drivers/mipi_dbi/mipi_dbi_bitbang.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*
  * MIPI DBI Type A and B driver using GPIO
  *
  * Copyright 2024 Stefan Gloor
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 #define DT_DRV_COMPAT zephyr_mipi_dbi_bitbang

 #include <zephyr/drivers/mipi_dbi.h>
 #include <zephyr/drivers/gpio.h>

 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(mipi_dbi_bitbang, CONFIG_MIPI_DBI_LOG_LEVEL);

 /* The MIPI DBI spec allows 8, 9, and 16 bits */
 #define MIPI_DBI_MAX_DATA_BUS_WIDTH 16

 /* Compile in a data bus LUT for improved performance if at least one instance uses an 8-bit bus */
 #define _8_BIT_MODE_PRESENT(n) (DT_INST_PROP_LEN(n, data_gpios) == 8) |
 #define MIPI_DBI_8_BIT_MODE    DT_INST_FOREACH_STATUS_OKAY(_8_BIT_MODE_PRESENT) 0

 struct mipi_dbi_bitbang_config {
 	/* Parallel 8080/6800 data GPIOs */
 	const struct gpio_dt_spec data[MIPI_DBI_MAX_DATA_BUS_WIDTH];
 	const uint8_t data_bus_width;

 	/* Read (type B) GPIO */
 	const struct gpio_dt_spec rd;

 	/* Write (type B) or Read/!Write (type A) GPIO */
 	const struct gpio_dt_spec wr;

 	/* Enable/strobe GPIO (type A) */
 	const struct gpio_dt_spec e;

 	/* Chip-select GPIO */
 	const struct gpio_dt_spec cs;

 	/* Command/Data GPIO */
 	const struct gpio_dt_spec cmd_data;

 	/* Reset GPIO */
 	const struct gpio_dt_spec reset;

 #if MIPI_DBI_8_BIT_MODE
 	/* Data GPIO remap look-up table. Valid if mipi_dbi_bitbang_data.single_port is set */
 	const uint32_t data_lut[256];

 	/* Mask of all data pins. Valid if mipi_dbi_bitbang_data.single_port is set */
 	const uint32_t data_mask;
 #endif
 };

 struct mipi_dbi_bitbang_data {
 	struct k_mutex lock;

 #if MIPI_DBI_8_BIT_MODE
 	/* Indicates whether all data GPIO pins are on the same port and the data LUT is used. */
 	bool single_port;

 	/* Data GPIO port device. Valid if mipi_dbi_bitbang_data.single_port is set */
 	const struct device *data_port;
 #endif
 };

 static inline void mipi_dbi_bitbang_set_data_gpios(const struct mipi_dbi_bitbang_config *config,
 						   struct mipi_dbi_bitbang_data *data,
 						   uint32_t value)
 {
 #if MIPI_DBI_8_BIT_MODE
 	if (data->single_port) {
 		gpio_port_set_masked(data->data_port, config->data_mask, config->data_lut[value]);
 	} else {
 #endif
 		for (int i = 0; i < config->data_bus_width; i++) {
 			gpio_pin_set_dt(&config->data[i], (value & (1 << i)) != 0);
 		}
 #if MIPI_DBI_8_BIT_MODE
 	}
 #endif
 }

 static int mipi_dbi_bitbang_write_helper(const struct device *dev,
 					 const struct mipi_dbi_config *dbi_config, bool cmd_present,
 					 uint8_t cmd, const uint8_t *data_buf, size_t len)
 {
 	const struct mipi_dbi_bitbang_config *config = dev->config;
 	struct mipi_dbi_bitbang_data *data = dev->data;
 	int ret = 0;
 	uint8_t value;

