drivers/adc/adc_ads7052.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /* TI ADS7052 ADC
  *
  * Copyright (c) 2023 Google, LLC
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 #define DT_DRV_COMPAT ti_ads7052

 #include <zephyr/device.h>
 #include <zephyr/drivers/adc.h>
 #include <zephyr/drivers/spi.h>
 #include <zephyr/logging/log.h>
 #include <zephyr/kernel.h>

 LOG_MODULE_REGISTER(adc_ads7052);

 #define ADC_CONTEXT_USES_KERNEL_TIMER
 #include "adc_context.h"

 #define ADS7052_RESOLUTION 14U

 struct ads7052_config {
 	struct spi_dt_spec bus;
 	uint8_t channels;
 };

 struct ads7052_data {
 	struct adc_context ctx;
 	const struct device *dev;
 	uint16_t *buffer;
 	uint16_t *repeat_buffer;
 	uint8_t channels;
 	struct k_thread thread;
 	struct k_sem sem;

 	K_KERNEL_STACK_MEMBER(stack, CONFIG_ADC_ADS7052_ACQUISITION_THREAD_STACK_SIZE);
 };

 static int adc_ads7052_channel_setup(const struct device *dev,
 				     const struct adc_channel_cfg *channel_cfg)
 {
 	const struct ads7052_config *config = dev->config;

 	if (channel_cfg->gain != ADC_GAIN_1) {
 		LOG_ERR("unsupported channel gain '%d'", channel_cfg->gain);
 		return -ENOTSUP;
 	}

 	if (channel_cfg->reference != ADC_REF_VDD_1) {
 		LOG_ERR("unsupported channel reference '%d'", channel_cfg->reference);
 		return -ENOTSUP;
 	}

 	if (channel_cfg->acquisition_time != ADC_ACQ_TIME_DEFAULT) {
 		LOG_ERR("unsupported acquisition_time '%d'", channel_cfg->acquisition_time);
 		return -ENOTSUP;
 	}

 	if (channel_cfg->channel_id >= config->channels) {
 		LOG_ERR("unsupported channel id '%d'", channel_cfg->channel_id);
 		return -ENOTSUP;
 	}
 	return 0;
 }

 static int ads7052_validate_buffer_size(const struct device *dev,
 					const struct adc_sequence *sequence)
 {
 	uint8_t channels = 0;
 	size_t needed;

 	channels = POPCOUNT(sequence->channels);

 	needed = channels * sizeof(uint16_t);
 	if (sequence->options) {
 		needed *= (1 + sequence->options->extra_samplings);
 	}

 	if (sequence->buffer_size < needed) {
 		return -ENOMEM;
 	}

 	return 0;
 }

 /**
  * @brief Send ADS7052 Offset calibration request
  *
  * On power-up, the host must provide 24 SCLKs in the first serial transfer to enter the OFFCAL
  * state. During normal operation, the host must provide 64 SCLKs in the serial transfer frame to
  * enter the OFFCAL state.
  */
 static int ads7052_send_calibration(const struct device *dev, bool power_up)
 {
 	const struct ads7052_config *config = dev->config;
 	int err;
 	uint8_t sclks_needed = power_up ? 24 : 64;
 	uint8_t num_bytes = sclks_needed / 8;
 	uint8_t tx_bytes[8] = {0};

 	const struct spi_buf tx_buf = {.buf = tx_bytes, .len = num_bytes};
 	const struct spi_buf_set tx = {.buffers = &tx_buf, .count = 1};

 	err = spi_write_dt(&config->bus, &tx);

 	return err;
 }

 static int ads7052_start_read(const struct device *dev, const struct adc_sequence *sequence)
 {
 	const struct ads7052_config *config = dev->config;
 	struct ads7052_data *data = dev->data;
 	int err;

 	if (sequence->resolution != ADS7052_RESOLUTION) {
 		LOG_ERR("unsupported resolution %d", sequence->resolution);
 		return -ENOTSUP;
 	}

 	if (find_msb_set(sequence->channels) > config->channels) {
 		LOG_ERR("unsupported channels in mask: 0x%08x", sequence->channels);
 		return -ENOTSUP;
 	}

 	if (sequence->calibrate) {
 		ads7052_send_calibration(dev, false);
 	}

 	err = ads7052_validate_buffer_size(dev, sequence);
 	if (err) {
 		LOG_ERR("buffer size too small");
 		return err;
 	}

