Re: [PATCH 1/2] PCI/pwrctrl: Ensure that the remote endpoint node parent has the supply requirement

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

On 2/17/2026 3:48 PM, Manivannan Sadhasivam via B4 Relay wrote:
> From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
>
> If OF graph is used in the PCI device node, pwrctrl core currently creates
> the pwrctrl device even if the remote endpoint doesn't have the power
> supply requirements. Since the device doesn't have any power supply
> requirements, there was no pwrctrl driver to probe, leading to PCI
> controller driver probe deferral as it waits for all pwrctrl drivers to
> probe before starting bus scan.
>
> This issue happens with Qcom ath12k devices with WSI interface attached to
> the Qcom IPQ platforms.
>
> Fix this issue by checking for the existence of at least one power supply
> property in the remote endpoint parent node. To consolidate all the checks,
> create a new helper pci_pwrctrl_is_required() and move all the checks
> there.
>
> Fixes: 9db826206f9b ("PCI/pwrctrl: Create pwrctrl device if graph port is found")
> Reported-by: Raj Kumar Bhagat <raj.bhagat@oss.qualcomm.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Reviewed-by: Krishna Chaitanya Chundru<krishna.chundru@oss.qualcomm.com>

- Krishna Chaitanya.
> ---
>   drivers/pci/pwrctrl/core.c | 47 +++++++++++++++++++++++++++++++++-------------
>   1 file changed, 34 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
> index 6f7dea6746e0..8325858cc379 100644
> --- a/drivers/pci/pwrctrl/core.c
> +++ b/drivers/pci/pwrctrl/core.c
> @@ -268,6 +268,39 @@ int pci_pwrctrl_power_on_devices(struct device *parent)
>   }
>   EXPORT_SYMBOL_GPL(pci_pwrctrl_power_on_devices);
>   
> +/*
> + * Check whether the pwrctrl device really needs to be created or not. The
> + * pwrctrl device will only be created if the node satisfies below requirements:
> + *
> + * 1. Presence of compatible property to match against the pwrctrl driver (AND)
> + * 2. At least one of the power supplies defined in the devicetree node of the
> + *    device (OR) in the remote endpoint parent node to indicate pwrctrl
> + *    requirement.
> + */
> +static bool pci_pwrctrl_is_required(struct device_node *np)
> +{
> +	struct device_node *endpoint;
> +
> +	if (!of_property_present(np, "compatible"))
> +		return false;
> +
> +	if (of_pci_supply_present(np))
> +		return true;
> +
> +	if (of_graph_is_present(np)) {
> +		for_each_endpoint_of_node(np, endpoint) {
> +			struct device_node *remote __free(device_node) =
> +				of_graph_get_remote_port_parent(endpoint);
> +			if (remote) {
> +				if (of_pci_supply_present(remote))
> +					return true;
> +			}
> +		}
> +	}
> +
> +	return false;
> +}
> +
>   static int pci_pwrctrl_create_device(struct device_node *np,
>   				     struct device *parent)
>   {
> @@ -287,19 +320,7 @@ static int pci_pwrctrl_create_device(struct device_node *np,
>   		return 0;
>   	}
>   
> -	/*
> -	 * Sanity check to make sure that the node has the compatible property
> -	 * to allow driver binding.
> -	 */
> -	if (!of_property_present(np, "compatible"))
> -		return 0;
> -
> -	/*
> -	 * Check whether the pwrctrl device really needs to be created or not.
> -	 * This is decided based on at least one of the power supplies defined
> -	 * in the devicetree node of the device or the graph property.
> -	 */
> -	if (!of_pci_supply_present(np) && !of_graph_is_present(np)) {
> +	if (!pci_pwrctrl_is_required(np)) {
>   		dev_dbg(parent, "Skipping OF node: %s\n", np->name);
>   		return 0;
>   	}
>