 	ret = k_mutex_lock(&data->lock, K_FOREVER);
 	if (ret < 0) {
 		return ret;
 	}

 	switch (dbi_config->mode) {
 	case MIPI_DBI_MODE_8080_BUS_8_BIT:
 	case MIPI_DBI_MODE_8080_BUS_9_BIT:
 	case MIPI_DBI_MODE_8080_BUS_16_BIT:
 		gpio_pin_set_dt(&config->cs, 1);
 		if (cmd_present) {
 			gpio_pin_set_dt(&config->wr, 0);
 			gpio_pin_set_dt(&config->cmd_data, 0);
 			mipi_dbi_bitbang_set_data_gpios(config, data, cmd);
 			gpio_pin_set_dt(&config->wr, 1);
 		}
 		if (len > 0) {
 			gpio_pin_set_dt(&config->cmd_data, 1);
 			while (len > 0) {
 				value = *(data_buf++);
 				gpio_pin_set_dt(&config->wr, 0);
 				mipi_dbi_bitbang_set_data_gpios(config, data, value);
 				gpio_pin_set_dt(&config->wr, 1);
 				len--;
 			}
 		}
 		gpio_pin_set_dt(&config->cs, 0);
 		break;

 	/* Clocked E mode */
 	case MIPI_DBI_MODE_6800_BUS_8_BIT:
 	case MIPI_DBI_MODE_6800_BUS_9_BIT:
 	case MIPI_DBI_MODE_6800_BUS_16_BIT:
 		gpio_pin_set_dt(&config->cs, 1);
 		gpio_pin_set_dt(&config->wr, 0);
 		if (cmd_present) {
 			gpio_pin_set_dt(&config->e, 1);
 			gpio_pin_set_dt(&config->cmd_data, 0);
 			mipi_dbi_bitbang_set_data_gpios(config, data, cmd);
 			gpio_pin_set_dt(&config->e, 0);
 		}
 		if (len > 0) {
 			gpio_pin_set_dt(&config->cmd_data, 1);
 			while (len > 0) {
 				value = *(data_buf++);
 				gpio_pin_set_dt(&config->e, 1);
 				mipi_dbi_bitbang_set_data_gpios(config, data, value);
 				gpio_pin_set_dt(&config->e, 0);
 				len--;
 			}
 		}
 		gpio_pin_set_dt(&config->cs, 0);
 		break;

 	default:
 		LOG_ERR("MIPI DBI mode %u is not supported.", dbi_config->mode);
 		ret = -ENOTSUP;
 	}

 	k_mutex_unlock(&data->lock);
 	return ret;
 }

 static int mipi_dbi_bitbang_command_write(const struct device *dev,
 					  const struct mipi_dbi_config *dbi_config, uint8_t cmd,
 					  const uint8_t *data_buf, size_t len)
 {
 	return mipi_dbi_bitbang_write_helper(dev, dbi_config, true, cmd, data_buf, len);
 }

 static int mipi_dbi_bitbang_write_display(const struct device *dev,
 					  const struct mipi_dbi_config *dbi_config,
 					  const uint8_t *framebuf,
 					  struct display_buffer_descriptor *desc,
 					  enum display_pixel_format pixfmt)
 {
 	ARG_UNUSED(pixfmt);

 	return mipi_dbi_bitbang_write_helper(dev, dbi_config, false, 0x0, framebuf, desc->buf_size);
 }

 static int mipi_dbi_bitbang_reset(const struct device *dev, k_timeout_t delay)
 {
 	const struct mipi_dbi_bitbang_config *config = dev->config;
 	int ret;

 	LOG_DBG("Performing hw reset.");

 	ret = gpio_pin_set_dt(&config->reset, 1);
 	if (ret < 0) {
 		return ret;
 	}
 	k_sleep(delay);
 	return gpio_pin_set_dt(&config->reset, 0);
 }

 static int mipi_dbi_bitbang_init(const struct device *dev)
 {
 	const struct mipi_dbi_bitbang_config *config = dev->config;
 	const char *failed_pin = NULL;
 	int ret = 0;
 #if MIPI_DBI_8_BIT_MODE
 	struct mipi_dbi_bitbang_data *data = dev->data;
 #endif

