On 25.01.23 14:31, John Watts wrote:
> 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 = <®_vgen6>;
regulator-fixed only understands vin-supply.
> };
>
> But Barebox doesn't seem to see the 'regulator-always-on' as
> 'start immediately'.
For this to work we'd need:
of_devices_ensure_probed_by_property("regulator-always-on");
of_devices_ensure_probed_by_property("regulator-boot-on");
somewhere in generic code. Currently, these properties are only
consulted when the device is actually probed.
I actually updated the eeprom node to use
> reg_3p3v as vcc-supply and things were still probed in the wrong order.
That's odd. You can enable CONFIG_DEBUG_PROBES to see in what order
probes happened and at what depth (each probe within a probe is
indented more than its parent).
Cheers,
Ahmad
>
> John.
>
>
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