 	data->buffer = sequence->buffer;
 	adc_context_start_read(&data->ctx, sequence);

 	return adc_context_wait_for_completion(&data->ctx);
 }

 static int adc_ads7052_read_async(const struct device *dev, const struct adc_sequence *sequence,
 				  struct k_poll_signal *async)
 {
 	struct ads7052_data *data = dev->data;
 	int error;

 	adc_context_lock(&data->ctx, async ? true : false, async);
 	error = ads7052_start_read(dev, sequence);
 	adc_context_release(&data->ctx, error);

 	return error;
 }

 static int adc_ads7052_read(const struct device *dev, const struct adc_sequence *sequence)
 {
 	return adc_ads7052_read_async(dev, sequence, NULL);
 }

 static void adc_context_start_sampling(struct adc_context *ctx)
 {
 	struct ads7052_data *data = CONTAINER_OF(ctx, struct ads7052_data, ctx);

 	data->channels = ctx->sequence.channels;
 	data->repeat_buffer = data->buffer;

 	k_sem_give(&data->sem);
 }

 static void adc_context_update_buffer_pointer(struct adc_context *ctx, bool repeat_sampling)
 {
 	struct ads7052_data *data = CONTAINER_OF(ctx, struct ads7052_data, ctx);

 	if (repeat_sampling) {
 		data->buffer = data->repeat_buffer;
 	}
 }

 /**
  *  @brief Get a 14-bit integer from raw ADC data.
  *
  *  @param src Location of the big-endian 14-bit integer to get.
  *
  *  @return 14-bit integer in host endianness.
  */
 static inline int ads7052_get_be14(const uint8_t src[2])
 {
 	return ((src[0] & 0x7F) << 7) | (src[1] >> 1);
 }

 /**
  * @brief Read ADS7052 over SPI interface
  *
  * A leading 0 is output on the SDO pin on the CS falling edge.
  * The most significant bit (MSB) of the output data is launched on the SDO pin on the rising edge
  * after the first SCLK falling edge. Subsequent output bits are launched on the subsequent rising
  * edges provided on SCLK. When all 14 output bits are shifted out, the device outputs 0's on the
  * subsequent SCLK rising edges. The device enters the ACQ state after 18 clocks and a minimum time
  * of tACQ must be provided for acquiring the next sample. If the device is provided with less than
  * 18 SCLK falling edges in the present serial transfer frame, the device provides an invalid
  * conversion result in the next serial transfer frame
  */
 static int ads7052_read_channel(const struct device *dev, uint8_t channel, uint16_t *result)
 {
 	const struct ads7052_config *config = dev->config;
 	int err;
 	uint8_t rx_bytes[3];
 	const struct spi_buf rx_buf[1] = {{.buf = rx_bytes, .len = sizeof(rx_bytes)}};
 	const struct spi_buf_set rx = {.buffers = rx_buf, .count = ARRAY_SIZE(rx_buf)};

 	err = spi_read_dt(&config->bus, &rx);
 	if (err) {
 		return err;
 	}

 	*result = ads7052_get_be14(rx_bytes);
 	*result &= BIT_MASK(ADS7052_RESOLUTION);

 	return 0;
 }

 static void ads7052_acquisition_thread(struct ads7052_data *data)
 {
 	uint16_t result = 0;
 	uint8_t channel;
 	int err = 0;

 	err = ads7052_send_calibration(data->dev, true);
 	if (err) {
 		LOG_ERR("failed to send powerup sequence (err %d)", err);
 	}

 	while (true) {
 		k_sem_take(&data->sem, K_FOREVER);

 		while (data->channels != 0) {
 			channel = find_lsb_set(data->channels) - 1;

 			LOG_DBG("reading channel %d", channel);

 			err = ads7052_read_channel(data->dev, channel, &result);
 			if (err) {
 				LOG_ERR("failed to read channel %d (err %d)", channel, err);
 				adc_context_complete(&data->ctx, err);
 				break;
 			}

 			LOG_DBG("read channel %d, result = %d", channel, result);

