[BUG] Error applying setting, reverse things back on lot of devices

[Ahmad Fatoum]

Hello Michał,

CC += linux-stm32

On 10/24/20 1:53 PM, Michał Mirosław wrote:
> On Fri, Oct 23, 2020 at 10:39:43PM +0200, Corentin Labbe wrote:
>> On Fri, Oct 23, 2020 at 03:42:01PM +0200, Corentin Labbe wrote:
>>> On Wed, Oct 21, 2020 at 08:31:49PM +0200, Corentin Labbe wrote:
>>> I have just saw thoses 3 lines which are probably the real problem.
>>> I have started a new bisect with this error, but it is hitting the same "crash range" the first one.
>>>
>>
>> I have bisected the problem to commit aea6cb99703e17019e025aa71643b4d3e0a24413 ("regulator: resolve supply after creating regulator")
>> Reverting this fix my problem.

The change broke boot on all the STM32MP1 boards, because the STPMIC driver
has a vref_ddr regulator, which does not have a dedicated supply, but without
a vref_ddr-supply property the system now no longer boots.

> Can you try the hack below?
> 
> Best Regards,
> Michał Mirosław
> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index a4ffd71696da..9ad091f5f1ab 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -1169,6 +1169,9 @@ static int machine_constraints_voltage(struct regulator_dev *rdev,
>  		}
>  
>  		if (current_uV < 0) {
> +			if (current_uV == -EINVAL && rdev->supply_name)
> +				return -EPROBE_DEFER;
> +

This doesn't fix the issue for the STM32MP1 boards (tested on LXA MC-1).
Seeing that the patch is already in stable, I think this patch should be
reverted until the issues are solved in Linus' master.

Cheers,
Ahmad


>  			rdev_err(rdev,
>  				 "failed to get the current voltage: %pe\n",
>  				 ERR_PTR(current_uV));
> 
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> 

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