Hi Lars and Jean, Are you taking this patch further to take care about ACPI related stuff submitted by Mika? Thanks, Srinivas On Fri, 2014-10-03 at 12:46 +0200, Wolfram Sang wrote: > > > Ok, looks like there are two main differences in the two implementations. > > > > > > 1) The ACPI one uses a integer index and the DT one uses a string index to > > > lookup the device. > > > > > > The problem with the index lookup is that the order is binding specific. So > > > it might be different between e.g. the devicetree binding and the ACPI > > > binding. This makes it quite hard to use the API in a generic way and you'd > > > end up with hacks like: > > > > > > if (client->dev.of_node) > > > index = 3; > > > else if (ACPI_COMPANION(client->dev)) > > > index = 1; > > > else > > > index = 5; > > > > > > > Indeed. > > > > > So we might need a extra translation table which maps a name to a ACPI index > > > and then we could use the name as the generic index in the driver. > > > > Good thing is that ACPI 5.1 _DSD finally allows us to use similar naming > > as the DT has been doing. Problem is that we need to support both the > > new way *and* the older index lookup somehow :-/ > > > > > 2) The ACPI implementation returns the i2c_board_info and the adapter, while > > > the DT implementation returns the instantiated I2C client device. > > > > > > It might make sense to have both. I image that most drivers are just > > > interested in creating a new client device and will simply pass the board > > > info and adapter they got to i2c_new_device(). In this case it makes sense > > > to have a helper function which already does this internally to avoid > > > boilerplate code duplication. > > > > I agree. How about making that helper a wrapper around the function that > > returns both i2c_board_info and an adapter? > > > > > There will probably some special cases though in which case the driver wants > > > to get the adapter and the board info and then manually call > > > i2c_new_device() after having done some additional steps. > > > > Yes, if the alternative address happens to be on another bus. That > > should at least be possible with this API. > > Thanks for the discussion so far! I'll wait and see if some patches come > out of it and mark this one as deferred for now. > -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
