From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A5D1C6FA8F for ; Wed, 30 Aug 2023 18:36:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231609AbjH3SgZ convert rfc822-to-8bit (ORCPT ); Wed, 30 Aug 2023 14:36:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343638AbjH3QaP (ORCPT ); Wed, 30 Aug 2023 12:30:15 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E04DC107 for ; Wed, 30 Aug 2023 09:30:11 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4RbV5F42vLz6K5WY; Thu, 31 Aug 2023 00:25:21 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Wed, 30 Aug 2023 17:30:09 +0100 Date: Wed, 30 Aug 2023 17:30:08 +0100 From: Jonathan Cameron To: Nuno Sa CC: , Jonathan Cameron , Olivier Moysan Subject: Re: [RFC PATCH 0/3] Add converter framework Message-ID: <20230830173008.000024a3@Huawei.com> In-Reply-To: <20230830172903.0000027f@Huawei.com> References: <20230804145342.1600136-1-nuno.sa@analog.com> <20230830172903.0000027f@Huawei.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml100005.china.huawei.com (7.191.160.25) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Wed, 30 Aug 2023 17:29:03 +0100 Jonathan Cameron wrote: > On Fri, 4 Aug 2023 16:53:38 +0200 > Nuno Sa 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@foss.st.com/ > > 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@gmail.com/ > > > > 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 > > >