[RFC] iio: light: tcs3472: implementing wait time TODO

[Aldo Conte]

Hi all,

I'd like to resolve the wait time TODO in tcs3472.c.

The TCS3472 has a WTIME register and WEN bit that insert a low-power
wait state between RGBC cycles. The register is already defined in the 
driver but never used.
I noticed that tsl2772.c enables wait with a fixed default and no
userspace control. However, I think exposing the wait time to
userspace would be more useful to tune the power/responsiveness tradeoff.

My plan would be to expose it via an ext_info attribute in
microseconds, following the same convention as integration_time.
Does that sound acceptable, or would you prefer a simpler approach
with just a fixed default like tsl2772?

I also plan a following patch converting the driver to devm.

Thanks,
Aldo