Re: [PATCH 3/4] docs: iio: new docs for ad4052 driver

Jonathan Cameron
2025-03-10T19:56:40Z

On Mon, 10 Mar 2025 09:31:45 -0500
David Lechner <dlechner@baylibre.com> wrote:

> On 3/9/25 3:49 PM, Jorge Marques wrote:
> >>> +.. list-table:: Driver attributes
> >>> + :header-rows: 1
> >>> +
> >>> + * - Attribute
> >>> + - Description
> >>> + * - ``in_voltage0_raw``
> >>> + - Raw ADC voltage value
> >>> + * - ``in_voltage0_oversampling_ratio``
> >>> + - Enable the device's burst averaging mode to over sample using
> >>> + the internal sample rate.
> >>> + * - ``in_voltage0_oversampling_ratio_available``
> >>> + - List of available oversampling values. Value 0 disable the burst
> >>> + averaging mode.
> >>> + * - ``sample_rate``
> >>> + - Device internal sample rate used in the burst averaging mode.
> >>> + * - ``sample_rate_available``
> >>> + - List of available sample rates.
> >>
> >> Why not using the standard sampling_frequency[_available] attributes?
> > Because sampling_frequency is the sampling frequency for the pwm trigger
> > during buffer readings.
> > sample_rate is the internal device clock used during monitor and burst
> > averaging modes.
>
> I haven't done a chips with a monitor mode yet where we aren't reading
> the samples, so hopefully Jonathan will chime in here on the usual way
> to handle that.
>
> For the burst averaging mode, I understand the need for a separate attribute
> now. I would suggest to call this the conversion_frequency rather than
> sampling_rate since IIO already defines "sampling" to be the data read
> from the chip to Linux even if it is an averaged value, it still counts
> as one sample.

I should have read on. I'd like this more closely associated with oversampling.
As per other reply we use sampling_frequency in the events directory for
the monitoring frequency case. One of our very first drivers did this
(max1363) so it's been in the ABI a long time!

Jonathan