[PATCH V2 1/8] PCI: imx6: Add skip_pwrctrl_off flag support

[Sherry Sun]

> Subject: Re: [PATCH V2 1/8] PCI: imx6: Add skip_pwrctrl_off flag support
> 
> On Tue, Jun 23, 2026 at 11:07:28AM +0800, Sherry Sun (OSS) wrote:
> > From: Sherry Sun <sherry.sun at 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.
> > 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 at 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);
> 
> Is possible move pci_pwrctrl_create_devices() of pci_pwrctrl_create_devices
> 
> and call it direct at probe() function, like other regulator_get function.
> 

Hi Frank,
That makes sense. However, if we move pci_pwrctrl_create_devices () to
probe(), we may need to add the following goto err_pwrctrl_destroy path
in imx_pcie_probe() to properly handle errors from
pci_pwrctrl_power_on_devices(), is that acceptable?

@@ -1960,11 +1949,15 @@ static int imx_pcie_probe(struct platform_device *pdev)
        if (ret)
                return ret;

+       ret = pci_pwrctrl_create_devices(dev);
+       if (ret)
+               return dev_err_probe(dev, ret, "failed to create pwrctrl devices\n");
+
        pci->use_parent_dt_ranges = true;
        if (imx_pcie->drvdata->mode == DW_PCIE_EP_TYPE) {
                ret = imx_add_pcie_ep(imx_pcie, pdev);
                if (ret < 0)
-                       return ret;
+                       goto err_pwrctrl_destroy;

                /*
                 * FIXME: Only single Device (EPF) is supported due to the
@@ -1979,7 +1972,7 @@ static int imx_pcie_probe(struct platform_device *pdev)
                pci->pp.use_atu_msg = true;
                ret = dw_pcie_host_init(&pci->pp);
                if (ret < 0)
-                       return ret;
+                       goto err_pwrctrl_destroy;

                if (pci_msi_enabled()) {
                        u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
@@ -1991,6 +1984,11 @@ static int imx_pcie_probe(struct platform_device *pdev)
        }

        return 0;
+
+err_pwrctrl_destroy:
+       if (ret != -EPROBE_DEFER)
+               pci_pwrctrl_destroy_devices(dev);
+       return ret;
 }

Best Regards
Sherry

> 
> > +		if (ret) {
> > +			dev_err(dev, "failed to create pwrctrl devices\n");
> > +			goto err_reg_disable;
> > +		}
> >  	}
> >
> > -	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
> >
> >