inst##_data_buffer, \
	.gbc_color_1 = TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX, \
	.gbc_color_2 = TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX, \
	.gbc_color_3 = TLC5971_GLOBAL_BRIGHTNESS_CONTROL_MAX, \
	}; \
	DEVICE_DT_INST_DEFINE(inst, tlc5971_init, NULL, &tlc5971_##inst##_data, \
	&tlc5971_##inst##_config, POST_KERNEL, \
	CONFIG_LED_STRIP_INIT_PRIORITY, &tlc5971_api);

	DT_INST_FOREACH_STATUS_OKAY(TLC5971_DEVICE)