Re: [libgpiod][RFC] helper functions for basic use cases

[Kent Gibson <warthog618@gmail.com>]

On Tue, May 14, 2024 at 06:31:39AM -0700, Bartosz Golaszewski wrote:
> On Mon, 13 May 2024 12:13:31 +0200, Kent Gibson <warthog618@gmail.com> said:
> >
> >> > /**
> >> >  * @brief Set the bias of requested input line.
> >> >  * @param olr The request to reconfigure.
> >> >  * @param bias The new bias to apply to requested input line.
> >> >  * @return 0 on success, -1 on failure.
> >> >  */
> >> > int gpiod_olr_set_bias(struct gpiod_line_request * olr,
> >> > 		       enum gpiod_line_bias bias);
> >>
> >> For this to work, you'd most likely need a new struct wrapping the request
> >> and also storing the line config. Otherwise - how'd you keep the state of all
> >> the other line settings?
> >>
> >
> > Yeah, I realised that when I went to implement it :(.
> >
> > What I implemented was to read the line info and build the config from that.
> > So no impact on core.
> > Not the most efficient, but for this use case I wan't fussed.
> >
>
> I think those simplified requests should wrap the config structures, otherwise
> we'd have to readback the config from the kernel which would become quite
> complex for anything including more than one line.
>

The whole point of the simplified requests is that they only deal with
a single line.  And the config mutators only deal with a single input.

Wouldn't wrapping break the ability to use all the other
gpiod_line_request_XXX functions, and so require adding more functions
to make use of the simplified requests?

Maybe I'm missing something.

Cheers,
Kent.