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=-5.6 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 1DCCFC56202 for ; Mon, 9 Nov 2020 14:14:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B53BD2076E for ; Mon, 9 Nov 2020 14:14:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604931279; bh=kLJzaopBrWpFidVU7xRvPTiQ3M4h0ap58VBp21YzxYs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=B93m668Lio2YNthjNLvW63qAYmIAE/rKpckq4yrFuycitMpYoHpeZQiqUfT1278kK g6Z7yVYxTDA6lUru5f+4LO64tE6PNwRyanQYc1YvG0Hz8ExHDm0cgMJqvhUOc4Co8f 1G5Rl4dzg3YOFfo2mT2QEpkz2NZSeoHBN90X76Wg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730932AbgKIOOi (ORCPT ); Mon, 9 Nov 2020 09:14:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:47768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730904AbgKIOOh (ORCPT ); Mon, 9 Nov 2020 09:14:37 -0500 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 30B79206ED; Mon, 9 Nov 2020 14:14:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604931276; bh=kLJzaopBrWpFidVU7xRvPTiQ3M4h0ap58VBp21YzxYs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Jb8Tfl/071h1BNkQ95G0MdcMqzm0ItDQ91+UFxaDdcTP/Hn4YNNpN3L99eqPfm1eE iTtKIyIl30zgvi2L/4YXmciVZ5xR/lk9i9XeWhcEx7rqBAE3OSbNOiS8IGnLwAhJuR mYM+oWmy3+Hzzxh9jMiJiyv0s+Mz/Ziy5SENX1Ek= Date: Mon, 9 Nov 2020 14:14:22 +0000 From: Mark Brown To: Sean Anderson Cc: Damien Le Moal , Palmer Dabbelt , linux-riscv@lists.infradead.org, Rob Herring , Frank Rowand , devicetree@vger.kernel.org, Serge Semin , linux-spi@vger.kernel.org, Stephen Boyd , linux-clk@vger.kernel.org, Linus Walleij , linux-gpio@vger.kernel.org, Philipp Zabel Subject: Re: [PATCH 03/32] spi: dw: Fix driving MOSI low while recieving Message-ID: <20201109141422.GD6380@sirena.org.uk> References: <20201107081420.60325-1-damien.lemoal@wdc.com> <20201107081420.60325-4-damien.lemoal@wdc.com> <20201109132935.GB6380@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="5p8PegU4iirBW1oA" Content-Disposition: inline In-Reply-To: X-Cookie: This fortune is false. User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org --5p8PegU4iirBW1oA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Nov 09, 2020 at 08:47:10AM -0500, Sean Anderson wrote: > On 11/9/20 8:29 AM, Mark Brown wrote: > > In this case it also looks like the controller hardware requires > > transmit data and therefore should be setting SPI_MUST_TX and just > > removing the in driver default anyway, though that will have no effect > > one way or anther on the issue you're seeing. > There is a recieve-only mode, but it is not used by this driver. Perhaps > it should be. I'd expect it'd perform better, especially on systems that are apparently struggling for CPU bandwidth like yours seems to. > > Please also try to avoid the use of master/slave terminology where > > reasonable, controller and device tend to work for SPI (though MOSI/MISO > > are going to be harder to shift). > Here I use it to draw distinction between the SPI master and the SPI > slave, which are both devices in different contexts.=20 If you find the use of device to refer to the device being controlled confusing consider also using something like client device instead, there's a number of ways to do it (there's a list in Documentation IIRC). --5p8PegU4iirBW1oA Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl+pTr4ACgkQJNaLcl1U h9DamAf9GViNS0tl9IE38rF2GQEVHH0m8fIjSSQYDUg/HaV3KWTlgA+RxBct/6Su 0kWc3OyLDS0kbdA70oliL0kA+AQEbPnvxx6W3ktbW9HvGbf03yPhlVayBdx9QxZJ Gz2eWEe05CPdrQwMEo8LnjrfeL1uycSgalHjDbotqu2DBbcrvHoZkt8bL5+0EdcH a0MP1HmvpfvX+l36JPx8m6kOay+2cXYcQwIJ8FMV6rOZXpmgdlpT9UTTqMnUji8V BFLLRgEaNi6WG8WXhB8pm3o/z9w2ukz62EPCkeNEGB36a6WI8D9zxSNQ6bM/ZszD wqk4bWzbFhknKP96ou7EqTa6wlbLqg== =+WcS -----END PGP SIGNATURE----- --5p8PegU4iirBW1oA--