[RFC PATCH] power: regulator: Avoid probing of regulators at pre-ram stage

[Jonas Karlman]

Hi Udit and Quentin,

On 2025-02-21 14:54, Quentin Schulz wrote:
> Hi Udit,
> 
> On 2/21/25 1:45 PM, Udit Kumar wrote:
>> commit 51c4679d2f84 ("power: regulator: Trigger probe of regulators which are always-on or boot-on")
>> allow always on and boot on regulators to be early probed.
>> Due to this probing boot time increases.
>> Since in hardware regulators are always on, so probing of such
> 
> According to the DT binding:
> 
> - regulator-always-on only means it should never be disabled, not that 
> it's automatically enabled.
> 
> - regulator-boot-on means "It's expected that this regulator was left on 
> by the bootloader." We're the bootloader so it's our duty to turn the 
> regulator on.
> 
> So I'm not sure the justification is valid here.
> 
> I vaguely remember this patch was discussed a lot between Marek, Simon 
> and possibly Caleb so let's see if they have something to say.

Correct, this cannot be reverted or it will break platforms that used to
call regulators_enable_boot_on(), see commit 6f52feee2867 ("power:
regulator: Drop regulators_enable_boot_on/off()").

If you want to skip probe, please ensure that appropriate bootph- props
is used so that the regulator is excluded from your platform pre-ram
phase.

Regards,
Jonas

> 
> Cheers,
> Quentin