On 12/19/23 17:53, Mark Brown wrote: > On Tue, Dec 19, 2023 at 05:50:30PM +0100, Pierre-Louis Bossart wrote: > >>> grep for regmap_.*async - cs_dsp.c is the upstream example in a driver, >>> or there's the rbtree cache sync code which uses a back door to go into >>> an async mode. Basically just variants of all the normal regmap I/O >>> calls with a _complete() call you can use to wait for everything to >>> happen. The implementation is a bit heavyweight since it was written to >>> work with fairly slow buses. > >> I spent a fair amount of time this afternoon trying to understand the >> regmap_async parts, and I am not following where in the code there is an >> ordering requirement/enforcement between async and sync usages. > > The only actual async implementation is SPI which processes things in > order of submission, the sync API wraps the async API. > >> Also is this just me spacing out or there is no regmap_raw_read_async()? > > Right, there was never any need. ok. I am starting to think that we could have a new type of regmap, say "regmap-sdw-bra", where the use of write_raw_async() would rely on the send/wait bus primitives, and write_raw() would fallback to the regular read/write commands. We'd need a mutual exclusion to prevent parallel async/sync access to the same regmap. In other words, "memory" areas that are used for firmware downloads would be moved to a different regmap with async capabilities and no caching support.
