Re: [RFC PATCH v1 1/4] iio: types: add IIO_VOLUMEFLOW channel type

[Wadim Mueller]

On Sun, 24 May 2026 14:39:06 -0700
Guenter Roeck <linux@xxxxxxxxxxxx> wrote:

> Two questions: Why restricting to liquid (there are also gas flow sensors),
> and why litres/second and not per minute which seems to be a more common
> unit ?

Both fair points - Jonathan weighed in on the same thread [1],
so summarising for v2:

  1. Liquid vs gas.  Channel type in v2 just says "volumetric
     flow rate" - no "liquid" qualifier.  A liquid-only sensor
     like SLF3S uses it directly, a gas sensor reporting actual
     volumetric flow uses it too.  Standard-volume / density-
     equivalent gas flow is mass flow at heart and will get its
     own IIO_MASSFLOW when a driver needs it, rather than
     overloading IIO_VOLUMEFLOW.

  2. Per second vs per minute.  Going with seconds (l/s, later
     kg/s) because the rest of IIO is SI-based: integration_time,
     sampling_frequency, accel etc. are all per-second.  Drivers
     whose native unit is per-minute fold the 1/60 into _scale,
     same as SLF3S does.

[1] https://lore.kernel.org/all/20260526165950.6ebbf673@jic23-huawei/

Thanks,
Wadim