Re: NSLU2 I2C patch

[Piotr Durlej <P.Durlej%stud.elka.pw.edu.pl@localhost>]

On Tue, 24 Jun 2008, Izumi Tsutsui wrote:

> > I believe that the code in nslu2_iic.c is based on the incorrect assumption
> > that setting a bit in the GPIO output enable register configures the
> > corresponding pin as an output.
> >
> > According to the IXP425 documentation from Intel, setting a bit in GPOER
> > configures the relevant pin as an input.
>
> Hmm, I think you are right. I'll commit changes later if no one objects.
>
> > @@ -134,13 +134,18 @@
> >                 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
> >                 if ((reg & GPIO_I2C_SDA_BIT) == 0) {
> >                         reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
> > +                       reg &= ~GPIO_I2C_SDA_BIT;
> > +                       GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
> > +               } else {
> > +                       /* SDA is high; disable SDA output */
> > +                       reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
> >                         reg |= GPIO_I2C_SDA_BIT;
> >                         GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
> >                 }
>
> BTW, is this else clause really needed?
> I think the SDA direction is already input there.
> ---
> Izumi Tsutsui

Yes, SDA is already input at this point, so the else clause is not 
really needed.

Thanks,
Piotr