Re: [PATCH 1/3] ARM: dts: NSP: Enable SFP on bcm958625hr

[Russell King - ARM Linux]

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.

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