Subject: Re: [PATCH devicetree v3] dt-bindings: phy: Add `tx-p2p-microvolt` property binding

From: Marek Behún <[email-masked]>
Date: Sun, 6 Feb 2022 18:54:13 +0100

On Fri, 4 Feb 2022 20:18:40 -0600
Rob Herring <[email-masked]> wrote:

> On Fri, Jan 21, 2022 at 11:18:09AM -0800, Florian Fainelli wrote:
> > On 1/19/22 5:11 AM, Marek Behún wrote:  
> > > Common PHYs and network PCSes often have the possibility to specify
> > > peak-to-peak voltage on the differential pair - the default voltage
> > > sometimes needs to be changed for a particular board.
> > > 
> > > Add properties `tx-p2p-microvolt` and `tx-p2p-microvolt-names` for this
> > > purpose. The second property is needed to specify the mode for the
> > > corresponding voltage in the `tx-p2p-microvolt` property, if the voltage
> > > is to be used only for speficic mode. More voltage-mode pairs can be
> > > specified.
> > > 
> > > Example usage with only one voltage (it will be used for all supported
> > > PHY modes, the `tx-p2p-microvolt-names` property is not needed in this
> > > case):
> > > 
> > >   tx-p2p-microvolt = <915000>;
> > > 
> > > Example usage with voltages for multiple modes:
> > > 
> > >   tx-p2p-microvolt = <915000>, <1100000>, <1200000>;
> > >   tx-p2p-microvolt-names = "2500base-x", "usb", "pcie";
> > > 
> > > Add these properties into a separate file phy/transmit-amplitude.yaml,
> > > which should be referenced by any binding that uses it.  
> > 
> > p2p commonly means peer to peer which incidentally could be confusing,
> > can you spell out the property entire:
> > 
> > tx-peaktopeak-microvolt or:
> > 
> > tx-pk2pk-microvolt for a more compact name maybe?  
> 
> Peer to peer makes little sense in terms of a voltage. I think this is 
> fine as-is.

Cool. Should this get merged via devicetree, or via phy maintainers?
Or should I resend this together with patches that make use of this
property? (In that case can you add your Ack?)

Thanks.

Marek