[PATCH 2/2] drivers/gpio: Port gpio driver to layerscape platform

Scott Wood
2015-11-04T09:17:38Z

On Wed, 2015-11-04 at 09:53 +0100, Arnd Bergmann wrote:
> On Wednesday 04 November 2015 14:48:24 Liu Gang wrote:
> >
> > +static bool gpio_little_endian;
> > +static inline u32 gpio_in32(void __iomem *addr)
> > +{
> > + u32 val;
> > +
> > + if (gpio_little_endian)
> > + val = ioread32(addr);
> > + else
> > + val = ioread32be(addr);
> > +
> > + return val;
> > +}
> > +
> > +static inline void gpio_out32(u32 val, void __iomem *addr)
> > +{
> > + if (gpio_little_endian)
> > + iowrite32(val, addr);
> > + else
> > + iowrite32be(val, addr);
> > +}
>
> I guess this is fixed per architecture, so you could also do this as
>
> static inline void gpio_out32(u32 val, void __iomem *addr)
> {
> if (IS_ENABLED(CONFIG_ARM))
> iowrite32(val, addr);
> else if (IS_ENABLED(CONFIG_PPC)
> iowrite32be(val, addr);
> else
> BUG();
> }

Unfortunately that guess is wrong. Some of our ARM chips have big-endian I/O
and some have little-endian I/O.

-Scott