Em Tue, 24 Mar 2020 12:01:22 +0100 Wolfram Sang <wsa@xxxxxxxxxxxxx> escreveu: > On Tue, Mar 24, 2020 at 10:49:55AM +0000, Kieran Bingham wrote: > > +cc: linux-i2c@xxxxxxxxxxxxxxx > > Moving /this/ to the linux-i2c list ;-) > > > > Thanks Wolfram, > > > > On 24/03/2020 10:27, Wolfram Sang wrote: > > > > > >> Maybe we should have a whole virtual I2C bus for virtual devices :-) > > >> > > >> (Hrm, that started out as a joke, and now I'm not sure if it's a real > > >> option or not...) > > > > > > Just one final thought: I think this is actually the best option. Zero > > > chance of address collisions (which could happen if you have a not > > > perfectly-described real HW bus). No RPM mangling of real and virtual > > > devices. A clear seperation what is real and what is virtual. Plus, you > > > can implement it right away, no need to wait for the dynamic address > > > assignment. > > > > Agreed - even better all round! But I presume we don't yet have a > > 'virtual' i2c bus? So it's a patch-set to do first? Or is it already > > feasible? > > From what I understand, you won't need an API for that. What I > understand: > > There will be a master device (a DVB or something). This will register > its own i2c_adapter with a dummy .xfer callback. The sub-devices will be > i2c_clients, then. Yes. That's what the current drivers that have integrated hardware at the same silicon (like rtl28xx) do: their .xfer callback splits the I2C addresses reserved for "internal" devices, and use a different set of registers to handle those, instead of the normal ones used to communicate with a real I2C hardware. The cx231xx uses a different strategy: it has multiple I2C buses, being one of them reserved for its own integrated I2C like bus. > I don't know how you want communication between > those. Maybe the .xfer callback will need to do some message parsing? > Thanks, Mauro
