Re: [PATCH v2 02/15] net: phy: adin: hook genphy_read_abilities() to get_features

[Andrew Lunn]

On Thu, Aug 08, 2019 at 03:30:13PM +0300, Alexandru Ardelean wrote:
> The ADIN PHYs can operate with Clause 45, however they are not typical for
> how phylib considers Clause 45 PHYs.
> 
> If the `features` field & the `get_features` hook are unspecified, and the
> device wants to operate via Clause 45, it would also try to read features
> via the `genphy_c45_pma_read_abilities()`, which will try to read PMA regs
> that are unsupported.
> 
> Hooking the `genphy_read_abilities()` function to the `get_features` hook
> will ensure that this does not happen and the PHY features are read
> correctly regardless of Clause 22 or Clause 45 operation.

I think we need to stop and think about a PHY which supports both C22
and C45.

How does bus enumeration work? Is it discovered twice?  I've always
considered phydev->is_c45 means everything is c45, not that some
registers can be accessed via c45. But the driver is mixing c22 and
c45. Does the driver actually require c45? Are some features which are
only accessibly via C45? What does C45 actually bring us for this
device?

     Andrew