From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH 1/3] ARM: dts: NSP: Enable SFP on bcm958625hr Date: Mon, 27 Aug 2018 23:26:46 +0100 Message-ID: <20180827222646.GF30658@n2100.armlinux.org.uk> References: <20180827200344.16158-1-f.fainelli@gmail.com> <20180827200344.16158-2-f.fainelli@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180827200344.16158-2-f.fainelli@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Florian Fainelli Cc: linux-arm-kernel@lists.infradead.org, Rob Herring , Mark Rutland , Ray Jui , Scott Branden , Jon Mason , "maintainer:BROADCOM IPROC ARM ARCHITECTURE" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list , andrew@lunn.ch List-Id: devicetree@vger.kernel.org On Mon, Aug 27, 2018 at 01:03:42PM -0700, Florian Fainelli wrote: > Enable the SFP connected to port 5 of the switch and wire up all GPIOs > to the SFP cage. Because of a hardware limitation of the i2c controller > on the iProc SoCs which prevents large i2c (> 256 bytes) transactions to > work, we use the i2c-gpio interface instead, which does not have that > limitation. This allows us to read the SFP module EEPROM, which would > not be possible otherwise since it exceeds that size during a single > read transfer. We shouldn't exceed 256 bytes, since 256 bytes is the "page" size of the EEPROM. The most that we read in one block is either ETH_MODULE_SFF_8079_LEN or (ETH_MODULE_SFF_8472_LEN - ETH_MODULE_SFF_8079_LEN), both of which result in no more than 256 byte reads. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up According to speedtest.net: 13Mbps down 490kbps up