On Tue, Aug 25, 2020 at 12:16:56PM -0500, Pierre-Louis Bossart wrote:
One possible objection is that this code could have been handled with regmap-sdw.c. However this is a new spec addition not handled by every SoundWire 1.1 and non-SDCA device, so there's no reason to load code that will never be used.
Also in practice it's extremely unlikely that CONFIG_REGMAP would not be selected with CONFIG_REGMAP_MBQ selected. However there's no functional dependency between the two modules so they can be selected separately.
The other thing I'm wondering here is about compatibility - is this something we can enumerate at runtime and if so couldn't this be done more like how we handle the various I2C and SMBus variants so the driver just says it wants a SoundWire regmap and then based on the capabilities of the device and the controller the regmap decides if it can use MBQ or not on the current system?