[PATCH v2] powerpc/gpio: Fix the wrong GPIO input data on MPC8572/MPC8536

[Linus Walleij]

On Fri, Nov 22, 2013 at 9:12 AM, Liu Gang <Gang.Liu at freescale.com> wrote:

> For MPC8572/MPC8536, the status of GPIOs defined as output
> cannot be determined by reading GPDAT register, so the code
> use shadow data register instead. But the code may give the
> wrong status of GPIOs defined as input under some scenarios:
>
> 1. If some pins were configured as inputs and were asserted
> high before booting the kernel, the shadow data has been
> initialized with those pin values.
> 2. Some pins have been configured as output first and have
> been set to the high value, then reconfigured as input.
>
> The above cases will make the shadow data for those input
> pins to be set to high. Then reading the pin status will
> always return high even if the actual pin status is low.
>
> The code should eliminate the effects of the shadow data to
> the input pins, and the status of those pins should be
> read directly from GPDAT.
>
> Signed-off-by: Liu Gang <Gang.Liu at freescale.com>
> ---
> changes in v2:
>  - Added more description of the problem.
>  - Reduced one in_be32() call.
>  - Do not modify the shadow data.

I'm waiting for the maintainers to ACK this before
applying.

Anatolij?

Yours,
Linus Walleij