Re: [PATCH V4 2/8] PCI: imx6: Add skip_pwrctrl_off flag support

Re: [PATCH V4 2/8] PCI: imx6: Add skip_pwrctrl_off flag support

[Bjorn Helgaas]

[+cc Mediatek folks]

On Tue, Jun 30, 2026 at 06:31:33PM +0800, Sherry Sun (OSS) wrote:
> From: Sherry Sun <sherry.sun@nxp.com>
> 
> Use dw_pcie_rp::skip_pwrctrl_off to avoid powering off devices during
> suspend to preserve wakeup capability of the devices and also not to power
> on the devices in the init path.

Only pci-imx6.c, pcie-qcom.c, and pcie-mediatek-gen3.c use
pci-pwrctrl.  pcie-qcom.c already has similar skip_pwrctrl_off checks,
but pcie-mediatek-gen3.c does not.  Does it need them?

> This allows controller power-off to be skipped when some devices(e.g. M.2
> cards key E without auxiliary power) required to support PCIe L2 link state
> and wake-up mechanisms.
> 
> Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 21 ++++++++++++++-------
>  1 file changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 1b535bb6fd31..0685573fee71 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1382,10 +1382,12 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
>  		}
>  	}
>  
> -	ret = pci_pwrctrl_power_on_devices(dev);
> -	if (ret) {
> -		dev_err(dev, "failed to power on pwrctrl devices\n");
> -		goto err_reg_disable;
> +	if (!pp->skip_pwrctrl_off) {
> +		ret = pci_pwrctrl_power_on_devices(dev);
> +		if (ret) {
> +			dev_err(dev, "failed to power on pwrctrl devices\n");
> +			goto err_reg_disable;
> +		}
>  	}
>  
>  	ret = imx_pcie_clk_enable(imx_pcie);
> @@ -1454,7 +1456,8 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
>  err_clk_disable:
>  	imx_pcie_clk_disable(imx_pcie);
>  err_pwrctrl_power_off:
> -	pci_pwrctrl_power_off_devices(dev);
> +	if (!pp->skip_pwrctrl_off)
> +		pci_pwrctrl_power_off_devices(dev);
>  err_reg_disable:
>  	if (imx_pcie->vpcie)
>  		regulator_disable(imx_pcie->vpcie);
> @@ -1473,7 +1476,8 @@ static void imx_pcie_host_exit(struct dw_pcie_rp *pp)
>  	}
>  	imx_pcie_clk_disable(imx_pcie);
>  
> -	pci_pwrctrl_power_off_devices(pci->dev);
> +	if (!pci->pp.skip_pwrctrl_off)
> +		pci_pwrctrl_power_off_devices(pci->dev);
>  	if (imx_pcie->vpcie)
>  		regulator_disable(imx_pcie->vpcie);
>  }
> @@ -1990,11 +1994,14 @@ static int imx_pcie_probe(struct platform_device *pdev)
>  static void imx_pcie_shutdown(struct platform_device *pdev)
>  {
>  	struct imx_pcie *imx_pcie = platform_get_drvdata(pdev);
> +	struct dw_pcie *pci = imx_pcie->pci;
> +	struct dw_pcie_rp *pp = &pci->pp;
>  
>  	/* bring down link, so bootloader gets clean state in case of reboot */
>  	imx_pcie_assert_core_reset(imx_pcie);
>  	imx_pcie_assert_perst(imx_pcie, true);
> -	pci_pwrctrl_power_off_devices(&pdev->dev);
> +	if (!pp->skip_pwrctrl_off)
> +		pci_pwrctrl_power_off_devices(&pdev->dev);
>  	pci_pwrctrl_destroy_devices(&pdev->dev);
>  }
>  
> -- 
> 2.50.1
> 

RE: [PATCH V4 2/8] PCI: imx6: Add skip_pwrctrl_off flag support

[Sherry Sun]

> Subject: Re: [PATCH V4 2/8] PCI: imx6: Add skip_pwrctrl_off flag support
> 
> [+cc Mediatek folks]
> 
> On Tue, Jun 30, 2026 at 06:31:33PM +0800, Sherry Sun (OSS) wrote:
> > From: Sherry Sun <sherry.sun@nxp.com>
> >
> > Use dw_pcie_rp::skip_pwrctrl_off to avoid powering off devices during
> > suspend to preserve wakeup capability of the devices and also not to
> > power on the devices in the init path.
> 
> Only pci-imx6.c, pcie-qcom.c, and pcie-mediatek-gen3.c use pci-pwrctrl.  pcie-
> qcom.c already has similar skip_pwrctrl_off checks, but pcie-mediatek-gen3.c
> does not.  Does it need them?

I think that's depends on if the controller have the usercases such as M.2 keyE
connector without auxiliary power and required to support PCIe L2 link state
and wake-up mechanisms.

Best Regards
Sherry