[U-Boot] GPIO driver for Freescale QorIQ T2080

[Mario Six]

On Wed, May 11, 2016 at 3:21 PM, Joakim Tjernlund <
Joakim.Tjernlund at infinera.com> wrote:

> On Wed, 2016-05-11 at 11:54 +0200, Mario Six wrote:
> > On Tue, May 10, 2016 at 1:22 AM, Hamish Martin <
> > Hamish.Martin at alliedtelesis.co.nz> wrote:
> >
> > >
> > > Hi,
> > >
> > > I'm looking for uboot driver support for the Freescale QorIQ T2080 CPU.
> > > This has 4 blocks of GPIOs similar to the single block defined in
> > > arch/powerpc/include/asm/mpc85xx_gpio.h.
> > >
> > > If someone is working on a driver for that CPU or similar, let me know.
> > > Ideally this would fit the new driver model. I'd be happy to help test
> > > it out and debug it.
> > >
> > > Alternatively, if you know another way to drive those GPIO blocks with
> > > existing code, feel free to suggest a way.
> > >
> > > Cheers,
> > > Hamish Martin.
> > >
> > Hi Hamish,
> >
> > I posted v2 of a patch series for a MPC85xx GPIO DM driver just
> yesterday;
> > it was
> > tested on a P1022, but it's quite likely that it will work with other
> > QorIQs,
> > too (it's basically arpc/powerpc/include/asm/mpc85xx_gpio.h turned into a
> > proper DM driver).
>
> I have not read you patch but I wanted to mention a defect in QorIO:
> It cannot read back the DAT register, it always read the pin values.
> This means one needs to hold the DAT register in a RAM copy or risk
> malfunction when using open drain etc.
>
> See GPIO for QorIO in the kernel for details.
>
>  Jocke


I didn't know of that issue; thanks for the heads-up! I'll implement
shadowing
for the DAT register in v3 (especially since I'm also enabling open drain
functionality in the series).

Best regards,
Mario