Re: [PATCH v2 14/15] iio: adc: ad4134: Support high-speed data capture

[Jonathan Cameron]

> Make use of SPI transfer offloading to speed up data capture, enabling data
> acquisition at faster sample rates (up to 1.496 MSPS).
> 
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>

A lot of sashiko feedback so I only took a cursory look.
Please address all that (or point out why it is wrong!)

Jonathan

> diff --git a/drivers/iio/adc/ad4134.c b/drivers/iio/adc/ad4134.c
> index cc6bc325f6ee..94d979c61501 100644
> --- a/drivers/iio/adc/ad4134.c
> +++ b/drivers/iio/adc/ad4134.c


...

> +static int ad4134_offload_setup(struct iio_dev *indio_dev, struct ad4134_state *st)
> +{
> +	struct device *dev = &st->spi->dev;
> +	int ret;
> +
> +	ret = ad4134_pwm_get(st);
> +	if (ret)
> +		return ret;
> +
> +	ret = ad4134_offload_buffer_setup(indio_dev, st->spi);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * Start with a sampling rate slower than 374 kSPS because that is the
> +	 * maximum rate supported with wideband filter (default on power up).
> +	 */
> +	st->odr_hz = 250 * HZ_PER_KHZ;
> +	ret = ad4134_update_conversion_rate(st, st->odr_hz);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to set sampling freq\n");
> +
> +	indio_dev->setup_ops = &ad4134_offload_buffer_setup_ops;
> +	indio_dev->available_scan_masks = ad4134_scan_masks;
> +
> +	switch (st->spi->num_rx_lanes) {
> +	case 1:
> +		return regmap_update_bits(st->regmap, AD4134_DIG_IF_CFG_REG,
> +					  AD4134_DIF_IF_CFG_FORMAT_MASK,
> +					  FIELD_PREP(AD4134_DIF_IF_CFG_FORMAT_MASK,
> +						     AD4134_DATA_FORMAT_SINGLE_CH_MODE));
> +	case 4:
> +		return regmap_update_bits(st->regmap, AD4134_DIG_IF_CFG_REG,
> +					  AD4134_DIF_IF_CFG_FORMAT_MASK,
> +					  FIELD_PREP(AD4134_DIF_IF_CFG_FORMAT_MASK,
> +						     AD4134_DATA_FORMAT_QUAD_CH_PARALLEL));
> +	default:
> +		return dev_err_probe(dev, -EINVAL,
> +			"unsupported number of spi-rx-bus-width elements: %d\n",
> +			st->spi->num_rx_lanes);
> +	}
> +
> +	return 0;

Unreachable code so drop it.

-- 
Jonathan Cameron <jonathan.cameron@xxxxxxxxxxxxxxxx>