[PATCH] dt: Document a compatible entry for MDIO ethernet Phys

[PATCH] dt: Document a compatible entry for MDIO ethernet Phys

[Jason Gunthorpe]

This describes a compatible entry of the form:
  ethernet-phy-idAAAA,BBBB
Which is modelled after the PCI structured compatible entry
(pciVVVV,DDDD.SSSS.ssss.RR)

If present the OF core will be able to use this information to
directly create the correct phy without auto probing the bus.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
---
 Documentation/devicetree/bindings/net/phy.txt | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Patch to parse this compatible string to follow if this binding is
acceptable.

Please see

http://www.spinics.net/lists/devicetree/msg13175.html

For discussion and a conceptual parsing patch.

diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
index 7cd18fb..d70b535 100644
--- a/Documentation/devicetree/bindings/net/phy.txt
+++ b/Documentation/devicetree/bindings/net/phy.txt
@@ -23,10 +23,18 @@ Optional Properties:
   assume clause 22. The compatible list may also contain other
   elements.
 
+  If the phy's identifier is known then the list may contain an entry
+  of the form: "ethernet-phy-idAAAA,BBBB" where
+     AAAA - The value of the 16 bit Phy Identifier 1 register as
+            4 hex digits. This is the chip vendor OUI bits 3:18
+     BBBB - The value of the 16 bit Phy Identifier 2 register as
+            4 hex digits. This is the chip vendor OUI bits 19:24,
+            followed by 10 bits of a vendor specific ID.
+
 Example:
 
 ethernet-phy@0 {
-	compatible = "ethernet-phy-ieee802.3-c22";
+	compatible = "ethernet-phy-id0141,0e90", "ethernet-phy-ieee802.3-c22";
 	linux,phandle = <2452000>;
 	interrupt-parent = <40000>;
 	interrupts = <35 1>;
-- 
1.8.1.2

Re: [PATCH] dt: Document a compatible entry for MDIO ethernet Phys

[Rob Herring]

On Tue, Dec 10, 2013 at 1:39 PM, Jason Gunthorpe
<jgunthorpe@obsidianresearch.com> wrote:
> This describes a compatible entry of the form:
>   ethernet-phy-idAAAA,BBBB
> Which is modelled after the PCI structured compatible entry
> (pciVVVV,DDDD.SSSS.ssss.RR)
>
> If present the OF core will be able to use this information to
> directly create the correct phy without auto probing the bus.
>
> Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
> ---
>  Documentation/devicetree/bindings/net/phy.txt | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> Patch to parse this compatible string to follow if this binding is
> acceptable.

One minor comment below, otherwise:

Acked-by: Rob Herring <robh@kernel.org>

> Please see
>
> http://www.spinics.net/lists/devicetree/msg13175.html
>
> For discussion and a conceptual parsing patch.
>
> diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
> index 7cd18fb..d70b535 100644
> --- a/Documentation/devicetree/bindings/net/phy.txt
> +++ b/Documentation/devicetree/bindings/net/phy.txt
> @@ -23,10 +23,18 @@ Optional Properties:
>    assume clause 22. The compatible list may also contain other
>    elements.
>
> +  If the phy's identifier is known then the list may contain an entry
> +  of the form: "ethernet-phy-idAAAA,BBBB" where

I think this should be a period rather than a comma as we are not
separating a vendor ID from product ID.

Rob

Re: [PATCH] dt: Document a compatible entry for MDIO ethernet Phys

[Jason Gunthorpe]

On Wed, Jan 08, 2014 at 12:37:03PM -0600, Rob Herring wrote:

> > Patch to parse this compatible string to follow if this binding is
> > acceptable.
> 
> One minor comment below, otherwise:
> 
> Acked-by: Rob Herring <robh@kernel.org>

K, I'll send a series hopefully in a few weeks after some travel.
 
> > +  If the phy's identifier is known then the list may contain an entry
> > +  of the form: "ethernet-phy-idAAAA,BBBB" where
> 
> I think this should be a period rather than a comma as we are not
> separating a vendor ID from product ID.

OK, that makes sense.

Inspecting further, the format of the 32 bit AAAABBBB is actually
broken out into:
  OUI[3:18] || OUI[19:24] || MODEL[5:0] || REV[3:0]

So a possible choice with the 'vendor ID,product ID' split is:
  ethernet-phyOOOOO,MM.R

xlate is:

AAAABBBB = ((OOOOO >> 6) << 16) |
           ((OOOOO & 0x3f) << 10) |
           (MM << 4) |
      	   R

Which doesn't textually match the register value, or any other
phy ID constants in the kernel, however makes more sense from the
'vendor ID,product ID' angle.

Eg a Marvell 88E1310 would encode into the two options as:
  ethernet-phy05043,29.0
  ethernet-phy-id0141.0e90

And the kernel has constants like this:
include/linux/marvell_phy.h:#define MARVELL_PHY_ID_88E1318S 0x01410e90

In light of this detail do you still like 'ethernet-phy-id0141.0e90' ?

Thanks,
Jason

Re: [PATCH] dt: Document a compatible entry for MDIO ethernet Phys

[Rob Herring]

On Wed, Jan 8, 2014 at 3:16 PM, Jason Gunthorpe
<jgunthorpe@obsidianresearch.com> wrote:
> On Wed, Jan 08, 2014 at 12:37:03PM -0600, Rob Herring wrote:
>
>> > Patch to parse this compatible string to follow if this binding is
>> > acceptable.
>>
>> One minor comment below, otherwise:
>>
>> Acked-by: Rob Herring <robh@kernel.org>
>
> K, I'll send a series hopefully in a few weeks after some travel.
>
>> > +  If the phy's identifier is known then the list may contain an entry
>> > +  of the form: "ethernet-phy-idAAAA,BBBB" where
>>
>> I think this should be a period rather than a comma as we are not
>> separating a vendor ID from product ID.
>
> OK, that makes sense.
>
> Inspecting further, the format of the 32 bit AAAABBBB is actually
> broken out into:
>   OUI[3:18] || OUI[19:24] || MODEL[5:0] || REV[3:0]
>
> So a possible choice with the 'vendor ID,product ID' split is:
>   ethernet-phyOOOOO,MM.R
>
> xlate is:
>
> AAAABBBB = ((OOOOO >> 6) << 16) |
>            ((OOOOO & 0x3f) << 10) |
>            (MM << 4) |
>            R
>
> Which doesn't textually match the register value, or any other
> phy ID constants in the kernel, however makes more sense from the
> 'vendor ID,product ID' angle.
>
> Eg a Marvell 88E1310 would encode into the two options as:
>   ethernet-phy05043,29.0
>   ethernet-phy-id0141.0e90
>
> And the kernel has constants like this:
> include/linux/marvell_phy.h:#define MARVELL_PHY_ID_88E1318S 0x01410e90
>
> In light of this detail do you still like 'ethernet-phy-id0141.0e90' ?

I'm fine either way. Separating out the OUI had crossed my mind. That
probably does make the value in the DT more meaningful. Is the OUI
used anywhere in the kernel?

Rob