Re: [PATCH net-next v2 3/3] net: phy: marvell10g: add SFP+ support

[Andrew Lunn <andrew@lunn.ch>]

> The answer is... it depends.

Hi Russell

One issue we have had with phylink is people using the interfaces
wrongly. When asking this question, i was thinking about
documentation. Your answer suggests this method is not simply about
the validation you are doing here, it could also be about
configuration of the PHY to fit the module.

Maybe it would be good to add documentation somewhere about the range
of things this call can do?

> So, this patch reflects what can be done with the SFP+ slots on
> Macchiatobin boards today.

This all sounds very hardware dependent. So we are going to need some
more DT properties i guess. Have you thought about this?

Maybe we need to add compatibles sff,sfp+ and sff,sff+ ? Indicate the
board is capable of the higher speeds? And when sfp+/sff+ is used,
maybe a boolean to indicate it is also sff/sfp compatible?
sfp_select_interface() can then look at these properties and return
PHY_INTERFACE_MODE_NA if the board is not capable of supporting the
module?

Would it even make sense to make the PHY interface more like the MAC
interface? A validate function to indicate what it is capable of? A
configure function to configure its mode towards the SFP?

	  Andrew