 			*data->buffer++ = result;
 			WRITE_BIT(data->channels, channel, 0);
 		}

 		adc_context_on_sampling_done(&data->ctx, data->dev);
 	}
 }

 static int adc_ads7052_init(const struct device *dev)
 {
 	const struct ads7052_config *config = dev->config;
 	struct ads7052_data *data = dev->data;

 	data->dev = dev;

 	adc_context_init(&data->ctx);
 	k_sem_init(&data->sem, 0, 1);

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

 	k_thread_create(&data->thread, data->stack,
 			CONFIG_ADC_ADS7052_ACQUISITION_THREAD_STACK_SIZE,
 			(k_thread_entry_t)ads7052_acquisition_thread, data, NULL, NULL,
 			CONFIG_ADC_ADS7052_ACQUISITION_THREAD_PRIO, 0, K_NO_WAIT);

 	adc_context_unlock_unconditionally(&data->ctx);

 	return 0;
 }

 static const struct adc_driver_api ads7052_api = {
 	.channel_setup = adc_ads7052_channel_setup,
 	.read = adc_ads7052_read,
 #ifdef CONFIG_ADC_ASYNC
 	.read_async = adc_ads7052_read_async,
 #endif
 };

 #define ADC_ADS7052_SPI_CFG \
 	SPI_OP_MODE_MASTER | SPI_MODE_CPOL | SPI_MODE_CPHA | SPI_WORD_SET(8) | SPI_TRANSFER_MSB

 #define ADC_ADS7052_INIT(n)                                                                        \
                                                                                                    \
 	static const struct ads7052_config ads7052_cfg_##n = {                                     \
 		.bus = SPI_DT_SPEC_INST_GET(n, ADC_ADS7052_SPI_CFG, 1U),                           \
 		.channels = 1,                                                                     \
 	};                                                                                         \
                                                                                                    \
 	static struct ads7052_data ads7052_data_##n = {                                            \
 		ADC_CONTEXT_INIT_TIMER(ads7052_data_##n, ctx),                                     \
 		ADC_CONTEXT_INIT_LOCK(ads7052_data_##n, ctx),                                      \
 		ADC_CONTEXT_INIT_SYNC(ads7052_data_##n, ctx),                                      \
 	};                                                                                         \
                                                                                                    \
 	DEVICE_DT_INST_DEFINE(n, adc_ads7052_init, NULL, &ads7052_data_##n, &ads7052_cfg_##n,      \
 			      POST_KERNEL, CONFIG_ADC_ADS7052_INIT_PRIORITY, &ads7052_api);

 DT_INST_FOREACH_STATUS_OKAY(ADC_ADS7052_INIT)
	/* TI ADS7052 ADC
	*
	* Copyright (c) 2023 Google, LLC
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	#define DT_DRV_COMPAT ti_ads7052

	#include <zephyr/device.h>
	#include <zephyr/drivers/adc.h>
	#include <zephyr/drivers/spi.h>
	#include <zephyr/logging/log.h>
	#include <zephyr/kernel.h>

	LOG_MODULE_REGISTER(adc_ads7052);

	#define ADC_CONTEXT_USES_KERNEL_TIMER
	#include "adc_context.h"

	#define ADS7052_RESOLUTION 14U

	struct ads7052_config {
	struct spi_dt_spec bus;
	uint8_t channels;
	};

	struct ads7052_data {
	struct adc_context ctx;
	const struct device *dev;
	uint16_t *buffer;
	uint16_t *repeat_buffer;
	uint8_t channels;
	struct k_thread thread;
	struct k_sem sem;

	K_KERNEL_STACK_MEMBER(stack, CONFIG_ADC_ADS7052_ACQUISITION_THREAD_STACK_SIZE);
	};

	static int adc_ads7052_channel_setup(const struct device *dev,
	const struct adc_channel_cfg *channel_cfg)
	{
	const struct ads7052_config *config = dev->config;

	if (channel_cfg->gain != ADC_GAIN_1) {
	LOG_ERR("unsupported channel gain '%d'", channel_cfg->gain);
	return -ENOTSUP;
	}

	if (channel_cfg->reference != ADC_REF_VDD_1) {
	LOG_ERR("unsupported channel reference '%d'", channel_cfg->reference);
	return -ENOTSUP;
	}

	if (channel_cfg->acquisition_time != ADC_ACQ_TIME_DEFAULT) {
	LOG_ERR("unsupported acquisition_time '%d'", channel_cfg->acquisition_time);
	return -ENOTSUP;
	}

