[PATCH 1/4] power: regulator: Trigger probe of regulators which are always-on or boot-on

[Marek Vasut]

On 9/11/24 7:57 AM, Svyatoslav Ryhel wrote:

[...]

>>>> You did mention something regarding I2C/PMIC driver probe timing, but it
>>>> seems the I2C driver and PMIC drivers probe roughly around the same time
>>>> in both pass and fail cases ?
>>>
>>> Yes, here I agree that they both probe and probe passes, but I assume
>>> timing of i2c call is critical and there may be some dependency which
>>> is not ready.
>>
>> My guess would be pinmux or clock, maybe the i2c controller is marked as
>> bootph-* in DT and its pinmux/clock is not? Maybe the i2c on tegra works
>> by sheer coincidence right now? Can you have a look?
> 
> Power i2c line (one that hosts PMIC) is configured extremely early in
> SPL since it is needed for cpu and core voltage setup so even if, as
> you say, tegra works by sheer coincidence, specifically this i2c line
> should work non the less, since it has all its pre-requisites (clock
> and pinmux) configured on early stage.

Is it possible that this configuration is somehow reset or reconfigured 
from DT early on in U-Boot proper ?

Do you have serial console output in board_f.c time in U-Boot proper , 
possibly using DEUBG_UART , to check if there might be some prior 
failing I2C transfer at that board_f.c time ?

> As I have told, I was not able to determine exact reason why this
> happens, it should not and yet it does. This is why I have abandoned
> my attempt to implement same changes you are currently proposing.

If tegra has a problem, it should be fixed on tegra side and not block 
core plumbing. I am not seeing the problem on stm32 or imx systems, so I 
am banking toward tegra-specific issue.

Are you able to debug this ?