Messages in this thread | | | Date | Sun, 8 Aug 2004 23:54:58 +0200 | From | Roger Luethi <> | Subject | Re: [2/3] via-rhine: de-isolate PHY |
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On Sun, 08 Aug 2004 23:04:06 +0200, Manfred Spraul wrote: > Roger Luethi wrote: > >>I know that PHYs go into isolate mode if the startup id is wired to 0, > > > >Wouldn't that be s/go/can go/ ? > > > I don't have the MII standard, my knowledge is from the DP83840A specs: > The pin description contains a section about the phy ids: > During power up five pins are latched to determine the initial phy address. > Then the following sentence in bold: "An address selection of all zeros > (00000) will result in a PHY isolation condition".
I suppose all PHYs do that. Even if they don't, though, I should be safe as long as I de-isolate unconditionally (instead of testing for phy_id==0).
> I've reread the DP specs and I now think that your current patch is > sufficient: > The isolate state is independant from the phy address - a non-zero phy > can be in isolate mode and the phy zero can be non-isolated. The phy id
Stands to reason. A PHY that can't get out of isolation wouldn't be very useful.
> If this is really true then handling phy 0 is trivial: > First scan 1-31. If nothing found: try 0. If a phy is found: clear the > isolate bit and then use phy 0.
Makes sense. The Rhine is actually pretty neat in that regard, I've been able to drop the PHY scanning entirely.
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