 	if (gpio_is_ready_dt(&config->cmd_data)) {
 		ret = gpio_pin_configure_dt(&config->cmd_data, GPIO_OUTPUT_ACTIVE);
 		if (ret < 0) {
 			failed_pin = "cmd_data";
 			goto fail;
 		}
 		gpio_pin_set_dt(&config->cmd_data, 0);
 	}
 	if (gpio_is_ready_dt(&config->rd)) {
 		gpio_pin_configure_dt(&config->rd, GPIO_OUTPUT_ACTIVE);
 		/* Don't emit an error because this pin is unused in type A */
 		gpio_pin_set_dt(&config->rd, 1);
 	}
 	if (gpio_is_ready_dt(&config->wr)) {
 		ret = gpio_pin_configure_dt(&config->wr, GPIO_OUTPUT_ACTIVE);
 		if (ret < 0) {
 			failed_pin = "wr";
 			goto fail;
 		}
 		gpio_pin_set_dt(&config->wr, 1);
 	}
 	if (gpio_is_ready_dt(&config->e)) {
 		gpio_pin_configure_dt(&config->e, GPIO_OUTPUT_ACTIVE);
 		/* Don't emit an error because this pin is unused in type B */
 		gpio_pin_set_dt(&config->e, 0);
 	}
 	if (gpio_is_ready_dt(&config->cs)) {
 		ret = gpio_pin_configure_dt(&config->cs, GPIO_OUTPUT_ACTIVE);
 		if (ret < 0) {
 			failed_pin = "cs";
 			goto fail;
 		}
 		gpio_pin_set_dt(&config->cs, 0);
 	}
 	if (gpio_is_ready_dt(&config->reset)) {
 		ret = gpio_pin_configure_dt(&config->reset, GPIO_OUTPUT_ACTIVE);
 		if (ret < 0) {
 			failed_pin = "reset";
 			goto fail;
 		}
 		gpio_pin_set_dt(&config->reset, 0);
 	}
 	for (int i = 0; i < config->data_bus_width; i++) {
 		if (gpio_is_ready_dt(&config->data[i])) {
 			ret = gpio_pin_configure_dt(&config->data[i], GPIO_OUTPUT_ACTIVE);
 			if (ret < 0) {
 				failed_pin = "data";
 				goto fail;
 			}
 			gpio_pin_set_dt(&config->data[i], 0);
 		}
 	}

 #if MIPI_DBI_8_BIT_MODE
 	/* To optimize performance, we test whether all the data pins are
 	 * on the same port. If they are, we can set the whole port in one go
 	 * instead of setting each pin individually.
 	 * For 8-bit mode only because LUT size grows exponentially.
 	 */
 	if (config->data_bus_width == 8) {
 		data->single_port = true;
 		data->data_port = config->data[0].port;
 		for (int i = 1; i < config->data_bus_width; i++) {
 			if (data->data_port != config->data[i].port) {
 				data->single_port = false;
 			}
 		}
 	}
 	if (data->single_port) {
 		LOG_DBG("LUT optimization enabled. data_mask=0x%x", config->data_mask);
 	}
 #endif

 	return ret;
 fail:
 	LOG_ERR("Failed to configure %s GPIO pin.", failed_pin);
 	return ret;
 }

 static const struct mipi_dbi_driver_api mipi_dbi_bitbang_driver_api = {
 	.reset = mipi_dbi_bitbang_reset,
 	.command_write = mipi_dbi_bitbang_command_write,
 	.write_display = mipi_dbi_bitbang_write_display
 };

 /* This macro is repeatedly called by LISTIFY() at compile-time to generate the data bus LUT */
 #define LUT_GEN(i, n) (((i & (1 << 0)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 0)) : 0) |   \
 		       ((i & (1 << 1)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 1)) : 0) |   \
 		       ((i & (1 << 2)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 2)) : 0) |   \
 		       ((i & (1 << 3)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 3)) : 0) |   \
 		       ((i & (1 << 4)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 4)) : 0) |   \
 		       ((i & (1 << 5)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 5)) : 0) |   \
 		       ((i & (1 << 6)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 6)) : 0) |   \
 		       ((i & (1 << 7)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 7)) : 0))

 /* If at least one instance has an 8-bit bus, add a data look-up table to the read-only config.
  * Whether or not it is valid and actually used for a particular instance is decided at runtime
  * and stored in the instance's mipi_dbi_bitbang_data.single_port.
  */
 #if MIPI_DBI_8_BIT_MODE
 #define DATA_LUT_OPTIMIZATION(n)                                                                   \
 		.data_lut = { LISTIFY(256, LUT_GEN, (,), n) },                                     \
 		.data_mask = ((1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 0)) |                   \
 			      (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 1)) |                   \
 			      (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 2)) |                   \
 			      (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 3)) |                   \
 			      (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 4)) |                   \
 			      (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 5)) |                   \
 			      (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 6)) |                   \
 			      (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 7)))
 #else
 #define DATA_LUT_OPTIMIZATION(n)
 #endif

