Hi Boris, > This patch series is a proposal for a new I3C [1] subsystem. Nice. Good luck with that! Some hi-level comments from me related to I2C. I can't say a lot more because the specs are not public :( > - the bus element is a separate object and is not implicitly described > by the master (as done in I2C). The reason is that I want to be able > to handle multiple master connected to the same bus and visible to > Linux. > In this situation, we should only have one instance of the device and > not one per master, and sharing the bus object would be part of the > solution to gracefully handle this case. > I'm not sure if we will ever need to deal with multiple masters > controlling the same bus and exposed under Linux, but separating the > bus and master concept is pretty easy, hence the decision to do it > now, just in case we need it some day. From my experience, it is a good thing to have this separation. > - I2C backward compatibility has been designed to be transparent to I2C > drivers and the I2C subsystem. The I3C master just registers an I2C > adapter which creates a new I2C bus. I'd say that, from a > representation PoV it's not ideal because what should appear as a > single I3C bus exposing I3C and I2C devices here appears as 2 > different busses connected to each other through the parenting (the > I3C master is the parent of the I2C and I3C busses). > On the other hand, I don't see a better solution if we want something > that is not invasive. I agree this is the least invasive and also the most compatible approach. The other solution would probably be to have some kind of emulation layer? > I'd also like to get feedback on the doc. Should I detail a bit more > the protocol or the framework API? Is this the kind of things you > expect in a subsystem doc? Since the spec is not public, details about the protocol will be especially useful, I'd say. Regards, Wolfram
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