Re: [PATCH] [POWERPC] mpc5200: Allow for fixed speed MII configurations

[Joakim Tjernlund <joakim.tjernlund@transmode.se>]

On Wed, 2008-04-30 at 08:28 -0600, Grant Likely wrote:
> On Wed, Apr 30, 2008 at 8:16 AM, Joakim Tjernlund
> <joakim.tjernlund@transmode.se> wrote:
> >
> >
> >  On Wed, 2008-04-30 at 07:26 -0600, Grant Likely wrote:
> >  > On Wed, Apr 30, 2008 at 7:10 AM, Joakim Tjernlund
> >  > <joakim.tjernlund@transmode.se> wrote:
> >  > >
> >  > >
> >  > >  On Wed, 2008-04-30 at 07:07 -0600, Grant Likely wrote:
> >  > >  > On Wed, Apr 30, 2008 at 1:36 AM, Joakim Tjernlund
> >  > >  > <joakim.tjernlund@transmode.se> wrote:
> >  > >  > >
> >  > >  > >  On Tue, 2008-04-29 at 17:06 -0600, Grant Likely wrote:
> >  > >  > >  > From: Grant Likely <grant.likely@secretlab.ca>
> >  > >  > >  >
> >  > >  > >  > Various improvements for configuring the MPC5200 MII link from the
> >  > >  > >  > device tree:
> >  > >  > >  > * Look for 'current-speed' property for fixed speed MII links
> >  > >  > >
> >  > >  > >  Not that I have looked, but why can't you use the fixed-link property?
> >  > >  >
> >  > >  > fixed-link seems to be a recent invention, whereas current-speed is
> >  > >  > better know having already been in use with serial devices.  It seemed
> >  > >  > to me to be a better choice, but my opinion can probably be swayed
> >  > >  > (arguments welcome).
> >  > >
> >  > >  yes it is fairly new. You get alot more than just speed: Duplex/Pause
> >  > >  You need these too.
> >  >
> >  > duplex I've got.  pause I don't need.
> >
> >  dunno how you speify Half/Full Duplex, but isn't it possible that
> >  someone else wants to use Pause in the future?
> >  Isn't the point that everyone should use fixed-link when it is there
> >  for this purpose?
> 
> The format of the data is pretty much entirely device dependent (much
> like interrupt and gpio specifiers are controller dependent).  I see
> any need in trying to define a common format for this data since it is
> entirely local to the device.  ie. there is requirement for this data
> to be in the same format for every device.  Also, by not trying to
> lock it down into a common format it gives future devices freedom to
> specify additional flags and parameters in the data.
> 
> so,
> * gianfar:  needs 5 bits of data.
> * 5200 FEC: only needs 2.
> 
> As for 'current-speed' vs. 'fixed-link'.  I just think 'current-speed'
> is the better name.  :-)

Then some day someone else needs Pause or need to control Duplex. Then
you end up with several impl. Maybe fixed-link isn't the best 
name, but it is designed for this purpose.

Anyhow, I not going to argue this more. Seems like I am the
only one thinking it would be better to use fixed-link instead so I 
guess I am wrong here.

 Jocke