From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eddie James Subject: Re: [PATCH v10 5/7] i2c: fsi: Add transfer implementation Date: Thu, 5 Jul 2018 13:52:13 -0500 Message-ID: References: <1528918579-27602-1-git-send-email-eajames@linux.vnet.ibm.com> <1528918579-27602-6-git-send-email-eajames@linux.vnet.ibm.com> <20180626023823.i3fmdegn2sric5kx@ninjato> <6713efb9-c4c3-f648-a1e9-7918110091e4@linux.vnet.ibm.com> <20180702182434.5wxxszpgpf6wergl@ninjato> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20180702182434.5wxxszpgpf6wergl@ninjato> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org, benh@kernel.crashing.org, joel@jms.id.au, mark.rutland@arm.com, gregkh@linuxfoundation.org, rdunlap@infradead.org, andy.shevchenko@gmail.com, peda@axentia.se List-Id: devicetree@vger.kernel.org On 07/02/2018 01:24 PM, Wolfram Sang wrote: >>>> + if (msg->flags & I2C_M_RD) >>>> + cmd |= I2C_CMD_READ; >>> Since you support MANGLING, I'd think you can easily support >>> I2C_M_REV_DIR_ADDR here, too? >> Hm, I don't really understand the purpose of that flag. From the docs: >> >> This toggles the Rd/Wr flag. That is, if you want to do a write, but >>     need to emit an Rd instead of a Wr, or vice versa, you set this >>     flag. For example: >> S Addr Rd [A] Data [A] Data [A] ... [A] Data [A] P >> >> I don't think our hardware supports this type of operation. > I'd think something like this should do: > > if (msg->flags & I2C_M_REV_DIR_ADDR) > cmd ^= I2C_CMD_READ; I meant that the hardware cannot interpret this, it would be a meaningless command unfortunately. >