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=-4.1 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 A80A7C2D0A3 for ; Wed, 4 Nov 2020 10:35:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3EA1521734 for ; Wed, 4 Nov 2020 10:35:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604486139; bh=wAgrnJv0Y8O8Q8w96HJSFnamkXIXbNsF0cRRMzjiJos=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ZRP1fGIQia19Qnt8kh3AXe1x+1npQHkjkwD7NTD83zUEY8ip7lRNGUxNbXAjYe5eX tt+2lpH4vPgvidFu4ciijdyf/SGilUQ/uST5q3pQB+PZfBGrljtLTjMLKv4g/yoFFy dTWFS2oiCKsVMUTAlwtib8JLoT0p81EaBiYFWg+g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726410AbgKDKfi (ORCPT ); Wed, 4 Nov 2020 05:35:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:60938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726323AbgKDKfi (ORCPT ); Wed, 4 Nov 2020 05:35:38 -0500 Received: from localhost (p54b3309e.dip0.t-ipconnect.de [84.179.48.158]) (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 A25CD2072C; Wed, 4 Nov 2020 10:35:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604486137; bh=wAgrnJv0Y8O8Q8w96HJSFnamkXIXbNsF0cRRMzjiJos=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jy8Z9WrgEhPJ+Lo3CO62HKjjn0KLyvApe3e3B4GK9LR/KZ0Q4y0ogREVwgTVWQxnu LcF+d7trNR3u6wsFbYrhnIxXl+r7WRYqF+pC0xjfhS/3apZTo+qIaVtfWpk1rHXckO wOSLO9mjTM6EzKxaDJf3yTLsTRlScgqwxMI5TlOY= Date: Wed, 4 Nov 2020 11:35:31 +0100 From: Wolfram Sang To: Michael.Wu@vatics.com Cc: jarkko.nikula@linux.intel.com, andriy.shevchenko@linux.intel.com, mika.westerberg@linux.intel.com, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, morgan.chang@vatics.com Subject: Re: [PATCH 2/2] i2c: designware: slave should do WRITE_REQUESTED before WRITE_RECEIVED Message-ID: <20201104103531.GA3984@ninjato> References: <20201030080420.28016-1-michael.wu@vatics.com> <20201030080420.28016-3-michael.wu@vatics.com> <20201103210349.GE1583@kunai> <5DB475451BAA174CB158B5E897FC1525B1295560@MBS07.vivotek.tw> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="W/nzBZO5zC0uMSeA" Content-Disposition: inline In-Reply-To: <5DB475451BAA174CB158B5E897FC1525B1295560@MBS07.vivotek.tw> Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org --W/nzBZO5zC0uMSeA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > Not exactly. There're an interrupt state name "RD_REQ" but no one named > like "WR_REQ". >=20 > For read-request, the slave will get a RD_REQ interrupt.=20 > For write-request, the slave won't be interrupted until data arrived to > trigger interrupt "RX_FULL". >=20 > I tried to use GPIO to simulate an I2C master. I only sent its own > address + W bit without any data and then I got only a STOP_DET interrupt. > If I sent its own address + W bit + one byte data and then I got one > RX_FULL and a STOP_DET. >=20 > It seems the controller doesn't interrupt when RW bit is W, but R does. Thanks for the detailed explanation! Okay, then what you do looks correct to me (from a high level perspective without really knowing the HW): when RX is full, you first send the state WRITE_REQUESTED when there is no other transfer on-going. Then you send WRITE_RECEIVED immediately. I think this is the way to do it. --W/nzBZO5zC0uMSeA Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAl+ig+8ACgkQFA3kzBSg KbasRhAAjD4nGj2H2f7HEpuc0N6DG+ylX22AblwdraC6uDmLYH9uBcWlpAC+Hm21 BnABcvEeq6Bo4PdjoNQa5wtKOPkwWqtYFngWlFMMJBMpwgiGe+TFDNduspLxQHa3 TPmmBDITU5gdHOOifjr6XmdHnoMw47fiLqt5fxsRVHxrPoJBkicAT3wkmg/KCKms AdOKX9bloPoInFUlp/XIsVwxiDobTx6/OWPX1p6wecOFu2Uf1+xpdC+3dXzVvjnW SE+22AwoFtDwujSrmQPIRSMGQ2uoVX7i5ibIBJaDrShRguYwEz2Y+/K69b17CBy5 YcAH4e4YHt7dUy9WJGhrlJ71A1ssNRdKWHKxZbw2s64q4T2UPQZZZtj8sVGz5dCI O9tOaLGt9ZdIdesWiygsVmf119RWYX7T0/TKfZ1ps7dlG4A53gLz82UNw70Frguh 39ypPw4XJKqdi0RGuzbGjM1WcvSPoO6a16kKsIFZrnHO1VfAlfTq6PEo0kbd9m4s wSm8jHWtufXIlpDtzJkR2MuQj/j0O5H6P7co7bF2ai07hH9nury5ZCvSt0bkkDmH o7iy2s1KHm7IBy05JIhk+ThTxjFtbX46uyuxrURMbosPiZR2Lh9tmnsW84SFwRAX u9Zwrhtz3N6aVQmu4DEpm+J6KipyCz8uyePm509cAEB7nt6OTiY= =Gnqr -----END PGP SIGNATURE----- --W/nzBZO5zC0uMSeA--