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 375B7C433EF for ; Thu, 9 Jun 2022 15:16:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344274AbiFIPQj (ORCPT ); Thu, 9 Jun 2022 11:16:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344363AbiFIPQ3 (ORCPT ); Thu, 9 Jun 2022 11:16:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF44B49902; Thu, 9 Jun 2022 08:16:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6C93961EE0; Thu, 9 Jun 2022 15:16:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 249F5C34114; Thu, 9 Jun 2022 15:16:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654787784; bh=g7Oqc6okGrgAx2RptXrZI6uH5NS5zvIuypnAIqUna2w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=o7w8oySaar1T/ReMIGIxfKrU0DzfO2Vm6KkavvWw68VYTbKQ1ZTYGtcFEqJy1u5o/ GTndLqfts78bw5+P8JvEV8SJqki4yEd7oTtqg5X3HZ0EhaifDeGI4Ee1nIkNHKxy3b 8GfMr58B7Jv3PM+T6NHEUILQDVLXZq8s8YyT5ZY1nrLtoWkeng381ucXf0Rfwoe0MQ blAWV9JWKwfBpKZDEBOJ/Eg8ZkATZOfs8BaYklyL+cD09UvC9HBE9MuLsiLXW+QpIv JcQp5yWwOBzvU6CWafl5Vm3g8O4Z8aQXFzISLQThLRjtRxx+sFJ5mTTB4PYk+0IRe4 5OltI75EVahNA== Date: Thu, 9 Jun 2022 16:16:18 +0100 From: Mark Brown To: Martin =?utf-8?Q?Povi=C5=A1er?= Cc: Liam Girdwood , Rob Herring , Krzysztof Kozlowski , Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Mark Kettenis , Hector Martin , Sven Peter , asahi@lists.linux.dev Subject: Re: [RFC PATCH v2 5/5] ASoC: apple: Add macaudio machine driver Message-ID: References: <20220606191910.16580-1-povik+lin@cutebit.org> <20220606191910.16580-6-povik+lin@cutebit.org> <8961DDD2-93FF-4A18-BCA2-90FCE298F517@cutebit.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="9pewpbWOkjDXgIrF" Content-Disposition: inline In-Reply-To: <8961DDD2-93FF-4A18-BCA2-90FCE298F517@cutebit.org> X-Cookie: Space is limited. Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --9pewpbWOkjDXgIrF Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 09, 2022 at 04:09:57PM +0200, Martin Povi=C5=A1er wrote: > > On 9. 6. 2022, at 15:33, Mark Brown wrote: > >> + /* > >> + * Primary FE > >> + * > >> + * The mclk/fs ratio at 64 for the primary frontend is important > >> + * to ensure that the headphones codec's idea of left and right > >> + * in a stereo stream over I2S fits in nicely with everyone else's. > >> + * (This is until the headphones codec's driver supports > >> + * set_tdm_slot.) > >> + * > >> + * The low mclk/fs ratio precludes transmitting more than two > >> + * channels over I2S, but that's okay since there is the secondary > >> + * FE for speaker arrays anyway. > >> + */ > >> + .mclk_fs =3D 64, > >> + }, > > This seems weird - it looks like it's confusing MCLK and the bit clock > > for the audio bus. These are two different clocks. Note that it's very > > common for devices to require a higher MCLK/fs ratio to deliver the best > > audio performance, 256fs is standard. > On these machines we are not producing any other clock for the codecs > besides the bit clock, so I am using MCLK interchangeably for it. (It is > what the sample rate is derived from after all.) Please don't do this, you're just making everything needlessly hard to understand by using standard terminology inappropriately and there's a risk of breakage further down the line with drivers implementing the standard ops. > One of the codec drivers this is to be used with (cs42l42) expects to be > given the I2S bit clock with > snd_soc_dai_set_sysclk(dai, 0, mclk, SND_SOC_CLOCK_IN); That's very, very non-standard... > I can rename mclk to bclk in all of the code to make it clearer maybe. > Also the platform driver can take the bit clock value from set_bclk_ratio, > instead of set_sysclk from where it takes it now. The cs42l42 driver I can > patch too to accept set_bclk_ratio. =2E..indeed, set_bclk_ratio() is a better interface for setting the bclk ratio - the CODEC driver should really be doing that as well. > > This shouldn't be open coded in a driver, please factor it out into the > > core so we've got an API for "set limit X on control Y" then call that. > There=E2=80=99s already snd_soc_limit_volume, but it takes a fixed contro= l name. > Can I extend it to understand patterns beginning with a wildcard, like > '* Amp Gain Volume=E2=80=99? 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