Re: [PATCH v5 12/16] iio: adc: ad7944: add support for SPI offload

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 15 Nov 2024 14:18:51 -0600
David Lechner <dlechner@baylibre.com> wrote:

> This adds support for SPI offload to the ad7944 driver. This allows
> reading data at the max sample rate of 2.5 MSPS.
> 
> Signed-off-by: David Lechner <dlechner@baylibre.com>
One request for some documentation on the storagebits value.

Otherwise looks good to me.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Note I'm giving tags because it might not all go through my tree +
it's big and complex so they have the advantage I won't read things
again if I've already tagged them (probably!)

Jonathan


> @@ -129,13 +144,33 @@ static const struct ad7944_chip_info _name##_chip_info = {		\
>  		},							\
>  		IIO_CHAN_SOFT_TIMESTAMP(1),				\
>  	},								\
> +	/* basically the same minus soft timestamp plus sampling freq */\
> +	.offload_channels = {						\
> +		{							\
> +			.type = IIO_VOLTAGE,				\
> +			.indexed = 1,					\
> +			.differential = _diff,				\
> +			.channel = 0,					\
> +			.channel2 = _diff ? 1 : 0,			\
> +			.scan_index = 0,				\
> +			.scan_type.sign = _diff ? 's' : 'u',		\
> +			.scan_type.realbits = _bits,			\
> +			.scan_type.storagebits = 32,			\

Add a comment somewhere here on why it jumps up to 32 bits.

> +			.scan_type.endianness = IIO_CPU,		\
> +			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW)	\
> +					| BIT(IIO_CHAN_INFO_SCALE)	\
> +					| BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
> +			.info_mask_separate_available =			\
> +				BIT(IIO_CHAN_INFO_SAMP_FREQ),		\
> +		},							\
> +	},								\
>  }