On Mon, Apr 05, 2021 at 03:33:55PM +0200, Andrew Lunn wrote: > On Sun, Apr 04, 2021 at 09:23:55PM +0200, Danilo Krummrich wrote: > > So currently every driver should check for the flag MII_ADDR_C45 and report > > an > > error in case it's unsupported. > > > > What do you think about checking the bus' capabilities instead in > > mdiobus_c45_*()? This way the check if C45 is supported can even happen > > before > > calling the driver at all. I think that would be a little cleaner than > > having > > two places where information of the bus' capabilities are stored (return > > value > > of read/write functions and the capabilities field). > > > > I think there are not too many drivers setting their capabilities though, > > but > > it should be easy to derive this information from how and if they handle the > > MII_ADDR_C45 flag. > > I actually don't think anything needs to change. The Marvell PHY > probably probes due to its C22 IDs. The driver will then requests C45 > access which automagically get converted into C45 over C22 for your > hardware, but remain C45 access for bus drivers which support C45. > Thanks Andrew - I agree, for the Marvell PHY to work I likly don't need any change, since I also expect that it will probe with the C22 IDs. I'll try this soon.
However, this was about something else - Russell wrote: > > > We have established that MDIO drivers need to reject accesses for > > > reads/writes that they do not support [..] The MDIO drivers do this by checking the MII_ADDR_C45 flag if it's a C45 bus request. In case they don't support it they return -EOPNOTSUPP. So basically, the bus drivers read/write functions (should) encode the capability of doing C45 transfers. I just noted that this is redundant to the bus' capabilities field of struct mii_bus which also encodes the bus' capabilities of doing C22 and/or C45 transfers. Now, instead of encoding this information of the bus' capabilities at both places, I'd propose just checking the mii_bus->capabilities field in the mdiobus_c45_*() functions. IMHO this would be a little cleaner, than having two places where this information is stored. What do you think about that? > Andrew
