Re: [PATCH net 2/2] DT: phy.txt: Clarify expected compatible values

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Jan 27, 2016 at 08:41:56AM -0800, Olof Johansson wrote:
> On Tue, Jan 26, 2016 at 4:11 PM, Andrew Lunn <andrew@lunn.ch> wrote:
> > PHY devices may only list clause 22, 45, and their PHY identifier
> > values as compatible values. No other compatible strings are allowed.
> > Make this clear in the documentation, and remove examples where
> > make/model compatible strings are listed.
> >
> > Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> 
> I'm not sure I agree with the disallowing here. It's common practice
> to use a specific compatible to describe the actual hardware used, in
> case it's needed in the future for some driver to distinguish
> behavior, etc.
> 
> So while it should be required to include the clause compats, having a
> more specific one in there should be acceptable.

Hi Olof

Matching PHY devices to drivers has never used to compatible string,
other than the "ethernet-phy-XXXX.YYYY" string.  The PHY has two
registers containing a manufacture id, device id and revision,
registers 2 and 3. These are the XXXX and YYYY. The core code reads
these values, or uses the values from the ethernet-phy-XXXX.YYYY, and
uses them to find a driver which supports these values.

A make/model string is less specific than ethernet-phy-XXXX.YYYY.

I will reword the changelog to make it clear that
"ethernet-phy-XXXX.YYYY" is allowed.

Thanks
	Andrew