linux-kernel - Re: [PATCH v3 3/5] PCI/pwrctrl: Skip scanning for the device further if pwrctrl device is created

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Message-ID: <20250220233520.GA319453@bhelgaas>
Date: Thu, 20 Feb 2025 17:35:20 -0600
From: Bjorn Helgaas <helgaas@...nel.org>
To: manivannan.sadhasivam@...aro.org
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
	Bartosz Golaszewski <brgl@...ev.pl>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH v3 3/5] PCI/pwrctrl: Skip scanning for the device further
 if pwrctrl device is created

On Thu, Jan 16, 2025 at 07:39:13PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> 
> The pwrctrl core will rescan the bus once the device is powered on. So
> there is no need to continue scanning for the device further.

> -/*
> - * Create pwrctrl device (if required) for the PCI device to handle the power
> - * state.
> - */
> -static void pci_pwrctrl_create_device(struct pci_bus *bus, int devfn)
> +static struct platform_device *pci_pwrctrl_create_device(struct pci_bus *bus, int devfn)

> +	 * Create pwrctrl device (if required) for the PCI device to handle the
> +	 * power state. If the pwrctrl device is created, then skip scanning
> +	 * further as the pwrctrl core will rescan the bus after powering on
> +	 * the device.

I know you only moved the first sentence, but I think "power state" is
likely to be confused with the D0, D1, D2, D3hot, D3cold power
management states.  Maybe we could reword this to talk about power
control, power sequencing, power supplies, power regulators or
something?

> +	 */
> +	if (pci_pwrctrl_create_device(bus, devfn))
> +		return NULL;
>  
>  	if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000))
>  		return NULL;
> 
> -- 
> 2.25.1
> 
>