Re: [RFC] Addition of kernel

["Enrico Weigelt, metux IT consult" <lkml@xxxxxxxxx>]

On 19.06.19 13:54, Martyn Welch wrote:

Hi,

> But I'm fairly sure some of the lines don't have a sensible
> driver model in which to fit them, specifically I can think of the
> reset, boot mode control and interrupt lines for the GPS unit embedded
> in the device I'm working on.

Looks like a case for rfkill, pm, etc.

> We are also not in the position to make major changes to how
> functionality on this device has already been implemented and whilst we
> are hoping to move to using proper drivers in some places, this is not
> going to be tenable in all cases and we would ideally like to avoid
> utilising a home grown (and certainly unlikely to be upstreamable)
> solution for exposing these GPIOs.

IMHO, the best way for getting things upstream are generic (but
configurable) drivers, or improving existing ones.

If it's just about getting some gpios in a specific state at bootup,
why not doing that in an init script ?

Your description feels a bit like trying to introduce some workarounds
for some not so well designed proprietary legacy code. If your
application directly drives raw gpio's (something I'd do only in really,
exceptionally rare cases), but needs something else to do some tweaks
first, that looks like a broken application. OTOH, I don't think that
applications should do such low level hardware access in the first
place.


--mtx

-- 
Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@xxxxxxxxx -- +49-151-27565287