[PATCH v4 0/2] PCI: imx6: Enable the vaux regulator when fetch it

[PATCH v4 0/2] PCI: imx6: Enable the vaux regulator when fetch it

[Richard Zhu]

Refer to PCIe CEM r6.0, sec 2.3 WAKE# Singal, WAKE# signal is only
asserted by the Add-in Card when all its functions are in D3Cold state
and at least one of its functions is enabled for wakeup generation. The
3.3V auxiliary power (+3.3Vaux) must be present and used for wakeup
process. Since the main power supply would be gated off to let Add-in
Card to be in D3Cold, get the vaux and keep it enabled to power up WAKE#
circuit for the entire PCIe controller lifecycle when it's present.

v4 changes:
Move the dt-binding to snps,dw-pcie-common.yaml.

v3 changes:
Add a new vaux power supply used to specify the regulator powered up the
WAKE# circuit on the connector when WAKE# is supported.

v2 changes:
Update the commit message, and add reviewed-by from Frank.
https://patchwork.kernel.org/project/linux-pci/patch/20250619072438.125921-1-hongxing.zhu@nxp.com/

[PATCH v4 1/2] dt-bindings: PCI: dwc: Add vaux regulator
[PATCH v4 2/2] PCI: imx6: Enable the vaux regulator when fetch it

Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml |  6 ++++++
drivers/pci/controller/dwc/pci-imx6.c                          | 15 +++++++++++++++
2 files changed, 21 insertions(+)

[PATCH v4 1/2] dt-bindings: PCI: dwc: Add vaux regulator

[Richard Zhu]

Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
asserted by the Add-in Card when all its functions are in D3Cold state
and at least one of its functions is enabled for wakeup generation.

The 3.3V auxiliary power (+3.3Vaux) must be present and used for wakeup
process. Since the main power supply would be gated off to let Add-in
Card to be in D3Cold, add the vaux and keep it enabled to power up WAKE#
circuit for the entire PCIe controller lifecycle when WAKE# is supported.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 .../devicetree/bindings/pci/snps,dw-pcie-common.yaml        | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml b/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
index 34594972d8dbe..5283f51388584 100644
--- a/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
+++ b/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
@@ -262,6 +262,12 @@ properties:
 
   dma-coherent: true
 
+  vaux-supply:
+    description: Should specify the regulator in charge of power source
+      of the WAKE# generation on the PCIe connector. When the WAKE# is
+      enabled, this regualor would be always on and used to power up
+      WAKE# circuit.
+
 additionalProperties: true
 
 ...
-- 
2.37.1

[PATCH v4 2/2] PCI: imx6: Enable the vaux regulator when fetch it

[Richard Zhu]

Enable the vaux 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.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 5a38cfaf989b1..1c1dce2d87e44 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -159,6 +159,7 @@ struct imx_pcie {
 	u32			tx_deemph_gen2_6db;
 	u32			tx_swing_full;
 	u32			tx_swing_low;
+	struct regulator	*vaux;
 	struct regulator	*vpcie;
 	struct regulator	*vph;
 	void __iomem		*phy_base;
@@ -1739,6 +1740,20 @@ 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);
 
+	/*
+	 * Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
+	 * asserted by the Add-in Card when all its functions are in D3Cold
+	 * state and at least one of its functions is enabled for wakeup
+	 * generation. The 3.3V auxiliary power (+3.3Vaux) must be present and
+	 * used for wakeup process. Since the main power supply would be gated
+	 * off to let Add-in Card to be in D3Cold, get the vaux and keep it
+	 * enabled to power up WAKE# circuit for the entire PCIe controller
+	 * lifecycle when WAKE# is supported.
+	 */
+	ret = devm_regulator_get_enable_optional(&pdev->dev, "vaux");
+	if (ret < 0 && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to enable vaux");
+
 	imx_pcie->vpcie = devm_regulator_get_optional(&pdev->dev, "vpcie");
 	if (IS_ERR(imx_pcie->vpcie)) {
 		if (PTR_ERR(imx_pcie->vpcie) != -ENODEV)
-- 
2.37.1

