Re: [PATCH v9 5/8] iio: adc: ad4030: Add SPI offload support

[Andy Shevchenko]

On Mon, Feb 16, 2026 at 12:00:39PM -0300, Marcelo Schmitt wrote:
> AD4030 and similar ADCs can capture data at sample rates up to 2 mega
> samples per second (MSPS). Not all SPI controllers are able to achieve such
> high throughputs and even when the controller is fast enough to run
> transfers at the required speed, it may be costly to the CPU to handle
> transfer data at such high sample rates. Add SPI offload support for AD4030
> and similar ADCs to enable data capture at maximum sample rates.

...

> +	depends on PWM

Seeing this without being mentioned in the commit message is confusing.
Would be nice to add a sentence explaining that "The offload is initiated by
pulses from PWM..." (or in your own words, but make it clear).

...

> +static int ad4030_set_sampling_freq(struct iio_dev *indio_dev, int freq_hz)
> +{
> +	struct ad4030_state *st = iio_priv(indio_dev);
> +
> +	if (!in_range(freq_hz, 1, st->chip->max_sample_rate_hz))

Hmm... Isn't it a off-by-one issue here (because the start == 1)?

Maybe

	if (freq_hz == 0)
		return -EINVAL;

	if (!in_range(freq_hz, 0, st->chip->max_sample_rate_hz))
		return -ERANGE;

> +		return -EINVAL;

?

> +	return ad4030_update_conversion_rate(st, freq_hz, st->avg_log2);
> +}

-- 
With Best Regards,
Andy Shevchenko