Re: [RFC PATCH 2/3] pinctrl: imx: add pinmux-imx53 support

From: Lothar WaÃmann
Date: Tue Dec 06 2011 - 02:35:22 EST


Hi,

Shawn Guo writes:
> On Mon, Dec 05, 2011 at 10:18:38PM +0100, Sascha Hauer wrote:
> > Freescale has named the pins after their primary function which is quite
> > confusing.
> >
> > The above means:
> >
> > MX53_PATA_DATA8 -> mux mode 4
> > MX53_PATA_DATA9 -> mux mode 4
> > ...
> >
> > This brings me to the point that currently we have the pins described as
> >
> > #define MX53_PAD_<name>__<function>
> >
> But that's also the reason why we have so many lengthy iomux-mx*.h on
> imx. Taking iomux-mx53.h for example, it's a 109K header with 1219
> LOC, but probably only 10% of the definitions will actually be used.
>
Which has the benefit of having correct pin definitions for everyone
to use. If developers who need to use currently unused pindefs have to
create them on their own, there will always be a good chance in
getting them wrong.

> > which means that you don't have to look into the datasheet to get the
> > different options for a pin
>
> Looking at the datasheet when we write code is a pretty natural thing
> to me.
>
The pindefs are like interrupt numbers or IO addresses for which there
also is a complete list of definitions in the kernel no matter whether
they are actually all in use.


Lothar WaÃmann
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