Re: [PATCH v4 1/2] dt-bindings: PCI: dwc: Add vaux regulator

[Rob Herring (Arm)]

On Tue, 19 Aug 2025 15:16:29 +0800, Richard Zhu wrote:
> Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
> asserted by the Add-in Card when all its functions are in D3Cold state
> and at least one of its functions is enabled for wakeup generation.
> 
> The 3.3V auxiliary power (+3.3Vaux) must be present and used for wakeup
> process. Since the main power supply would be gated off to let Add-in
> Card to be in D3Cold, add the vaux and keep it enabled to power up WAKE#
> circuit for the entire PCIe controller lifecycle when WAKE# is supported.
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> ---
>  .../devicetree/bindings/pci/snps,dw-pcie-common.yaml        | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:


doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20250819071630.1813134-2-hongxing.zhu@nxp.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

RE: [PATCH v4 2/2] PCI: imx6: Enable the vaux regulator when fetch it

[Sherry Sun]

> -----Original Message-----
> From: Richard Zhu <hongxing.zhu@nxp.com>
> Sent: Tuesday, August 19, 2025 3:17 PM
> To: Frank Li <frank.li@nxp.com>; l.stach@pengutronix.de;
> lpieralisi@kernel.org; kwilczynski@kernel.org; mani@kernel.org;
> robh@kernel.org; krzk+dt@kernel.org; conor+dt@kernel.org;
> bhelgaas@google.com; shawnguo@kernel.org; s.hauer@pengutronix.de;
> kernel@pengutronix.de; festevam@gmail.com
> Cc: linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> devicetree@vger.kernel.org; imx@lists.linux.dev; linux-
> kernel@vger.kernel.org; Hongxing Zhu <hongxing.zhu@nxp.com>
> Subject: [PATCH v4 2/2] PCI: imx6: Enable the vaux regulator when fetch it
> 
> Enable the vaux 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.
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> b/drivers/pci/controller/dwc/pci-imx6.c
> index 5a38cfaf989b1..1c1dce2d87e44 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -159,6 +159,7 @@ struct imx_pcie {
>  	u32			tx_deemph_gen2_6db;
>  	u32			tx_swing_full;
>  	u32			tx_swing_low;
> +	struct regulator	*vaux;

Hi Richard, this seems defined but not used?

Best Regards
Sherry

>  	struct regulator	*vpcie;
>  	struct regulator	*vph;
>  	void __iomem		*phy_base;
> @@ -1739,6 +1740,20 @@ 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);
> 
> +	/*
> +	 * Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
> +	 * asserted by the Add-in Card when all its functions are in D3Cold
> +	 * state and at least one of its functions is enabled for wakeup
> +	 * generation. The 3.3V auxiliary power (+3.3Vaux) must be present
> and
> +	 * used for wakeup process. Since the main power supply would be
> gated
> +	 * off to let Add-in Card to be in D3Cold, get the vaux and keep it
> +	 * enabled to power up WAKE# circuit for the entire PCIe controller
> +	 * lifecycle when WAKE# is supported.
> +	 */
> +	ret = devm_regulator_get_enable_optional(&pdev->dev, "vaux");
> +	if (ret < 0 && ret != -ENODEV)
> +		return dev_err_probe(dev, ret, "failed to enable vaux");
> +
>  	imx_pcie->vpcie = devm_regulator_get_optional(&pdev->dev,
> "vpcie");
>  	if (IS_ERR(imx_pcie->vpcie)) {
>  		if (PTR_ERR(imx_pcie->vpcie) != -ENODEV)
> --
> 2.37.1
> 

Re: [PATCH v4 1/2] dt-bindings: PCI: dwc: Add vaux regulator

[Manivannan Sadhasivam]

