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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 977A0C11F66 for ; Tue, 29 Jun 2021 11:11:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75D7661DD4 for ; Tue, 29 Jun 2021 11:11:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233337AbhF2LNv (ORCPT ); Tue, 29 Jun 2021 07:13:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:56010 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233329AbhF2LNu (ORCPT ); Tue, 29 Jun 2021 07:13:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id DBE9261DC7; Tue, 29 Jun 2021 11:11:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624965083; bh=qR7dpwEkDa37N8fq1JF+niB5xx9wYkD8oDf8aWqJvS8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gsv0XlgkoGrCqUJuMrRL6ilJXwxyc5UDgKzptH+i1jtOVWAzGXi5L3+KFbOJGNENQ qX0bQ8ZFEkb3ecE6dT1/EIsDi4WRRLRoUxRRKJiqlLw+U7tCjDtroMdIJFrM3N21lm ZBcC12OTfBFFPZNNrz9eqk6NGZD4jJ8GtEGnV/vJgGDPRn8AJrBbv9N3vb3h0Pm/3A 2HOfIoQkUzwW2IAIe3MSSDAVs754SRfQUjgws1BHg1kYkmSqe3sAL+T1uFFRYyAdNV EQC6bhJsu67vkUA4vCn5iIZB/+Kuzh3CK+J2qKooOeWSZhUPJhbGLgSaN2MSPEs1Pj 6TYUx3ManeaoA== Date: Tue, 29 Jun 2021 13:11:20 +0200 From: Wolfram Sang To: Viresh Kumar Cc: Jie Deng , linux-i2c@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, mst@redhat.com, jasowang@redhat.com, andriy.shevchenko@linux.intel.com, conghui.chen@intel.com, arnd@arndb.de, kblaiech@mellanox.com, jarkko.nikula@linux.intel.com, Sergey.Semin@baikalelectronics.ru, rppt@kernel.org, loic.poulain@linaro.org, tali.perry1@gmail.com, u.kleine-koenig@pengutronix.de, bjorn.andersson@linaro.org, yu1.wang@intel.com, shuo.a.liu@intel.com, stefanha@redhat.com, pbonzini@redhat.com Subject: Re: [PATCH v10] i2c: virtio: add a virtio i2c frontend driver Message-ID: Mail-Followup-To: Wolfram Sang , Viresh Kumar , Jie Deng , linux-i2c@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, mst@redhat.com, jasowang@redhat.com, andriy.shevchenko@linux.intel.com, conghui.chen@intel.com, arnd@arndb.de, kblaiech@mellanox.com, jarkko.nikula@linux.intel.com, Sergey.Semin@baikalelectronics.ru, rppt@kernel.org, loic.poulain@linaro.org, tali.perry1@gmail.com, u.kleine-koenig@pengutronix.de, bjorn.andersson@linaro.org, yu1.wang@intel.com, shuo.a.liu@intel.com, stefanha@redhat.com, pbonzini@redhat.com References: <226a8d5663b7bb6f5d06ede7701eedb18d1bafa1.1616493817.git.jie.deng@intel.com> <20210629101627.kwc2rszborc3kvjs@vireshk-i7> <20210629103014.nlk3mpetydc4mi6l@vireshk-i7> <20210629105649.nt63mxtiy6u7de3g@vireshk-i7> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="sAaNsJX8TpQmVU+g" Content-Disposition: inline In-Reply-To: <20210629105649.nt63mxtiy6u7de3g@vireshk-i7> Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org --sAaNsJX8TpQmVU+g Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > The case when ``length of \field{write_buf}''=3D0, and at the same time, > ``length of \field{read_buf}''=3D0 is called not-a-read-write request > and result for such a request is I2C device specific. Obviously, I don't know much about the specs and their wording. Still I wonder if we can't call it a zero length transfer? This is allowed by the I2C standard and SMBus has even a proper name for it (SMBUS_QUICK). =46rom my point of view, I would not say it is device specific because devices are expected to ACK such a message. --sAaNsJX8TpQmVU+g Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAmDa/9gACgkQFA3kzBSg Kba1Jw//QCapndYVkCEmAxCDb4OuBgOzHn/nM06PE9m2MBtPSuR+dRU98n47Bmay 3VQASHJA+ZydINhHEbMhgClGxDs/jnLV1vx20XraVPzwKLrHG9UDv5dVJCmY6YZq 3F7GV7bIrbPtFVxDt0d0OjEmDcmSHxG/HQeiVwWKDC+RB/5Ono2oemIN/mrmafqZ vP2Pf46cbQNMHbcgOPG8GxFI6jUtVvPB/xXHAf0TA2U/DzuxIbNH69ymhE57VMV2 ZEQFy+/am9LnhNWbcoaaJCSjVps2e7JqS4en7LOIAexdZGJkNQmog/qZNPmZZkVu XY0eLGKS2erq94vh6Wp76VKwRLhG/T2rwkFQxFdzHK89otRcfhHRBr9bMtKdkxkw bihc4FqiM4NiejvF0b+wDDGXSLXnT1UNUuyQ8MYHHxl+2bjTEKBajqBL2bzlege4 upHspbvf/8L3HRlF0UVG01exPBpeUAeiFDM7imoQL6g7Q2itMcYnB0zhxABXZKYm xNGbmdd8mftRCnxlYV1qyCYFxACYnrIQAY70d9IaLHjaKEpG2XeHEpMWEopG52Fk M4K/JXnhae3vwVCl1ya5aRpMbIZK6wNzyPewXe0FqdZ8NnlITgxyJImPJI2WBy5p OBV3Bghg0b/L8vlgFPJP5QLcOY4KjF2VmKBy7Tw/4nB3oxVDihU= =hGo0 -----END PGP SIGNATURE----- --sAaNsJX8TpQmVU+g--