From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH v11 5/8] i2c: fsi: Add transfer implementation Date: Wed, 11 Jul 2018 09:39:15 +1000 Message-ID: References: <1530816030-13010-1-git-send-email-eajames@linux.vnet.ibm.com> <1530816030-13010-6-git-send-email-eajames@linux.vnet.ibm.com> <20180709224114.4h47enyt4tucqcou@ninjato> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Eddie James , Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.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 Tue, 2018-07-10 at 12:52 -0500, Eddie James wrote: > > On 07/09/2018 05:41 PM, Wolfram Sang wrote: > > > + cmd |= FIELD_PREP(I2C_CMD_ADDR, msg->addr >> 1); > > > > I just noticed this and wonder: Don't you need the LSB of the address? > > It is not the RW flag, this is encoded in msg->flags. > > So, the hardware interprets the LSB as the RW flag. It wouldn't be > possible to have a device addressed with the LSB set on this I2C master. What do you mean ? That doesn't sound right... > > > > > Also, no seperate handling for 10 bit addresses? Technically, 7-bit 0x50 > > is different on the wire from 10-bit 0x050. This is minor, though. There > > are no 10-bit devices out there. Still, did you test 10-bit support? > > Indeed, real 10-bit addresses require some additional manipulation of > this I2C master in order to work. We don't support it right now. > > Thanks, > Eddie > > > > > Rest looks good. > >