 #define MIPI_DBI_BITBANG_INIT(n)                                                                   \
 	static const struct mipi_dbi_bitbang_config mipi_dbi_bitbang_config_##n = {                \
 		.data = {GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 0, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 1, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 2, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 3, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 4, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 5, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 6, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 7, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 8, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 9, {0}),                   \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 10, {0}),                  \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 11, {0}),                  \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 12, {0}),                  \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 13, {0}),                  \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 14, {0}),                  \
 			 GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 15, {0})},                 \
 		.data_bus_width = DT_INST_PROP_LEN(n, data_gpios),                                 \
 		.rd = GPIO_DT_SPEC_INST_GET_OR(n, rd_gpios, {}),                                   \
 		.wr = GPIO_DT_SPEC_INST_GET_OR(n, wr_gpios, {}),                                   \
 		.e = GPIO_DT_SPEC_INST_GET_OR(n, e_gpios, {}),                                     \
 		.cs = GPIO_DT_SPEC_INST_GET_OR(n, cs_gpios, {}),                                   \
 		.cmd_data = GPIO_DT_SPEC_INST_GET_OR(n, dc_gpios, {}),                             \
 		.reset = GPIO_DT_SPEC_INST_GET_OR(n, reset_gpios, {}),                             \
 		DATA_LUT_OPTIMIZATION(n)                                                           \
 	};                                                                                         \
 	BUILD_ASSERT(DT_INST_PROP_LEN(n, data_gpios) < MIPI_DBI_MAX_DATA_BUS_WIDTH,                \
 		     "Number of data GPIOs in DT exceeds MIPI_DBI_MAX_DATA_BUS_WIDTH");            \
 	static struct mipi_dbi_bitbang_data mipi_dbi_bitbang_data_##n;                             \
 	DEVICE_DT_INST_DEFINE(n, mipi_dbi_bitbang_init, NULL, &mipi_dbi_bitbang_data_##n,          \
 			      &mipi_dbi_bitbang_config_##n, POST_KERNEL,                           \
 			      CONFIG_MIPI_DBI_INIT_PRIORITY, &mipi_dbi_bitbang_driver_api);

 DT_INST_FOREACH_STATUS_OKAY(MIPI_DBI_BITBANG_INIT)
	/*
	* MIPI DBI Type A and B driver using GPIO
	*
	* Copyright 2024 Stefan Gloor
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	#define DT_DRV_COMPAT zephyr_mipi_dbi_bitbang

	#include <zephyr/drivers/mipi_dbi.h>
	#include <zephyr/drivers/gpio.h>

	#include <zephyr/logging/log.h>
	LOG_MODULE_REGISTER(mipi_dbi_bitbang, CONFIG_MIPI_DBI_LOG_LEVEL);

	/* The MIPI DBI spec allows 8, 9, and 16 bits */
	#define MIPI_DBI_MAX_DATA_BUS_WIDTH 16

	/* Compile in a data bus LUT for improved performance if at least one instance uses an 8-bit bus */
	#define _8_BIT_MODE_PRESENT(n) (DT_INST_PROP_LEN(n, data_gpios) == 8) \|
	#define MIPI_DBI_8_BIT_MODE DT_INST_FOREACH_STATUS_OKAY(_8_BIT_MODE_PRESENT) 0

	struct mipi_dbi_bitbang_config {
	/* Parallel 8080/6800 data GPIOs */
	const struct gpio_dt_spec data[MIPI_DBI_MAX_DATA_BUS_WIDTH];
	const uint8_t data_bus_width;

	/* Read (type B) GPIO */
	const struct gpio_dt_spec rd;

	/* Write (type B) or Read/!Write (type A) GPIO */
	const struct gpio_dt_spec wr;

	/* Enable/strobe GPIO (type A) */
	const struct gpio_dt_spec e;

