> -----Original Message-----
> From: Manivannan Sadhasivam <mani@xxxxxxxxxx>
> Sent: 2025年8月13日 1:12
> To: Hongxing Zhu <hongxing.zhu@xxxxxxx>
> Cc: Frank Li <frank.li@xxxxxxx>; l.stach@xxxxxxxxxxxxxx;
> lpieralisi@xxxxxxxxxx; kwilczynski@xxxxxxxxxx; robh@xxxxxxxxxx;
> bhelgaas@xxxxxxxxxx; shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2] PCI: imx6: Enable the vpcie regulator when fetch it
>
> On Thu, Jun 19, 2025 at 03:24:38PM GMT, Richard Zhu wrote:
> > Enable the vpcie regulator at probe time and keep it enabled for the
> > entire PCIe controller lifecycle. This ensures support for outbound
> > wake-up mechanism such as WAKE# signaling.
>
> I'm not sure about this part. For supporting WAKE#, Vaux supply has to be
> supplied to the endpoint. But here, 'vpcie' looks like the main 3.3V supply.
> So keeping it always on to support WAKE#, sounds to me that the
> component never enters the D3Cold state. So no WAKE# is required.
Hi Mani:
Thanks for your comments. You're right.
Another +3.3Vaux should be added to power up the WAKE# circuit.
Best Regards
Richard Zhu
>
> - Mani
>
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > ---
> > drivers/pci/controller/dwc/pci-imx6.c | 27
> > ++++-----------------------
> > 1 file changed, 4 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 5a38cfaf989b..7cab4bcfae56 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -159,7 +159,6 @@ struct imx_pcie {
> > u32 tx_deemph_gen2_6db;
> > u32 tx_swing_full;
> > u32 tx_swing_low;
> > - struct regulator *vpcie;
> > struct regulator *vph;
> > void __iomem *phy_base;
> >
> > @@ -1198,15 +1197,6 @@ static int imx_pcie_host_init(struct dw_pcie_rp
> *pp)
> > struct imx_pcie *imx_pcie = to_imx_pcie(pci);
> > int ret;
> >
> > - if (imx_pcie->vpcie) {
> > - ret = regulator_enable(imx_pcie->vpcie);
> > - if (ret) {
> > - dev_err(dev, "failed to enable vpcie regulator: %d\n",
> > - ret);
> > - return ret;
> > - }
> > - }
> > -
> > if (pp->bridge && imx_check_flag(imx_pcie, IMX_PCIE_FLAG_HAS_LUT)) {
> > pp->bridge->enable_device = imx_pcie_enable_device;
> > pp->bridge->disable_device = imx_pcie_disable_device; @@ -1222,7
> > +1212,7 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
> > ret = imx_pcie_clk_enable(imx_pcie);
> > if (ret) {
> > dev_err(dev, "unable to enable pcie clocks: %d\n", ret);
> > - goto err_reg_disable;
> > + return ret;
> > }
> >
> > if (imx_pcie->phy) {
> > @@ -1269,9 +1259,6 @@ static int imx_pcie_host_init(struct dw_pcie_rp
> *pp)
> > phy_exit(imx_pcie->phy);
> > err_clk_disable:
> > imx_pcie_clk_disable(imx_pcie);
> > -err_reg_disable:
> > - if (imx_pcie->vpcie)
> > - regulator_disable(imx_pcie->vpcie);
> > return ret;
> > }
> >
> > @@ -1286,9 +1273,6 @@ static void imx_pcie_host_exit(struct dw_pcie_rp
> *pp)
> > phy_exit(imx_pcie->phy);
> > }
> > imx_pcie_clk_disable(imx_pcie);
> > -
> > - if (imx_pcie->vpcie)
> > - regulator_disable(imx_pcie->vpcie);
> > }
> >
> > static void imx_pcie_host_post_init(struct dw_pcie_rp *pp) @@
> > -1739,12 +1723,9 @@ static int imx_pcie_probe(struct platform_device
> *pdev)
> > pci->max_link_speed = 1;
> > of_property_read_u32(node, "fsl,max-link-speed",
> > &pci->max_link_speed);
> >
> > - imx_pcie->vpcie = devm_regulator_get_optional(&pdev->dev, "vpcie");
> > - if (IS_ERR(imx_pcie->vpcie)) {
> > - if (PTR_ERR(imx_pcie->vpcie) != -ENODEV)
> > - return PTR_ERR(imx_pcie->vpcie);
> > - imx_pcie->vpcie = NULL;
> > - }
> > + ret = devm_regulator_get_enable_optional(&pdev->dev, "vpcie");
> > + if (ret < 0 && ret != -ENODEV)
> > + return dev_err_probe(dev, ret, "failed to enable vpcie");
> >
> > imx_pcie->vph = devm_regulator_get_optional(&pdev->dev, "vph");
> > if (IS_ERR(imx_pcie->vph)) {
> > --
> > 2.37.1
> >
>
> --
> மணிவண்ணன் சதாசிவம்
