Re: [PATCH v2 2/3] netdev/of/phy: Add MDIO bus multiplexer support.

[David Daney]

On 09/28/2011 10:32 AM, Michał Mirosław wrote:
> W dniu 28 września 2011 18:51 użytkownik David Daney
> <david.daney@xxxxxxxxxx>  napisał:
> > On 09/28/2011 12:25 AM, Michał Mirosław wrote:
> > > 2011/9/28 David Daney<david.daney@xxxxxxxxxx>:
> > > [...]
> > > > +Example :
> > > > +
> > > > +       /* The parent MDIO bus. */
> > > > +       smi1: mdio@1180000001900 {
> > > > +               compatible = "cavium,octeon-3860-mdio";
> > > > +               #address-cells =<1>;
> > > > +               #size-cells =<0>;
> > > > +               reg =<0x11800 0x00001900 0x0 0x40>;
> > > > +       };
> > > > +
> > > > +       /*
> > > > +          An NXP sn74cbtlv3253 dual 1-of-4 switch controlled by a
> > > > +          pair of GPIO lines.  Child busses 2 and 3 populated with 4
> > > > +          PHYs each.
> > > > +        */
> > > > +       mdio-mux {
> > > > +               compatible = "cavium,mdio-mux-sn74cbtlv3253",
> > > > "cavium,mdio-mux";
> > > > +               gpios =<&gpio1 3 0>,<&gpio1 4 0>;
> > > > +               mdio-parent-bus =<&smi1>;
> > > > +               #address-cells =<1>;
> > > > +               #size-cells =<0>;
> > >
> > > This should probably have 'compatible = "nxp,sn74cbtlv3253";' here.
> >
> > No, the sn74cbtlv3253 is a general purpose part that could be used to
> > multiplex anything (I2C, SPI, random analog signals, etc.).  Only when it is
> > in the "cavium,mdio-mux-sn74cbtlv3253" configuration is it an MDIO bus
> > multiplexer.
>
> This should use some generic name then. 'mdio-mux-gpio' or something.
> There's no point in introducing chip's model for a gate-like discrete
> device.

That could be.  We could define an "mdio-mux-gpio" as something that 
selects the child bus based on the binary encoded value presented on the 
GPIO lines.

I will regenerate the patch set with this in mind.  Note that the only 
part of this patch that will change is this mdio-mux.txt file, no actual 
code is affected.  In patch 3/3 I will add "mdio-mux-gpio" to the 
.of_match_table.

Thanks,
David Daney
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