[PATCH v2 02/21] of: extra: Introduce ofnode_phy_is_fixed_link() API

[Bin Meng]

Hi Vladimir,

On Sat, Mar 13, 2021 at 8:29 PM Vladimir Oltean <olteanv at gmail.com> wrote:
>
> On Sat, Mar 13, 2021 at 02:14:36PM +0200, Vladimir Oltean wrote:
> > On Fri, Mar 12, 2021 at 09:35:43PM +0800, Bin Meng wrote:
> > > Introduce a helper API ofnode_phy_is_fixed_link() to detect whether
> > > the ethernet controller connects to a fixed-link pseudo-PHY device.
> > >
> > > Note there are two ways to describe a fixed PHY attached to an
> > > Ethernet device:
> > >
> > > - the new DT binding, where 'fixed-link' is a sub-node of the
> > >   Ethernet device
> > > - the old DT binding, where 'fixed-link' is a property with 5
> > >   cells encoding various information about the fixed PHY
> > >
> > > Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> > > Reviewed-by: Simon Glass <sjg at chromium.org>
> > > ---
> >
> > I ran a 'grep -r "ofnode_get_property.*fixed-link" .' and saw no in-tree
> > users of the old binding. Why do we bother to be compatible with
> > something which isn't used?
>
> Ah, I see what's going on.
> QEMU fixes up the device tree here:
> https://github.com/qemu/qemu/blob/master/hw/ppc/e500.c#L239
> and adds an old-style fixed-link binding.
> Can't you modify it to add a new-style fixed-link property?

I am afraid that may break guests that haven't supported new-style DT
bindings yet.

> It's not like you didn't have to modify it for the "ranges" property too :)
> https://github.com/qemu/qemu/commit/e5943b00d35efc68ca72ed304cfca98a9f3a647c

Regards,
Bin