	/* Chip-select GPIO */
	const struct gpio_dt_spec cs;

	/* Command/Data GPIO */
	const struct gpio_dt_spec cmd_data;

	/* Reset GPIO */
	const struct gpio_dt_spec reset;

	#if MIPI_DBI_8_BIT_MODE
	/* Data GPIO remap look-up table. Valid if mipi_dbi_bitbang_data.single_port is set */
	const uint32_t data_lut[256];

	/* Mask of all data pins. Valid if mipi_dbi_bitbang_data.single_port is set */
	const uint32_t data_mask;
	#endif
	};

	struct mipi_dbi_bitbang_data {
	struct k_mutex lock;

	#if MIPI_DBI_8_BIT_MODE
	/* Indicates whether all data GPIO pins are on the same port and the data LUT is used. */
	bool single_port;

	/* Data GPIO port device. Valid if mipi_dbi_bitbang_data.single_port is set */
	const struct device *data_port;
	#endif
	};

	static inline void mipi_dbi_bitbang_set_data_gpios(const struct mipi_dbi_bitbang_config *config,
	struct mipi_dbi_bitbang_data *data,
	uint32_t value)
	{
	#if MIPI_DBI_8_BIT_MODE
	if (data->single_port) {
	gpio_port_set_masked(data->data_port, config->data_mask, config->data_lut[value]);
	} else {
	#endif
	for (int i = 0; i < config->data_bus_width; i++) {
	gpio_pin_set_dt(&config->data[i], (value & (1 << i)) != 0);
	}
	#if MIPI_DBI_8_BIT_MODE
	}
	#endif
	}

	static int mipi_dbi_bitbang_write_helper(const struct device *dev,
	const struct mipi_dbi_config *dbi_config, bool cmd_present,
	uint8_t cmd, const uint8_t *data_buf, size_t len)
	{
	const struct mipi_dbi_bitbang_config *config = dev->config;
	struct mipi_dbi_bitbang_data *data = dev->data;
	int ret = 0;
	uint8_t value;

	ret = k_mutex_lock(&data->lock, K_FOREVER);
	if (ret < 0) {
	return ret;
	}

	switch (dbi_config->mode) {
	case MIPI_DBI_MODE_8080_BUS_8_BIT:
	case MIPI_DBI_MODE_8080_BUS_9_BIT:
	case MIPI_DBI_MODE_8080_BUS_16_BIT:
	gpio_pin_set_dt(&config->cs, 1);
	if (cmd_present) {
	gpio_pin_set_dt(&config->wr, 0);
	gpio_pin_set_dt(&config->cmd_data, 0);
	mipi_dbi_bitbang_set_data_gpios(config, data, cmd);
	gpio_pin_set_dt(&config->wr, 1);
	}
	if (len > 0) {
	gpio_pin_set_dt(&config->cmd_data, 1);
	while (len > 0) {
	value = *(data_buf++);
	gpio_pin_set_dt(&config->wr, 0);
	mipi_dbi_bitbang_set_data_gpios(config, data, value);
	gpio_pin_set_dt(&config->wr, 1);
	len--;
	}
	}
	gpio_pin_set_dt(&config->cs, 0);
	break;

	/* Clocked E mode */
	case MIPI_DBI_MODE_6800_BUS_8_BIT:
	case MIPI_DBI_MODE_6800_BUS_9_BIT:
	case MIPI_DBI_MODE_6800_BUS_16_BIT:
	gpio_pin_set_dt(&config->cs, 1);
	gpio_pin_set_dt(&config->wr, 0);
	if (cmd_present) {
	gpio_pin_set_dt(&config->e, 1);
	gpio_pin_set_dt(&config->cmd_data, 0);
	mipi_dbi_bitbang_set_data_gpios(config, data, cmd);
	gpio_pin_set_dt(&config->e, 0);
	}
	if (len > 0) {
	gpio_pin_set_dt(&config->cmd_data, 1);
	while (len > 0) {
	value = *(data_buf++);
	gpio_pin_set_dt(&config->e, 1);
	mipi_dbi_bitbang_set_data_gpios(config, data, value);
	gpio_pin_set_dt(&config->e, 0);
	len--;
	}
	}
	gpio_pin_set_dt(&config->cs, 0);
	break;

