On Tue, Jan 26, 2016 at 06:09:00PM -0800, Andrey Smirnov wrote: > On Tue, Jan 26, 2016 at 1:55 PM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > > On Mon, Jan 25, 2016 at 09:55:58PM -0800, Andrey Smirnov wrote: > >> Add commands for low-level access to MDIO bus. > > > > Do we really need this? We can already read/write phy registers using > > /dev/phyx which imo is quite convenient since it can be accessed with > > regular md/mw commands. > > > > This of course is currently limited to the phys that are actually > > registered, you can't just bang on MDIO addresses on which no phys are > > registered. Maybe we could register all phys on a MDIO bus instead of > > only the used ones? > > Just to explain the purpose of this patch -- there are number of > reasons we might want to be able to access "unregistered" PHYs: > > - Not all MDIO attached devices would have PHYSID1,2 registers > available which might cause mdiobus_scan() to not detect those PHYs > > - MDIO bus troubleshooting > > As for registering all PHYs on a bus, correct me if I am wrong but > that would result in 32*N number of entries in /dev, where N is number > of MDIO buses in the system. The device I am working with right now > has 3 MDIO buses which would mean that I'd end up with 96 additional > entries in /dev, which might be a little bit overwhelming from UI > point of view. The other UI problem with that approach is that > /dev/phy's are numbered linearly so in order to figure out how to > access device on bus N at address M, user would have to perform N*32 + > M in their head. We could register the phys with name like: "mdio%d-phy%02x", dev->bus->dev.id, mdev->addr That would make it clear which phy belongs to which bus. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
