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

[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?


> Thanks,
> Miquèl

-- 
Thanking You
Neha Malcom Francis