On October 14, 2016 7:25:14 PM CEST, Andrew Lunn <and...@lunn.ch> wrote:
>> So after calling BMCR_PDOWN, the PHYSID1 and PHYSID2 registers are
>> no longer readable. Is that expected?
>You are making two changes here. Is it the SGMII power down which is
>causing the id registers to return 0xffff, or the BMCR_PDOWN.
I would be curious to know about that as well.
>The generic suspend code sets the PDOWN bit, so it is assuming the PHY
>will respond afterwards.
After reading the spec again, it does not appear to me that a PHY with PDOWN
set is guaranteed or even required to respond to other register reads such as
MII_PHYID1/2, in which case we may have to implement a MDIO bus reset routine
which clears PDOWN for all PHYs that we detect(ed), or as Andrew suggested,
utilize the matching by compatible string with the PHY OUI in it.