Re: [PATCH] gpiolib: Show correct direction from the beginning

[Timur Tabi]

On 9/20/18 5:36 PM, Linus Walleij wrote:
> What I mean is that $SUBJECT patch might not hurt Qualcomms
> GPIOs (not crash the platform) if and only if it is augmented to not
> try to get the initial direction from lines masked off in .valid_mask
> if .need_valid_mask is true.
>
> Whether it makes sense semantically is a different debate, but it
> seems possible to reintroduce calling .get_direction() without
> hurting anyone.

That means that all the logic for checking valid_mask needs to be added 
to the chip driver's .get_direction() function.  We can add that logic 
to msm_gpio_get_direction (at one point, I had a patch that did that, 
but it was rejected).

My concern is: what if a driver depends on a .request call being made 
(in order to configure muxes, for example) before touching the hardware?

I wonder if this is something that really should be handled in the 
driver's .probe function.  The driver should collect that information 
and pass it to add_data.