text: /* ST Microelectronics IIS3DHHC accelerometer sensor
   *
   * Copyright (c) 2019 STMicroelectronics
   *
   * SPDX-License-Identifier: Apache-2.0
   *
   * Datasheet:
   * https://www.st.com/resource/en/datasheet/iis3dhhc.pdf
   */
  
  #define DT_DRV_COMPAT st_iis3dhhc
  
  #include <string.h>
  #include "iis3dhhc.h"
  #include <logging/log.h>
  
  #if DT_ANY_INST_ON_BUS_STATUS_OKAY(spi)
  
  #define IIS3DHHC_SPI_READ		(1 << 7)
  
  LOG_MODULE_DECLARE(IIS3DHHC, CONFIG_SENSOR_LOG_LEVEL);
  
  static struct spi_config iis3dhhc_spi_conf = {
  	.frequency = DT_INST_PROP(0, spi_max_frequency),
  	.operation = (SPI_OP_MODE_MASTER | SPI_MODE_CPOL |
  		      SPI_MODE_CPHA | SPI_WORD_SET(8) | SPI_LINES_SINGLE),
  	.slave     = DT_INST_REG_ADDR(0),
  	.cs        = NULL,
  };
  
  static int iis3dhhc_spi_read(struct iis3dhhc_data *ctx, uint8_t reg,
  			    uint8_t *data, uint16_t len)
  {
  	struct spi_config *spi_cfg = &iis3dhhc_spi_conf;
  	uint8_t buffer_tx[2] = { reg | IIS3DHHC_SPI_READ, 0 };
  	const struct spi_buf tx_buf = {
  			.buf = buffer_tx,
  			.len = 2,
  	};
  	const struct spi_buf_set tx = {
  		.buffers = &tx_buf,
  		.count = 1
  	};
  	const struct spi_buf rx_buf[2] = {
  		{
  			.buf = NULL,
  			.len = 1,
  		},
  		{
  			.buf = data,
  			.len = len,
  		}
  	};
  	const struct spi_buf_set rx = {
  		.buffers = rx_buf,
  		.count = 2
  	};
  
  	if (spi_transceive(ctx->bus, spi_cfg, &tx, &rx)) {
  		return -EIO;
  	}
  
  	return 0;
  }
  
  static int iis3dhhc_spi_write(struct iis3dhhc_data *ctx, uint8_t reg,
  			     uint8_t *data, uint16_t len)
  {
  	struct spi_config *spi_cfg = &iis3dhhc_spi_conf;
  	uint8_t buffer_tx[1] = { reg & ~IIS3DHHC_SPI_READ };
  	const struct spi_buf tx_buf[2] = {
  		{
  			.buf = buffer_tx,
  			.len = 1,
  		},
  		{
  			.buf = data,
  			.len = len,
  		}
  	};
  	const struct spi_buf_set tx = {
  		.buffers = tx_buf,
  		.count = 2
  	};
  
  
  	if (spi_write(ctx->bus, spi_cfg, &tx)) {
  		return -EIO;
  	}
  
  	return 0;
  }
  
  stmdev_ctx_t iis3dhhc_spi_ctx = {
  	.read_reg = (stmdev_read_ptr) iis3dhhc_spi_read,
  	.write_reg = (stmdev_write_ptr) iis3dhhc_spi_write,
  };
  
  int iis3dhhc_spi_init(struct device *dev)
  {
  	struct iis3dhhc_data *data = dev->driver_data;
  
  	data->ctx = &iis3dhhc_spi_ctx;
  	data->ctx->handle = data;
  
  #if DT_INST_SPI_DEV_HAS_CS_GPIOS(0)
  	/* handle SPI CS thru GPIO if it is the case */
  	data->cs_ctrl.gpio_dev = device_get_binding(
  		DT_INST_SPI_DEV_CS_GPIOS_LABEL(0));
  	if (!data->cs_ctrl.gpio_dev) {
  		LOG_ERR("Unable to get GPIO SPI CS device");
  		return -ENODEV;
  	}
  
  	data->cs_ctrl.gpio_pin = DT_INST_SPI_DEV_CS_GPIOS_PIN(0);
  	data->cs_ctrl.gpio_dt_flags = DT_INST_SPI_DEV_CS_GPIOS_FLAGS(0);
  	data->cs_ctrl.delay = 0U;
  
  	iis3dhhc_spi_conf.cs = &data->cs_ctrl;
  
  	LOG_DBG("SPI GPIO CS configured on %s:%u",
  		    DT_INST_SPI_DEV_CS_GPIOS_LABEL(0),
  		    DT_INST_SPI_DEV_CS_GPIOS_PIN(0));
  #endif
  
  	return 0;
  }
  #endif /* DT_ANY_INST_ON_BUS_STATUS_OKAY(spi) */
  