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 X-Spam-Level: X-Spam-Status: No, score=-7.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 012A9C433F5 for ; Thu, 16 Sep 2021 12:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D636160EE0 for ; Thu, 16 Sep 2021 12:26:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239504AbhIPM15 (ORCPT ); Thu, 16 Sep 2021 08:27:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:37124 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239363AbhIPM1v (ORCPT ); Thu, 16 Sep 2021 08:27:51 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 26EA360F25; Thu, 16 Sep 2021 12:26:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631795190; bh=mfX29/di/xilhJPTUe/47Dt9l+sLXh8n1/Bzm8nigXo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dot7UTFG9z5RDoKt9YwghU4gkD4y/1MEbPdmOHoSGOeFeQji17JwBeN4q3v3btsll KjYI9NO8L81+jJYoA3/jm81mU0MgfS6GoThC/wrSXbfjXVWKnyEt3ACq6ylbFiw+Oa 2dd/mbMaYaFyYpP0cwWTNRGJcZnoZY+YOrDEybg5aEKgEflxSVHSycN1NW3s98A17/ QEb7g5+IoM+MrG/lX8TzMEELRy7gCn6wvNQMN6MComagWtYo/VixmF8TN+o00lA0I5 dG9SGeD13axlKcBfB7jyvb68L8mgCHFwQLw2oqTuBOB+6rZnOUbJdwNj1qistYfVzG 0gwbWdMYlARow== Date: Thu, 16 Sep 2021 13:25:49 +0100 From: Mark Brown To: Nicolas Frattaroli Cc: Liam Girdwood , Rob Herring , Heiko Stuebner , linux-rockchip@lists.infradead.org, alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 2/4] dt-bindings: sound: add rockchip i2s-tdm binding Message-ID: <20210916122549.GF5048@sirena.org.uk> References: <20210903231536.225540-1-frattaroli.nicolas@gmail.com> <20210903231536.225540-3-frattaroli.nicolas@gmail.com> <20210915141012.GC12513@sirena.org.uk> <42974939.Tn3hggVSkZ@archbook> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="hUH5gZbnpyIv7Mn4" Content-Disposition: inline In-Reply-To: <42974939.Tn3hggVSkZ@archbook> X-Cookie: We've upped our standards, so up yours! User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --hUH5gZbnpyIv7Mn4 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Sep 15, 2021 at 07:06:14PM +0200, Nicolas Frattaroli wrote: > On Mittwoch, 15. September 2021 16:10:12 CEST Mark Brown wrote: > > Why is this not part of the normal bus format configuration? I don't > > know what this is but it sounds a lot like I2S mode... > This affects all TDM I2S modes, i.e. TDM Normal, TDM Left Justified and T= DM=20 > Right Justified. > Without tdm-fsync-half-frame, we purportedly get the following output in = TDM=20 > Normal Mode (I2S Format): > (ch0l =3D channel 0 left, ch0r =3D channel 0 right) > fsync: _____________________________ > \____________________________ > sdi/sdo: ch0l, ch0r, ..., ch3l, ch3r, ch0l, ch0r, ... >=20 > With tdm-fsync-half-frame, we purportedly get the following: >=20 > fsync: _____________________________ > \____________________________ > sdi/sdo: ch0l, ch1l, ch2l, ch3l, ch0r, ch1r, ch2r, ch3r > At least, according to the TRM. I do not have an oscilloscope to verify t= his=20 > myself, and in the following paragraphs, I will elaborate why this seems= =20 > confusing to me. fsync-half-frame is just normal TDM for I2S, the default mode is how DSP mode normally operates. I don't know that there's any pressing need to support mix'n'match here, you could but it should be through the TDM configuration API. > So to answer the question, it's not part of the bus format because it app= lies=20 > to three bus formats, and I'm completely out of my depth here and wouldn'= t=20 > define three separate bus formats based on my own speculation of how this= =20 > works. It is part of the bus format really. I suspect the hardware is the kind that only really implements DSP mode and can just fake up a LRCLK for I2S in order to interoperate. --hUH5gZbnpyIv7Mn4 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmFDN8wACgkQJNaLcl1U h9AhiAf/ZlfcZ9ejEekSn1zn4A88+/ZgbySK7f6ieclZDuSJ0PyYj0x6VN5f+p8U UrfT02ie6+dpCTcQHVQtFcJx5+BN5N8WoBidKDS0gAN3W8R2i9LvWGw8z9wT6tKS KCnSoIL4Gr0ZQ/556y5vIocYG7waZMOckP6/ZuIjBewEH+j0iV34b7uT54kDbfXA JLi2Y6LDveRJbnVsJ4EK4cLgmxHDfjmirUiAjvrWvTcVUXXZDQ1qXalGDFX/ZEFq RzP18+TUX33qEgF1UApmZEIOqSCHst3po+sy1xkpZlOvTzcQAQLaZXMm9PulSx41 Aq2b/PrIEwOcL8Kc4GfCeW9YoGOm3w== =u+Qx -----END PGP SIGNATURE----- --hUH5gZbnpyIv7Mn4--