	default:
	LOG_ERR("MIPI DBI mode %u is not supported.", dbi_config->mode);
	ret = -ENOTSUP;
	}

	k_mutex_unlock(&data->lock);
	return ret;
	}

	static int mipi_dbi_bitbang_command_write(const struct device *dev,
	const struct mipi_dbi_config *dbi_config, uint8_t cmd,
	const uint8_t *data_buf, size_t len)
	{
	return mipi_dbi_bitbang_write_helper(dev, dbi_config, true, cmd, data_buf, len);
	}

	static int mipi_dbi_bitbang_write_display(const struct device *dev,
	const struct mipi_dbi_config *dbi_config,
	const uint8_t *framebuf,
	struct display_buffer_descriptor *desc,
	enum display_pixel_format pixfmt)
	{
	ARG_UNUSED(pixfmt);

	return mipi_dbi_bitbang_write_helper(dev, dbi_config, false, 0x0, framebuf, desc->buf_size);
	}

	static int mipi_dbi_bitbang_reset(const struct device *dev, k_timeout_t delay)
	{
	const struct mipi_dbi_bitbang_config *config = dev->config;
	int ret;

	LOG_DBG("Performing hw reset.");

	ret = gpio_pin_set_dt(&config->reset, 1);
	if (ret < 0) {
	return ret;
	}
	k_sleep(delay);
	return gpio_pin_set_dt(&config->reset, 0);
	}

	static int mipi_dbi_bitbang_init(const struct device *dev)
	{
	const struct mipi_dbi_bitbang_config *config = dev->config;
	const char *failed_pin = NULL;
	int ret = 0;
	#if MIPI_DBI_8_BIT_MODE
	struct mipi_dbi_bitbang_data *data = dev->data;
	#endif

	if (gpio_is_ready_dt(&config->cmd_data)) {
	ret = gpio_pin_configure_dt(&config->cmd_data, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
	failed_pin = "cmd_data";
	goto fail;
	}
	gpio_pin_set_dt(&config->cmd_data, 0);
	}
	if (gpio_is_ready_dt(&config->rd)) {
	gpio_pin_configure_dt(&config->rd, GPIO_OUTPUT_ACTIVE);
	/* Don't emit an error because this pin is unused in type A */
	gpio_pin_set_dt(&config->rd, 1);
	}
	if (gpio_is_ready_dt(&config->wr)) {
	ret = gpio_pin_configure_dt(&config->wr, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
	failed_pin = "wr";
	goto fail;
	}
	gpio_pin_set_dt(&config->wr, 1);
	}
	if (gpio_is_ready_dt(&config->e)) {
	gpio_pin_configure_dt(&config->e, GPIO_OUTPUT_ACTIVE);
	/* Don't emit an error because this pin is unused in type B */
	gpio_pin_set_dt(&config->e, 0);
	}
	if (gpio_is_ready_dt(&config->cs)) {
	ret = gpio_pin_configure_dt(&config->cs, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
	failed_pin = "cs";
	goto fail;
	}
	gpio_pin_set_dt(&config->cs, 0);
	}
	if (gpio_is_ready_dt(&config->reset)) {
	ret = gpio_pin_configure_dt(&config->reset, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
	failed_pin = "reset";
	goto fail;
	}
	gpio_pin_set_dt(&config->reset, 0);
	}
	for (int i = 0; i < config->data_bus_width; i++) {
	if (gpio_is_ready_dt(&config->data[i])) {
	ret = gpio_pin_configure_dt(&config->data[i], GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
	failed_pin = "data";
	goto fail;
	}
	gpio_pin_set_dt(&config->data[i], 0);
	}
	}

