Subject: [PATCH 3/3] ARM: dts: kirkwood: add kirkwood-km_fixedeth DTS file

From: [email-masked] (Valentin Longchamp)
Date: Thu, 15 May 2014 17:07:48 +0200

On 05/15/2014 03:08 PM, Andrew Lunn wrote:
>> +	i2c at 0 {
>> +		compatible = "i2c-gpio";
>> +		gpios = < &gpio0 8 GPIO_ACTIVE_HIGH		/* sda */
>> +			  &gpio0 9 GPIO_ACTIVE_HIGH>;		/* scl */
>> +		i2c-gpio,delay-us = <2>;	/* ~100 kHz */
>> +	};
> 
> Hi Valentin
> 
> Anything interesting on the i2c bus?

Well yes, but this is then board specific (for all the Keymile variants of the
reference design). Since all these variants are not mainlined, I have added
nothing yet, but this may come later since we are currently reworking our I2C
bus support/topology.

> 
> Does this SoC not have the hardware i2c? I don't see a node for it
> here.
> 

The SoC does have the hardware I2C, but we don't use it and use the above
bitbang one instead. I was not in the company when this was chosen/designed. The
main reason is that the Kirkwood's one is not fast enough (clk < 96 kHz) for our
usage (we have A LOT of different things on this BUS, some must be quick - the
bus speed gets changed from (uuuurrghhh) userpace - and this is a NIGHTMARE,
believe me).

Valentin