Re: [PATCH net-next v1 1/2] dt-bindings: net: dsa: Add KSZ8567 switch support

[Philippe Schenker]

On Tue, 2024-01-23 at 17:23 +0000, Conor Dooley wrote:
> On Tue, Jan 23, 2024 at 05:17:53PM +0100, Philippe Schenker wrote:
> > 
> > 
> > On Tue, 2024-01-23 at 16:06 +0000, Conor Dooley wrote:
> > > On Tue, Jan 23, 2024 at 02:50:13PM +0100, Philippe Schenker
> > > wrote:
> > > > From: Philippe Schenker <philippe.schenker@xxxxxxxxxxxx>
> > > > 
> > > > This commit adds the dt-binding for KSZ8567, a robust 7-port
> > > > Ethernet switch. The KSZ8567 features two RGMII/MII/RMII
> > > > interfaces,
> > > > each capable of gigabit speeds, complemented by five 10/100
> > > > Mbps
> > > > MAC/PHYs.
> > > > 
> > > > Signed-off-by: Philippe Schenker
> > > > <philippe.schenker@xxxxxxxxxxxx>
> > > 
> > > This device has all the same constraints as the other ones in
> > > this
> > > binding, why is it not compatible with any of them? If it isn't,
> > > the
> > > compatible should mention why it is not.
> > 
> > Hi Conor, Thanks for your message!
> > 
> > I need the compatible to make sure the correct ID of the switch is
> > being set in the driver as well as its features.
> 
> Are the features of this switch such that a driver for another ksz
> switch would not work (even in a limited capacity) with the 8567?
> Things like the register map changing or some feature being removed
> are
> examples of why it may not work.

Yes the ksz dsa driver is made so that it checks the ID of the attached
chip and refuses to work if it doesn't match. [1]
It is a very similar chip and uses the same regmap as KSZ9567 but with
lower phy-speeds on its 5 switch ports. The two upstream CPU ports are
gigabit capable. All this information is set-up in the second patch of
this series. [2]

I will include a description to the second series. Thanks for your
feedback.

Philippe


[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/dsa/microchip/ksz_common.c?h=v6.8-rc1#n3181
[2]
https://patchwork.kernel.org/project/netdevbpf/patch/20240123135014.614858-2-dev@xxxxxxxxxxxx/

> 
> > You mean I shall mention the reason in the commit-message, or
> > where?
> 
> Yes.
> 
> Thanks,
> Conor
> 
> > > >  Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml |
> > > > 1 +
> > > >  1 file changed, 1 insertion(+)
> > > > 
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml
> > > > b/Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml
> > > > index c963dc09e8e1..52acc15ebcbf 100644
> > > > ---
> > > > a/Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml
> > > > +++
> > > > b/Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml
> > > > @@ -31,6 +31,7 @@ properties:
> > > >        - microchip,ksz9893
> > > >        - microchip,ksz9563
> > > >        - microchip,ksz8563
> > > > +      - microchip,ksz8567
> > > >  
> > > >    reset-gpios:
> > > >      description:
> > > > -- 
> > > > 2.34.1
> > > >