[Now with the proper email to Luca, sorry about that...] 2022-05-16 at 09:57, Peter Rosin wrote: > 2022-05-14 at 16:26, Wolfram Sang wrote: >> On Tue, Apr 12, 2022 at 10:50:45AM +0200, Vincent Whitchurch wrote: >>> When drivers with ->detect callbacks are loaded, the I2C core does a >>> bunch of transactions to try to probe for these devices, regardless of >>> whether they are specified in the devicetree or not. (This only happens >>> on I2C controllers whose drivers enable the I2C_CLASS* flags, but this >>> is the case for generic drivers like i2c-gpio.) >>> >>> These kinds of transactions are unnecessary on systems where the >>> devicetree specifies all the devices on the I2C bus, so add a property >>> to indicate that the devicetree description of the hardware is complete >>> and thus allow this discovery to be disabled. >> Hmm, I don't think the name is fitting. "no-detect" is the desired >> behaviour but a proper description is more like "bus-complete" or >> something? >> >> That aside, I am not sure we should handle this at DT level. Maybe we >> should better change the GPIO driver to not populate a class if we have >> a firmware node? > We also have the somewhat related address translation case (which I > still need to look at). [Adding Luca to Cc] > > https://lore.kernel.org/lkml/20220206115939.3091265-1-luca@xxxxxxxxxxxxxxxx/ > > If a bus is "bus-complete", then address translation could use > any unused address instead of from an explicit list of addresses. > I.e. the "i2c-alias-pool" in the binding in patch 4/6 of that > series could be made optional if the bus is "bus-complete". > > Not sure how much value there is in that? > > Cheers, > Peter
