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=-8.2 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=unavailable 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 96596C433B4 for ; Fri, 7 May 2021 15:32:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DAB16113E for ; Fri, 7 May 2021 15:32:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237909AbhEGPdL (ORCPT ); Fri, 7 May 2021 11:33:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:56106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237859AbhEGPdK (ORCPT ); Fri, 7 May 2021 11:33:10 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E3F4B61460; Fri, 7 May 2021 15:32:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620401530; bh=O3zHx8gGy8AU49D+Cnr2TBWRAoXneuMN59DU/Ks3vhs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RjOYIsvAC5gLtDgOeipF0F06gxKKV6y4oHApV4eIapZor+2Jwj5gHQ1ya1MhHIyme bn61u5vsDc+ZcuMPSOH8v51zHMySSD8emcgVya6okdgrrzXFEwxxa//ImRHWGV1gJl sHauyc5dg4V1lXYoUc+almVuAt38m/6XSH8ERigfRMQ7VQWrj8BibB6n8Q5FsVZ/cm kvZ+evUd1a3JB8VP9Zh54XD9EHXQxm4XwVvCPMJ7P1rOOdwGkb7AAM04G8tAH2OFlK 0eu0oPZlAUEz/mqY+wnHxXUmeLJj3RCmP9mID3ZsScJvArFw7MoNkFYFTMyEy+EEP3 QZZHlc+e1zE9A== Date: Fri, 7 May 2021 16:31:32 +0100 From: Mark Brown To: Pratyush Yadav Cc: Tudor Ambarus , Michael Walle , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org Subject: Re: [PATCH 4/6] spi: spi-mem: reject partial cycle transfers in 8D-8D-8D mode Message-ID: <20210507153132.GC6383@sirena.org.uk> References: <20210506191829.8271-1-p.yadav@ti.com> <20210506191829.8271-5-p.yadav@ti.com> <20210507125533.GA6383@sirena.org.uk> <20210507135631.maue7gorfzsv4qpk@ti.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="/e2eDi0V/xtL+Mc8" Content-Disposition: inline In-Reply-To: <20210507135631.maue7gorfzsv4qpk@ti.com> X-Cookie: Postage will be paid by addressee. User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --/e2eDi0V/xtL+Mc8 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 07, 2021 at 07:26:33PM +0530, Pratyush Yadav wrote: > Patches 2 and 3 are a slightly different matter. They add an extra=20 > register write. But most controllers I've come across don't support=20 > 1-byte writes in 8D mode. It is likely that they are sending=20 > bogus/undefined values in the second byte and deasserting CS only after= =20 > the cycle is done. So they should _in theory_ change undefined behaviour= =20 > to defined behaviour. > Still, they introduce an extra register write. I'm not sure how=20 > risk-tolerant you want to be for stable backports. I will leave the=20 > judgement to you or Tudor or Vignesh. Ah, given that if nobody's seeing any issues I'd probably just hold off there TBH. --/e2eDi0V/xtL+Mc8 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmCVXVQACgkQJNaLcl1U h9B8HAf9GZh6wXoQyIjqchDq4kgwLgCdMTMAnT1LjmrcRaeTiLr30MVfyjO+eLan tCZYatA9w4eVKm2NbXI1G0JqZ+ZlmuGlgFEb1kRrSdWn/A6rUF0fHlCjygq6wQTR GBqZ4wWImXKcry+Wc8GsZWggtV7XCkQYE3bp4l2QfXkhFtASgPkSYtLfYbOOKjOP 1Xpc4kqpfpaZIRDPJKqwTykeJaeTxY+T3Lfz/IUjFUa9mtr0RC6FjnA5+ekboY4C pEMICHbnrt2WDRAk6HXqypb5N+HJ2V84XLi3Q/uMjFlgC4+2lLe/OEIkgzGDJns3 8/2LTp0aNJ+CgvTMYbnSmdorhvF2wA== =+ofb -----END PGP SIGNATURE----- --/e2eDi0V/xtL+Mc8--