RE: bug of gpio transition in pinmux driver

RE: bug of gpio transition in pinmux driver

[Stephen Warren]

Haojian Zhuang wrote at Wednesday, November 23, 2011 6:13 AM:
> Hi Linus & Stephen,
> 
> There's a bug in pinmux driver. We can request gpio via
> pinmux_request_gpio(@gpio). @gpio is the gpio number.
> 
> In pinmux_request_gpio():
>     pin = @gpio - range->base;
>     pin_request(pin);
> 
> This pin is the index of pinctrl_pin_desc[]. What's the definition of
> pinctrl_pin_desc's index? It's the index of PAD, not GPIO. Since the
> goal of pinmux_request_gpio() is to avoid define too much gpio groups.
> We need to add the transition between gpio and pad. It's clear that
> the transition of "pin = @gpio - range->base" can't fit every silicon.

> Especially, one gpio can be routed to two pads in PXA silicon.

That particular case isn't really covered yet; we've been discussing how
to solve that case; see:

https://lkml.org/lkml/2011/11/21/370

-- 
nvpublic

Re: bug of gpio transition in pinmux driver

[Haojian Zhuang]

On Thu, Nov 24, 2011 at 1:13 AM, Stephen Warren <swarren@nvidia.com> wrote:
> Haojian Zhuang wrote at Wednesday, November 23, 2011 6:13 AM:
>> Hi Linus & Stephen,
>>
>> There's a bug in pinmux driver. We can request gpio via
>> pinmux_request_gpio(@gpio). @gpio is the gpio number.
>>
>> In pinmux_request_gpio():
>>     pin = @gpio - range->base;
>>     pin_request(pin);
>>
>> This pin is the index of pinctrl_pin_desc[]. What's the definition of
>> pinctrl_pin_desc's index? It's the index of PAD, not GPIO. Since the
>> goal of pinmux_request_gpio() is to avoid define too much gpio groups.
>> We need to add the transition between gpio and pad. It's clear that
>> the transition of "pin = @gpio - range->base" can't fit every silicon.
>
>> Especially, one gpio can be routed to two pads in PXA silicon.
>
> That particular case isn't really covered yet; we've been discussing how
> to solve that case; see:
>
> https://lkml.org/lkml/2011/11/21/370
>
> --
> nvpublic
>
>

Thanks a lot for your quick reply. If you could cc linux-arm-kernel
mailist for the later discussion of pinmux, it would be better.

Best Regards
Haojian