[libgpiod] Documentation question

[Seamus de Mora <seamusdemora@xxxxxxxxx>]

Hello,

I read a description of libgpiod recently that I cannot find... (my
well-organized reference catalogs have failed me  :) I'm hoping
someone here can help me.

The documentation I read made a point about libgpiod restricting
itself to GPIO; i.e. not I2C, SPI, PWM and a host of other specialized
GPIO interfaces.

I thought it was in the libgpiod README, but it's not. Any ideas on
where I might find this?

Thanks,
~S