	if (channel_cfg->channel_id >= config->channels) {
	LOG_ERR("unsupported channel id '%d'", channel_cfg->channel_id);
	return -ENOTSUP;
	}
	return 0;
	}

	static int ads7052_validate_buffer_size(const struct device *dev,
	const struct adc_sequence *sequence)
	{
	uint8_t channels = 0;
	size_t needed;

	channels = POPCOUNT(sequence->channels);

	needed = channels * sizeof(uint16_t);
	if (sequence->options) {
	needed *= (1 + sequence->options->extra_samplings);
	}

	if (sequence->buffer_size < needed) {
	return -ENOMEM;
	}

	return 0;
	}

	/**
	* @brief Send ADS7052 Offset calibration request
	*
	* On power-up, the host must provide 24 SCLKs in the first serial transfer to enter the OFFCAL
	* state. During normal operation, the host must provide 64 SCLKs in the serial transfer frame to
	* enter the OFFCAL state.
	*/
	static int ads7052_send_calibration(const struct device *dev, bool power_up)
	{
	const struct ads7052_config *config = dev->config;
	int err;
	uint8_t sclks_needed = power_up ? 24 : 64;
	uint8_t num_bytes = sclks_needed / 8;
	uint8_t tx_bytes[8] = {0};

	const struct spi_buf tx_buf = {.buf = tx_bytes, .len = num_bytes};
	const struct spi_buf_set tx = {.buffers = &tx_buf, .count = 1};

	err = spi_write_dt(&config->bus, &tx);

	return err;
	}

	static int ads7052_start_read(const struct device dev, const struct adc_sequence sequence)
	{
	const struct ads7052_config *config = dev->config;
	struct ads7052_data *data = dev->data;
	int err;

	if (sequence->resolution != ADS7052_RESOLUTION) {
	LOG_ERR("unsupported resolution %d", sequence->resolution);
	return -ENOTSUP;
	}

	if (find_msb_set(sequence->channels) > config->channels) {
	LOG_ERR("unsupported channels in mask: 0x%08x", sequence->channels);
	return -ENOTSUP;
	}

	if (sequence->calibrate) {
	ads7052_send_calibration(dev, false);
	}

	err = ads7052_validate_buffer_size(dev, sequence);
	if (err) {
	LOG_ERR("buffer size too small");
	return err;
	}

	data->buffer = sequence->buffer;
	adc_context_start_read(&data->ctx, sequence);

	return adc_context_wait_for_completion(&data->ctx);
	}

	static int adc_ads7052_read_async(const struct device dev, const struct adc_sequence sequence,
	struct k_poll_signal *async)
	{
	struct ads7052_data *data = dev->data;
	int error;

	adc_context_lock(&data->ctx, async ? true : false, async);
	error = ads7052_start_read(dev, sequence);
	adc_context_release(&data->ctx, error);

	return error;
	}

	static int adc_ads7052_read(const struct device dev, const struct adc_sequence sequence)
	{
	return adc_ads7052_read_async(dev, sequence, NULL);
	}

	static void adc_context_start_sampling(struct adc_context *ctx)
	{
	struct ads7052_data *data = CONTAINER_OF(ctx, struct ads7052_data, ctx);

	data->channels = ctx->sequence.channels;
	data->repeat_buffer = data->buffer;

	k_sem_give(&data->sem);
	}

	static void adc_context_update_buffer_pointer(struct adc_context *ctx, bool repeat_sampling)
	{
	struct ads7052_data *data = CONTAINER_OF(ctx, struct ads7052_data, ctx);

	if (repeat_sampling) {
	data->buffer = data->repeat_buffer;
	}
	}

	/**
	* @brief Get a 14-bit integer from raw ADC data.
	*
	* @param src Location of the big-endian 14-bit integer to get.
	*
	* @return 14-bit integer in host endianness.
	*/
	static inline int ads7052_get_be14(const uint8_t src[2])
	{
	return ((src[0] & 0x7F) << 7) \| (src[1] >> 1);
	}

