On Wed, 18 Jan 2017 16:20:10 -0600 Rob Herring <robh@xxxxxxxxxx> wrote: > On Tue, Jan 17, 2017 at 02:36:50PM +1100, Thomas Petazzoni wrote: > > Hello, > > > > (Side note: you guys should learn about stripping irrelevant parts of > > an e-mail when replying!) > > > > On Mon, 16 Jan 2017 09:40:32 +0100, Boris Brezillon wrote: > > > > > > Well this is OK I guess, but then you can also use "mediatek,mt8173-nor" > > > > as the oldest supported compatible and be done with it, no ? It looks a > > > > bit crappy though, I admit that ... > > > > > > Let's stop bikeshedding and wait for DT maintainers feedback > > > before taking a decision ;-). > > > > > > Rob, Mark, any opinion? > > > > Sigh, is how to do compatibles really not yet understood? Apparently not, and I fear this is not the last misunderstanding on my side ;-). > > > I agree that a clarification would be good. There are really two > > options: > > > > 1. Have two compatible strings in the DT, the one that matches the > > exact SoC where the IP is found (first compatible string) and the > > one that matches some other SoC where the same IP is found (second > > compatible string). Originally, Linux only supports the second > > compatible string in its device driver, but if it happens that a > > difference is found between two IPs that we thought were the same, > > we can add support for the first compatible string in the driver, > > with a slightly different behavior. > > This. And no wildcards in the compatible string. > > > 2. Have a single compatible string in the DT, matching the exact SoC > > where the IP is found. This involves adding immediately this > > compatible string in the corresponding driver. > > I wouldn't object to this from a DT perspective as I have no clue > generally if IP blocks are "the same" or not. Subsystem maintainers will > object though. > > > I've not really been able to figure out which of the two options is the > > most future-proof/appropriate. > > They are both future-proof. #2 has the disadvantage of requiring a > kernel update for a new SoC. > > Rob -- 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
