Re: [PATCH 1/2] of/phylib: Use device tree properties to initializeMarvell PHYs.

[David Daney]

On 11/18/2010 12:40 PM, Grant Likely wrote:
> On Wed, Nov 17, 2010 at 03:54:30PM -0800, David Daney wrote:
> > Some aspects of PHY initialization are board dependent, things like
> > indicator LED connections and some clocking modes cannot be determined
> > by probing.  The dev_flags element of struct phy_device can be used to
> > control these things if an appropriate value can be passed from the
> > Ethernet driver.  We run into problems however if the PHY connections
> > are specified by the device tree.  There is no way for the Ethernet
> > driver to know what flags it should pass.
> >
> > If we are using the device tree, the struct phy_device will be
> > populated with the device tree node corresponding to the PHY, and we
> > can extract extra configuration information from there.
> >
> > The next question is what should the format of that information be?
> > It is highly device specific, and the device tree representation
> > should not be tied to any arbitrary kernel defined constants.  A
> > straight forward representation is just to specify the exact bits that
> > should be set using the "marvell,reg-init" property:
> >
> >        phy5: ethernet-phy@5 {
> > 	reg =<5>;
> > 	device_type = "ethernet-phy";
>
> Some notes:
> - device_type is only relevant for real openfirmware platforms.  It
>    should not appear in dts files.

Documentation/powerpc/dts-bindings/phy.txt says device_type should be 
here.  I can remove it from my patch comment, but should it also be 
removed from the phy.txt file?

> - This example phy node needs a compatible property

Ok, what would you suggest?  Something like:

     compatible = "marvell,88e1145";

I can certainly do that, but I would note that the kernel probes these 
things and would completely ignore the compatible property.

> - This new binding needs to be documented.  You can use devicetree.org.

Agreed, I was planning to do that once the patch was approved.

Where would that go?  Vendor:Marvell, or Type:PHY/compatible=marvell,* 
... or somewhere else?

> > 	marvell,reg-init =
> > 		<0x00030010 0x5777>, /* Reg 3,16<- 0x5777 */
> > 		<0x00030011 0x00aa>, /* Reg 3,17<- 0x00aa */
> > 		<0x00030012 0x4105>, /* Reg 3,18<- 0x4105 */
> > 		<0x00030013 0x0060>; /* Reg 3,19<- 0x0060 */
> > 		<0x00020015 0x00300000>; /* clear bits 4..5 of Reg 2,21 */
> >        };


Thanks,
David Daney
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