Re: [PATCH 1/3] ARM: dts: NSP: Enable SFP on bcm958625hr
From: Russell King - ARM Linux <linux@armlinux.org.uk>
Date: 2018-08-27 22:27:11
Also in:
linux-arm-kernel, lkml
From: Russell King - ARM Linux <linux@armlinux.org.uk>
Date: 2018-08-27 22:27:11
Also in:
linux-arm-kernel, lkml
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