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

[John Watts <contact@xxxxxxxxxx>]

On Wed, Jan 25, 2023 at 09:19:23AM +0100, Sascha Hauer wrote:
> Yes, normally it should be set up already, unless of course there is
> some needed pinctrl configuration in an unrelated device tree node.
> 
> Sascha

Hi Sascha,

Here's what I think is going on:

- The I2C line requires 3v3_DELAYED for pull-ups
- The EEPROM requires 3v3_DELAYED for power
- 3v3_DELAYED requires VGEN5 from the PMIC (acts as a gate)
- The PMIC is loaded after the EEPROM

Most things on the board require these delayed rails, so I'm wondering
what the approach should be here. Should I:

- Rewrite the device tree to reference these delayed rails
- Probe the PMIC first

I did try this:

	reg_3p3v: regulator-3p3v {
		compatible = "regulator-fixed";
		regulator-name = "3P3V_DELAYED";
		regulator-min-microvolt = <3300000>;
		regulator-max-microvolt = <3300000>;
		regulator-always-on;
		gate-supply = <&reg_vgen6>;
	};

But Barebox doesn't seem to see the 'regulator-always-on' as
'start immediately'. I actually updated the eeprom node to use
reg_3p3v as vcc-supply and things were still probed in the wrong order.

John.