Re: [PATCH v5 7/7] iio: accel: adxl345: Add spi-3wire option

From: Jonathan Cameron <jic23@kernel.org>
To: Lothar Rubusch <l.rubusch@gmail.com>
Cc: lars@metafoo.de, Michael.Hennerich@analog.com,
	robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
	conor+dt@kernel.org, linux-iio@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	eraretuya@gmail.com
Subject: Re: [PATCH v5 7/7] iio: accel: adxl345: Add spi-3wire option
Date: Thu, 28 Mar 2024 13:39:27 +0000	[thread overview]
Message-ID: <20240328133927.7e49f3bf@jic23-huawei> (raw)
In-Reply-To: <20240327220320.15509-8-l.rubusch@gmail.com>

On Wed, 27 Mar 2024 22:03:20 +0000
Lothar Rubusch <l.rubusch@gmail.com> 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@gmail.com>
> ---
>  drivers/iio/accel/adxl345.h     |  2 ++
>  drivers/iio/accel/adxl345_spi.c | 12 +++++++++++-
>  2 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/accel/adxl345.h b/drivers/iio/accel/adxl345.h
> index 4ea9341d4..e6bc3591c 100644
> --- a/drivers/iio/accel/adxl345.h
> +++ b/drivers/iio/accel/adxl345.h
> @@ -30,6 +30,8 @@
>  #define ADXL345_POWER_CTL_MEASURE	BIT(3)
>  #define ADXL345_POWER_CTL_STANDBY	0x00
>  
> +#define ADXL345_DATA_FORMAT_SPI_3WIRE	BIT(6) /* 3-wire SPI mode */
> +
>  #define ADXL345_DATA_FORMAT_RANGE	GENMASK(1, 0) /* Set the g range */
>  #define ADXL345_DATA_FORMAT_JUSTIFY	BIT(2) /* Left-justified (MSB) mode */
>  #define ADXL345_DATA_FORMAT_FULL_RES	BIT(3) /* Up to 13-bits resolution */
> diff --git a/drivers/iio/accel/adxl345_spi.c b/drivers/iio/accel/adxl345_spi.c
> index 1c0513bd3..f145d5c1d 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_3WIRE);
Your earlier patch carefully (I think) left one or two fields alone, then
this write just comes in and changes them. In particular INT_INVERT.

If it doesn't makes sense to write it there, either write that bit
every time here, or leave it alone every time.  Not decide on whether
to write the bit based on SPI_3WIRE or not.  As far as I know they
are unconnected features.

> +	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 = {