	#if MIPI_DBI_8_BIT_MODE
	/* To optimize performance, we test whether all the data pins are
	* on the same port. If they are, we can set the whole port in one go
	* instead of setting each pin individually.
	* For 8-bit mode only because LUT size grows exponentially.
	*/
	if (config->data_bus_width == 8) {
	data->single_port = true;
	data->data_port = config->data[0].port;
	for (int i = 1; i < config->data_bus_width; i++) {
	if (data->data_port != config->data[i].port) {
	data->single_port = false;
	}
	}
	}
	if (data->single_port) {
	LOG_DBG("LUT optimization enabled. data_mask=0x%x", config->data_mask);
	}
	#endif

	return ret;
	fail:
	LOG_ERR("Failed to configure %s GPIO pin.", failed_pin);
	return ret;
	}

	static const struct mipi_dbi_driver_api mipi_dbi_bitbang_driver_api = {
	.reset = mipi_dbi_bitbang_reset,
	.command_write = mipi_dbi_bitbang_command_write,
	.write_display = mipi_dbi_bitbang_write_display
	};

	/* This macro is repeatedly called by LISTIFY() at compile-time to generate the data bus LUT */
	#define LUT_GEN(i, n) (((i & (1 << 0)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 0)) : 0) \| \
	((i & (1 << 1)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 1)) : 0) \| \
	((i & (1 << 2)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 2)) : 0) \| \
	((i & (1 << 3)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 3)) : 0) \| \
	((i & (1 << 4)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 4)) : 0) \| \
	((i & (1 << 5)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 5)) : 0) \| \
	((i & (1 << 6)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 6)) : 0) \| \
	((i & (1 << 7)) ? (1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 7)) : 0))

	/* If at least one instance has an 8-bit bus, add a data look-up table to the read-only config.
	* Whether or not it is valid and actually used for a particular instance is decided at runtime
	* and stored in the instance's mipi_dbi_bitbang_data.single_port.
	*/
	#if MIPI_DBI_8_BIT_MODE
	#define DATA_LUT_OPTIMIZATION(n) \
	.data_lut = { LISTIFY(256, LUT_GEN, (,), n) }, \
	.data_mask = ((1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 0)) \| \
	(1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 1)) \| \
	(1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 2)) \| \
	(1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 3)) \| \
	(1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 4)) \| \
	(1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 5)) \| \
	(1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 6)) \| \
	(1 << DT_INST_GPIO_PIN_BY_IDX(n, data_gpios, 7)))
	#else
	#define DATA_LUT_OPTIMIZATION(n)
	#endif

	#define MIPI_DBI_BITBANG_INIT(n) \
	static const struct mipi_dbi_bitbang_config mipi_dbi_bitbang_config_##n = { \
	.data = {GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 0, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 1, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 2, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 3, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 4, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 5, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 6, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 7, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 8, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 9, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 10, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 11, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 12, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 13, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 14, {0}), \
	GPIO_DT_SPEC_INST_GET_BY_IDX_OR(n, data_gpios, 15, {0})}, \
	.data_bus_width = DT_INST_PROP_LEN(n, data_gpios), \
	.rd = GPIO_DT_SPEC_INST_GET_OR(n, rd_gpios, {}), \
	.wr = GPIO_DT_SPEC_INST_GET_OR(n, wr_gpios, {}), \
	.e = GPIO_DT_SPEC_INST_GET_OR(n, e_gpios, {}), \
	.cs = GPIO_DT_SPEC_INST_GET_OR(n, cs_gpios, {}), \
	.cmd_data = GPIO_DT_SPEC_INST_GET_OR(n, dc_gpios, {}), \
	.reset = GPIO_DT_SPEC_INST_GET_OR(n, reset_gpios, {}), \
	DATA_LUT_OPTIMIZATION(n) \
	}; \
	BUILD_ASSERT(DT_INST_PROP_LEN(n, data_gpios) < MIPI_DBI_MAX_DATA_BUS_WIDTH, \
	"Number of data GPIOs in DT exceeds MIPI_DBI_MAX_DATA_BUS_WIDTH"); \
	static struct mipi_dbi_bitbang_data mipi_dbi_bitbang_data_##n; \
	DEVICE_DT_INST_DEFINE(n, mipi_dbi_bitbang_init, NULL, &mipi_dbi_bitbang_data_##n, \
	&mipi_dbi_bitbang_config_##n, POST_KERNEL, \
	CONFIG_MIPI_DBI_INIT_PRIORITY, &mipi_dbi_bitbang_driver_api);

	DT_INST_FOREACH_STATUS_OKAY(MIPI_DBI_BITBANG_INIT)