[PATCH v6 05/12] power-domain: Add refcounting

[Wadim Egorov]

Am 16.04.25 um 12:50 schrieb Neha Malcom Francis:
> Hi Miquel
> 
> On 16/04/25 14:36, Miquel Raynal wrote:
>> Hello,
>>
>>>>> -int power_domain_on(struct power_domain *power_domain)
>>>>> +int power_domain_on_lowlevel(struct power_domain *power_domain)
>>>>>   {
>>>>> +	struct power_domain_priv *priv = dev_get_uclass_priv(power_domain->dev);
>>>>>   	struct power_domain_ops *ops = power_domain_dev_ops(power_domain->dev);
>>>>> +	int ret;
>>>>>   
>>>>>   	debug("%s(power_domain=%p)\n", __func__, power_domain);
>>>>>   
>>>>> -	return ops->on ? ops->on(power_domain) : 0;
>>>>> +	if (priv->on_count++ > 0)
>>>>> +		return -EALREADY;
>>>>
>>>> This change is broken for power domain providers with #power-domain-cells = <1>,
>>>> which can have multiple domains per provider device. There would need to be a
>>>> separate reference count per domain, and currently the uclass doesn't know the
>>>> range of valid domain IDs.
>>>
>>> I didn't see this reply earlier, would've saved some time debugging to
>>> come to the same conclusion :) but yes this is the reason for
>>> breaking.
>>
>> That's indeed the reason, thanks a lot for figuring this out. I am
>> looking for a solution. I can reproduce on imx8mp by enabling the two
>> LCD interfaces, as they have a similar pattern as on k3 platform: a
>> single power domain node and one cell for figuring out which PD to
>> enable.
>>
>> The uclass does not save any data, so I don't have an immediate fix to
>> propose. Let me dig a bit more into that and find a solution.
>>
> 
> Thanks!
> 
> Meanwhile, could we revert this patch to keep the platforms from breaking?

Would be nice, just took me the same route to pin this commit and find 
out about this discussion. I think more people will run into the same 
issue soon

> 
> 
>> Thanks,
>> Miquèl
>