On Wed, 30 Aug 2023 17:29:03 +0100 Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> wrote: > On Fri, 4 Aug 2023 16:53:38 +0200 > Nuno Sa <nuno.sa@xxxxxxxxxx> wrote: > > > This is the initial RFC following the discussion in [1]. I'm aware this is > > by no means ready for inclusion and it's not even compilable since in > > the RFC I did not included the patch to add component_compare_fwnode() > > and component_release_fwnode(). > > Whilst I haven't read this through yet, I suspect Olivier will be able to > offer some insight on some of this and likewise you may be able to > point out pitfalls etc in his series (I see you did some review already :) > > https://lore.kernel.org/linux-iio/20230727150324.1157933-1-olivier.moysan@xxxxxxxxxxx/ > > Both are about multiple interacting components of an overall datapath. > Whether there is commonality isn't yet clear to me. Works better if I actually remember to CC Olivier. +CC Olivier! > > > > > The goal is to have a first feel on the > > direction of the framework so that if I need to drastically change it, > > better do it now. The RFC also brings the ad9647 and the axi_adc core to > > the same functionality we have now upstream with one extra fundamental > > feature that is calibrating the digital interface. This would be very > > difficult to do with the current design. Note that I don't expect any > > review on those drivers (rather than things related to the framework). > > > > I also want to bring up a couple of things that I've > > been thinking that I'm yet not sure about (so some feedback might make > > mind in one direction or another). > > > > 1) Im yet not sure if I should have different compatibles in the > > axi-adc-core driver. Note this soft core is a generic core and for every > > design (where the frontend device changes or has subtle changes like > > different number of data paths) there are subtle changes. So, the number > > of channels might be different, the available test patterns might be > > different, some ops might be available for some designs but not for > > others, etc... > > I don't suppose there is any chance Analog can make at least some of this > discoverable from the hardware? Capability registers etc in the long > run. Can't fix what is already out there. > > > With a different compatible we could fine tune > > those differences (with a chip_info like structure) and pass some const > > converter_config to the framework that would allow it to do more safety > > checks and potentially reduce the number of converter_ops. > > OTOH, starting to add all of these compatibles might become messy in the > > long run and will likely mean that we'll always have to change both > > drivers in order to support a new frontend. And the frontend devices > > should really be the ones having all the "knowledge" to configure the > > soft core even if it means more converter_ops (though devicetree might > > help as some features are really HW dependent). I more inclined to just > > leave things as-is in the RFC. > > I'm fine with putting this stuff in DT where possible. > > > > > 2) There are some IIO attributes (like scale, frequency, etc) that might > > be implemented in the soft cores. I still didn't made my mind if I should just > > have a catch all read_raw() and write_raw() converter_ops or more fine > > tuned ops. Having the catch all reduces the number of ops but also makes > > it more easier to add stuff that ends up being not used anymore and then > > forgotten. There are also cases (eg: setting sampling frequency) where > > we might need to apply settings in both the frontend and the backend > > devices which means having the catch all write_raw() would be more > > awkward in these case. I'm a bit more inclined to the more specific ops. > > It's the kernel - we can always change the internal API later as long as we > don't touch the user space part. Go with your gut feeling today and > if it changes this sort of refactor usually isn't that bad. > > > > > 3) I also placed this in addac as this is mostly used in high speed DACs > > and ADCs but maybe we should just have it in the top level directory > > just in case this is started to be used in different type of devices? > > Easy to change later so right now I don't care where it is. > > > > > 4) Some function and data names are also starting to become very big so > > if there are no objections I will move all to use conv instead of full > > converter. Or maybe something a bit more generic (converter is a bit specific > > I know)? > > Abrv. fine as long as consistenty used. > > > > > I would love to hear some ideas about the above... > > > > Anyways, I should also mention that the only visible ABI breakage is in > > the IIO device name. Before it was named "adi-axi-adc" and now it's > > "ad9647" which is what makes sense actually. With the current approach > > we would not be able to actually distinguish between designs. > > Given that will probably only result in support calls to ADI I'm fine with > that breakage. :) > > > > > So my plan for the actual series will be to just add the framework and migrate > > the current drivers to it with the same functionality as they have now (not > > sure if it will be viable to migrate the drivers in a way each commit is > > functional - unless we convert both drivers in one commit). > Make sure they build. It's fine to end up with some non functional stubs > during such a migration. > > > After that > > point, I will start adding all the missing features (and devices) to the > > ad9467 driver. To note that I also plan to include the axi-dac driver in > > the first series and that will require IIO DMA output buffer support > > so we might need to cherry-pick those patches from Paul's DMABUF series. > As mentioned in reply to that, I'm fine with you carrying Paul's miniseries > in your patch set to make this all easy to manage. > > Jonathan > > > > > Thanks! > > - Nuno Sá > > > > [1]: https://lore.kernel.org/linux-iio/dac3967805d7ddbd4653ead6d50e614844e0b70b.camel@xxxxxxxxx/ > > > > Nuno Sa (3): > > iio: addac: add new converter framework > > iio: adc: ad9647: add based on converter framework > > iio: adc: adi-axi-adc: add based on new converter framework > > > > drivers/iio/adc/ad9467_new.c | 830 ++++++++++++++++++++++++++++ > > drivers/iio/adc/adi-axi-adc-new.c | 405 ++++++++++++++ > > drivers/iio/addac/converter.c | 547 ++++++++++++++++++ > > include/linux/iio/addac/converter.h | 485 ++++++++++++++++ > > 4 files changed, 2267 insertions(+) > > create mode 100644 drivers/iio/adc/ad9467_new.c > > create mode 100644 drivers/iio/adc/adi-axi-adc-new.c > > create mode 100644 drivers/iio/addac/converter.c > > create mode 100644 include/linux/iio/addac/converter.h > > >
