> > Maybe Documentation/admin-guide/gpio-rpmsg.rst would be better. You should > > also document how to handle features the device does not support. e.g. i > > _think_ > > your hardware supports all 4 interrupt types. But maybe other hardware > > needs to > > return something meaning -EOPNOTSUP? > > > > That should be one type of the error return code in the out field of REPLY > message. > The return code of 0 means success, and the others are error codes.
You need to be careful of architecture code: https://elixir.bootlin.com/linux/v6.17.1/A/ident/EOPNOTSUPP Notice how ENOPNOTSUPP can be 45, 122, 223, or 95. Returning EL2NSYNC or EDQUOT to user space is going to cause confusion... Andrew
