Re: [PATCH 4/5] ARM: novena: Read Ethernet MAC address from EEPROM

[John Watts <contact@jookia.org>]

On Wed, Jan 25, 2023 at 04:42:58PM +0100, Sascha Hauer wrote:
> The barebox PFUZE PMIC driver is not a real regulator driver it's just a
> no-op driver providing a regmap, so by definition it is not guilty.
> 
> My wild guess is that regulator-audio-codec needs to be enabled to let
> the EEPROM work. The Audio codec sits on the same I2C bus as the EEPROM
> and it could be that the codec just pulls the I2C data line low when
> it's not powered up.

Hi Sascha,

I was ignoring my email and troubleshooting further and figured out that
the PMIC driver was a no-op and that for some reason I did need the audio
regulator enabled, but I wasn't sure why.

This makes total sense though.

> 
> You could verify this by doing a
> 
> gpio_direction_output 156 0
> 
> on the command line and then try to read from the EEPROM. It sould fail
> and start working again after a
> 
> gpio_direction_output 156 1

I confirm this was the issue with GPIO 145.

> 
> Sascha

Thanks so much. I'll submit V2 of the Novena patches soon.

John.