Re: [PATCH] pinctrl: msm: allow the gpio base to be configurable

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Mon, Jan 29, 2018 at 1:51 AM, Bjorn Andersson
<bjorn.andersson@xxxxxxxxxx> wrote:

>> > My bad, this should have been -1.
>>
>> Perhaps, but it's been 0 for a very long time, so I don't want to break any
>> existing platforms by suddenly relocating all GPIOs across all Qualcomm
>> platforms.
>>
>
> Yeah, I see that I got this wrong when I wrote the driver 4 years ago...
>
> There should be no in-kernel users depending on these numbers being hard
> coded, so anyone depending on these numbers starting at 0 would be user
> space - doing so incorrectly.

There is a good point in what Tmur is saying here. We never break
userspace, if we can avoid it.

If there is a real problem with setting this base to -1 then I suggest

if (tlmm_has_only_one_instance)
   base = 0;
else
   base = -1;

Especially for an upcoming platform we can start with a clean slate,
it certainly does not have any legacy userspace.

If no problems are detected, let's just use -1.

Yours,
Linus Walleij
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