	/**
	* @brief Read ADS7052 over SPI interface
	*
	* A leading 0 is output on the SDO pin on the CS falling edge.
	* The most significant bit (MSB) of the output data is launched on the SDO pin on the rising edge
	* after the first SCLK falling edge. Subsequent output bits are launched on the subsequent rising
	* edges provided on SCLK. When all 14 output bits are shifted out, the device outputs 0's on the
	* subsequent SCLK rising edges. The device enters the ACQ state after 18 clocks and a minimum time
	* of tACQ must be provided for acquiring the next sample. If the device is provided with less than
	* 18 SCLK falling edges in the present serial transfer frame, the device provides an invalid
	* conversion result in the next serial transfer frame
	*/
	static int ads7052_read_channel(const struct device dev, uint8_t channel, uint16_t result)
	{
	const struct ads7052_config *config = dev->config;
	int err;
	uint8_t rx_bytes[3];
	const struct spi_buf rx_buf[1] = {{.buf = rx_bytes, .len = sizeof(rx_bytes)}};
	const struct spi_buf_set rx = {.buffers = rx_buf, .count = ARRAY_SIZE(rx_buf)};

	err = spi_read_dt(&config->bus, &rx);
	if (err) {
	return err;
	}

	*result = ads7052_get_be14(rx_bytes);
	*result &= BIT_MASK(ADS7052_RESOLUTION);

	return 0;
	}

	static void ads7052_acquisition_thread(struct ads7052_data *data)
	{
	uint16_t result = 0;
	uint8_t channel;
	int err = 0;

	err = ads7052_send_calibration(data->dev, true);
	if (err) {
	LOG_ERR("failed to send powerup sequence (err %d)", err);
	}

	while (true) {
	k_sem_take(&data->sem, K_FOREVER);

	while (data->channels != 0) {
	channel = find_lsb_set(data->channels) - 1;

	LOG_DBG("reading channel %d", channel);

	err = ads7052_read_channel(data->dev, channel, &result);
	if (err) {
	LOG_ERR("failed to read channel %d (err %d)", channel, err);
	adc_context_complete(&data->ctx, err);
	break;
	}

	LOG_DBG("read channel %d, result = %d", channel, result);

	*data->buffer++ = result;
	WRITE_BIT(data->channels, channel, 0);
	}

	adc_context_on_sampling_done(&data->ctx, data->dev);
	}
	}

	static int adc_ads7052_init(const struct device *dev)
	{
	const struct ads7052_config *config = dev->config;
	struct ads7052_data *data = dev->data;

	data->dev = dev;

	adc_context_init(&data->ctx);
	k_sem_init(&data->sem, 0, 1);

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

	k_thread_create(&data->thread, data->stack,
	CONFIG_ADC_ADS7052_ACQUISITION_THREAD_STACK_SIZE,
	(k_thread_entry_t)ads7052_acquisition_thread, data, NULL, NULL,
	CONFIG_ADC_ADS7052_ACQUISITION_THREAD_PRIO, 0, K_NO_WAIT);

	adc_context_unlock_unconditionally(&data->ctx);

	return 0;
	}

	static const struct adc_driver_api ads7052_api = {
	.channel_setup = adc_ads7052_channel_setup,
	.read = adc_ads7052_read,
	#ifdef CONFIG_ADC_ASYNC
	.read_async = adc_ads7052_read_async,
	#endif
	};

	#define ADC_ADS7052_SPI_CFG \
	SPI_OP_MODE_MASTER \| SPI_MODE_CPOL \| SPI_MODE_CPHA \| SPI_WORD_SET(8) \| SPI_TRANSFER_MSB

	#define ADC_ADS7052_INIT(n) \
	\
	static const struct ads7052_config ads7052_cfg_##n = { \
	.bus = SPI_DT_SPEC_INST_GET(n, ADC_ADS7052_SPI_CFG, 1U), \
	.channels = 1, \
	}; \
	\
	static struct ads7052_data ads7052_data_##n = { \
	ADC_CONTEXT_INIT_TIMER(ads7052_data_##n, ctx), \
	ADC_CONTEXT_INIT_LOCK(ads7052_data_##n, ctx), \
	ADC_CONTEXT_INIT_SYNC(ads7052_data_##n, ctx), \
	}; \
	\
	DEVICE_DT_INST_DEFINE(n, adc_ads7052_init, NULL, &ads7052_data_##n, &ads7052_cfg_##n, \
	POST_KERNEL, CONFIG_ADC_ADS7052_INIT_PRIORITY, &ads7052_api);

	DT_INST_FOREACH_STATUS_OKAY(ADC_ADS7052_INIT)