Re: [PATCH v3 07/10] iio: adc: adi-axi-adc: add support for AD7606 register writing

[Jonathan Cameron <jic23@kernel.org>]

> +static int ad7606_bus_reg_read(struct iio_backend *back, u32 reg, u32 *val)
> +{
> +	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
> +	u32 buf;
> +
> +	guard(mutex)(&st->lock);
> +
> +	/*
> +	 * The address is written on the highest weight byte, and the MSB set
> +	 * at 1 indicates a read operation.
> +	 */
> +	buf = FIELD_PREP(ADI_AXI_REG_ADDRESS_MASK, reg) | ADI_AXI_REG_READ_BIT;
> +	axi_adc_raw_write(back, &buf, sizeof(buf));
> +	axi_adc_raw_read(back, val, 4);

sizeof(*val)

> +
> +	/* Write 0x0 on the bus to get back to ADC mode */
> +	buf = 0;
> +	axi_adc_raw_write(back, &buf, sizeof(buf));
> +	return 0;
> +}