On Tue, Jun 27, 2017 at 4:05 PM, Corentin Labbe <clabbe.montjoie@xxxxxxxxx> wrote: > On Mon, Jun 26, 2017 at 01:18:23AM +0100, André Przywara wrote: >> On 31/05/17 08:18, Corentin Labbe wrote: >> > The dwmac-sun8i is a heavy hacked version of stmmac hardware by >> > allwinner. >> > In fact the only common part is the descriptor management and the first >> > register function. >> >> Hi, >> >> I know I am a bit late with this, but while adapting the U-Boot driver >> to the new binding I was wondering about the internal PHY detection: >> >> >> So here you seem to deduce the usage of the internal PHY by the PHY >> interface specified in the DT (MII = internal, RGMII = external). >> I think I raised this question before, but isn't it perfectly legal for >> a board to use MII with an external PHY even on those SoCs that feature >> an internal PHY? >> On the first glance that does not make too much sense, but apart from >> not being the correct binding to describe all of the SoCs features I see >> two scenarios: >> 1) A board vendor might choose to not use the internal PHY because it >> has bugs, lacks features (configurability) or has other issues. For >> instance I have heard reports that the internal PHY makes the SoC go >> rather hot, possibly limiting the CPU frequency. By using an external >> MII PHY (which are still cheaper than RGMII PHYs) this can be avoided. >> 2) A PHY does not necessarily need to be directly connected to >> magnetics. Indeed quite some boards use (RG)MII to connect to a switch >> IC or some other network circuitry, for instance fibre connectors. >> >> So I was wondering if we would need an explicit: >> allwinner,use-internal-phy; >> boolean DT property to signal the usage of the internal PHY? >> Alternatively we could go with the negative version: >> allwinner,disable-internal-phy; >> >> Or what about introducing a new "allwinner,internal-mii-phy" compatible >> string for the *PHY* node and use that? >> >> I just want to avoid that we introduce a binding that causes us >> headaches later. I think we can still fix this with a followup patch >> before the driver and its binding hit a release kernel. >> >> Cheers, >> Andre. >> > > I just see some patch, where "phy-mode = internal" is valid. > I will try to find a way to use it Can you provide a link? I'm not a fan of using phy-mode for this. There's no guarantee what mode the internal PHY uses. That's what phy-mode is for. In any case, we should fix this before 4.13 is released. ChenYu -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
