Re: [PATCH 1/8] PCI: imx6: Add skip_pwrctrl_off flag support

[Frank Li <Frank.li@oss.nxp.com>]

On Thu, Jun 18, 2026 at 06:10:40PM +0800, Sherry Sun (OSS) wrote:
> From: Sherry Sun <sherry.sun@nxp.com>
>
> Use dw_pcie::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.
> 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 | 36 +++++++++++++++++----------
>  1 file changed, 23 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 0fa716d1ed75..ff5a9565dbbf 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1382,16 +1382,20 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
>  		}
>  	}
>
> -	ret = pci_pwrctrl_create_devices(dev);
> -	if (ret) {
> -		dev_err(dev, "failed to create pwrctrl devices\n");
> -		goto err_reg_disable;
> +	if (!pci->suspended) {
> +		ret = pci_pwrctrl_create_devices(dev);
> +		if (ret) {
> +			dev_err(dev, "failed to create pwrctrl devices\n");
> +			goto err_reg_disable;
> +		}

supposed create_devices only do once.

pci_pwrctrl_power_on_devices() controller on and off for difference case.

Frank
>  	}
>
> -	ret = pci_pwrctrl_power_on_devices(dev);
> -	if (ret) {
> -		dev_err(dev, "failed to power on pwrctrl devices\n");
> -		goto err_pwrctrl_destroy;
> +	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_pwrctrl_destroy;
> +		}
>  	}
>
>  	ret = imx_pcie_clk_enable(imx_pcie);
> @@ -1460,9 +1464,10 @@ 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_pwrctrl_destroy:
> -	if (ret != -EPROBE_DEFER)
> +	if (ret != -EPROBE_DEFER && !pci->suspended)
>  		pci_pwrctrl_destroy_devices(dev);
>  err_reg_disable:
>  	if (imx_pcie->vpcie)
> @@ -1482,7 +1487,8 @@ 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);
>  }
> @@ -1990,12 +1996,16 @@ 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);
> -	pci_pwrctrl_destroy_devices(&pdev->dev);
> +	if (!pp->skip_pwrctrl_off)
> +		pci_pwrctrl_power_off_devices(&pdev->dev);
> +	if (!pci->suspended)
> +		pci_pwrctrl_destroy_devices(&pdev->dev);
>  }
>
>  static const struct imx_pcie_drvdata drvdata[] = {
> --
> 2.50.1
>
>