Am 29.08.2014 16:08, schrieb Michal Simek: > On 08/25/2014 10:21 PM, Florian Fainelli wrote: >> On 08/25/2014 10:46 AM, Jason Gunthorpe wrote: >>> On Fri, Aug 22, 2014 at 01:47:09PM -0700, Florian Fainelli wrote: >>> >>>>> - the ID based strings seem to be not needed since, IIUC, the core >>>>> reads the ID from the PHY and uses it, so I just left it out not >>>>> trying to figure out how to obtain the correct ID >>>> >>>> It is not needed, but it is one way to specify a PHY device if you do >>>> not know what compatible string to use instead. >>> >>> No, it is a way to specify a PHY device if the kernel can't auto probe >>> the Phy ID. >>> >>> Last I checked, the kernel doesn't support plain text compatible >>> strings for phys - everything is driven on the phy id, either auto >>> probed or specified in the DT. >> >> That's right. Some PHY drivers might be relying on specific compatible >> strings though, but not the core PHY library that probes and maps a >> driver to a PHY node. >> >>> >>>>> - the marvell compatible strings are used in our vendor tree. They >>>>> aren't used anywhere but in our vendor tree. I though keeping them is >>>>> nice since it identifies the PHY fully. And in case that level of >>>>> detail is needed at some point it is already there. >>>> >>>> And this is the recommended way to do it in case we ever need to key a >>>> software decision based on the hardware. >>> >>> All compatible strings need to be documented. >>> >>> .. and they need to encode more information than you get from the phy >>> id - die revsision, package option, functional options, voltage >>> codes. Etc. >>> >>> .. and they actually need to be *right* >> >> Agreed. >> >>> >>> An example: The kernel reports 88E1318S for all four chips in that >>> family, AFAIK you have to read the package marking to figure out which >>> you have (it is the same die, with options switched on/off at >>> packaging time). People have already posted patches trying to >>> helpfully add a 'marvell,88E1318S' compatible string based on kernel >>> output. Except it is wrong, it isn't actually the '8S version in the >>> HW. >>> >>> Even worse, Marvell has a whole series of socket compatible phys. Just >>> because the board the DT author looked at has a '318, doesn't mean >>> that every board ever made will. We've actually already been switching >>> between the 318 and 318S for production depending on which has part >>> availability. >>> >>> Basically: don't try to override self-discoverable hardware in DT >>> without a really good reason. >> >> I think that's a very good point, at the very least let's use a >> compatible string that contains the full 32-bits PHY OUI. > > I think resolution is: > 1. Do not use marvell,88e1518 because it is not listed anywhere > 2. Do not add ethernet-phy-idAAAA.BBBB because it breaks autodetection > if there is different phy on the board and we shouldn't restrict us in this. > In spite of autodetection takes some time. > 3. "ethernet-phy-ieee802.3-c22" is optional that's why doesn't need to be added > 4. Any listed compatible string has to be parsed which takes time > > That's why I think make sense not to use any compatible string. > This should give us all flexibility which we want to have. Sorry, but we do need some node that we can reference via phy-handle from the gem node, don't we? In that case, is not specifying any compatible string a valid option? If you don't want to specify the IDs, then I would've assumed we need to specify the -c22 in order to have *some* compatible string in order to trigger loading of the appropriate driver module. Regards, Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
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