Re: [PATCH v3 3/6] iio: accel: adxl345: Add spi-3wire option

[Jonathan Cameron]

On Sat, 23 Mar 2024 12:20:27 +0000
Lothar Rubusch <l.rubusch@xxxxxxxxx> wrote:

> Add a setup function implementation to the spi module to enable
> spi-3wire as option when specified in the device-tree.
> 
> Signed-off-by: Lothar Rubusch <l.rubusch@xxxxxxxxx>
> ---
>  drivers/iio/accel/adxl345.h     |  3 +++
>  drivers/iio/accel/adxl345_spi.c | 12 +++++++++++-
>  2 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/accel/adxl345.h b/drivers/iio/accel/adxl345.h
> index 3c1ded0c2..6b84a2cee 100644
> --- a/drivers/iio/accel/adxl345.h
> +++ b/drivers/iio/accel/adxl345.h
> @@ -8,6 +8,9 @@
>  #ifndef _ADXL345_H_
>  #define _ADXL345_H_
>  
> +#define ADXL345_REG_DATA_FORMAT		0x31
> +#define ADXL345_DATA_FORMAT_SPI         BIT(6) /* spi-3wire */
Name it that, rather than using a comment.   No need to precisely
match datasheet naming - you are naming the value not the field here.

ADXL345_DATA_FORMAT_SPI_3_WRITE perhaps?

> +
>  /*
>   * In full-resolution mode, scale factor is maintained at ~4 mg/LSB
>   * in all g ranges.
> diff --git a/drivers/iio/accel/adxl345_spi.c b/drivers/iio/accel/adxl345_spi.c
> index 1c0513bd3..1094396ac 100644
> --- a/drivers/iio/accel/adxl345_spi.c
> +++ b/drivers/iio/accel/adxl345_spi.c
> @@ -20,6 +20,16 @@ static const struct regmap_config adxl345_spi_regmap_config = {
>  	.read_flag_mask = BIT(7) | BIT(6),
>  };
>  
> +static int adxl345_spi_setup(struct device *dev, struct regmap *regmap)
> +{
> +	struct spi_device *spi = container_of(dev, struct spi_device, dev);
> +
> +	if (spi->mode & SPI_3WIRE)
> +		return regmap_write(regmap, ADXL345_REG_DATA_FORMAT,
> +			    ADXL345_DATA_FORMAT_SPI);
> +	return 0;
> +}
> +
>  static int adxl345_spi_probe(struct spi_device *spi)
>  {
>  	struct regmap *regmap;
> @@ -33,7 +43,7 @@ static int adxl345_spi_probe(struct spi_device *spi)
>  	if (IS_ERR(regmap))
>  		return dev_err_probe(&spi->dev, PTR_ERR(regmap), "Error initializing regmap\n");
>  
> -	return adxl345_core_probe(&spi->dev, regmap, NULL);
> +	return adxl345_core_probe(&spi->dev, regmap, &adxl345_spi_setup);
>  }
>  
>  static const struct adxl345_chip_info adxl345_spi_info = {