On Tue, Aug 19, 2025 at 03:16:29PM GMT, Richard Zhu wrote:
> Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
> asserted by the Add-in Card when all its functions are in D3Cold state
> and at least one of its functions is enabled for wakeup generation.
> 
> The 3.3V auxiliary power (+3.3Vaux) must be present and used for wakeup
> process. Since the main power supply would be gated off to let Add-in
> Card to be in D3Cold, add the vaux and keep it enabled to power up WAKE#
> circuit for the entire PCIe controller lifecycle when WAKE# is supported.
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> ---
>  .../devicetree/bindings/pci/snps,dw-pcie-common.yaml        | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml b/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
> index 34594972d8dbe..5283f51388584 100644
> --- a/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
> +++ b/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
> @@ -262,6 +262,12 @@ properties:
>  
>    dma-coherent: true
>  
> +  vaux-supply:
> +    description: Should specify the regulator in charge of power source
> +      of the WAKE# generation on the PCIe connector. When the WAKE# is
> +      enabled, this regualor would be always on and used to power up
> +      WAKE# circuit.

3.3Vaux supply is already documented in the dtschema:
https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/pci/pci-bus-common.yaml#L179

So you should use that instead.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v4 2/2] PCI: imx6: Enable the vaux regulator when fetch it

[Manivannan Sadhasivam]

On Tue, Aug 19, 2025 at 03:16:30PM GMT, Richard Zhu wrote:
> Enable the vaux 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.
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 5a38cfaf989b1..1c1dce2d87e44 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -159,6 +159,7 @@ struct imx_pcie {
>  	u32			tx_deemph_gen2_6db;
>  	u32			tx_swing_full;
>  	u32			tx_swing_low;
> +	struct regulator	*vaux;
>  	struct regulator	*vpcie;
>  	struct regulator	*vph;
>  	void __iomem		*phy_base;
> @@ -1739,6 +1740,20 @@ 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);
>  
> +	/*
> +	 * Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
> +	 * asserted by the Add-in Card when all its functions are in D3Cold
> +	 * state and at least one of its functions is enabled for wakeup
> +	 * generation. The 3.3V auxiliary power (+3.3Vaux) must be present and
> +	 * used for wakeup process. Since the main power supply would be gated
> +	 * off to let Add-in Card to be in D3Cold, get the vaux and keep it
> +	 * enabled to power up WAKE# circuit for the entire PCIe controller
> +	 * lifecycle when WAKE# is supported.
> +	 */

This comment implies that the presence of Vaux is dependent on WAKE#. But there
is no such check present in the code. Maybe you are referring to the fact that
the platform will only supply Vaux if it intends to support WAKE#?

But I guess you can just drop the comment altogether and move it to patch
description.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

RE: [PATCH v4 1/2] dt-bindings: PCI: dwc: Add vaux regulator

[Hongxing Zhu]

> -----Original Message-----
> From: Manivannan Sadhasivam <mani@kernel.org>
> Sent: 2025年8月19日 16:46
> To: Hongxing Zhu <hongxing.zhu@nxp.com>
> Cc: Frank Li <frank.li@nxp.com>; l.stach@pengutronix.de;
> lpieralisi@kernel.org; kwilczynski@kernel.org; robh@kernel.org;
> krzk+dt@kernel.org; conor+dt@kernel.org; bhelgaas@google.com;
> shawnguo@kernel.org; s.hauer@pengutronix.de; kernel@pengutronix.de;
> festevam@gmail.com; linux-pci@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org;
> imx@lists.linux.dev; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v4 1/2] dt-bindings: PCI: dwc: Add vaux regulator
> 
> On Tue, Aug 19, 2025 at 03:16:29PM GMT, Richard Zhu wrote:
> > Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
> > asserted by the Add-in Card when all its functions are in D3Cold state
> > and at least one of its functions is enabled for wakeup generation.
> >
> > The 3.3V auxiliary power (+3.3Vaux) must be present and used for
> > wakeup process. Since the main power supply would be gated off to let
> > Add-in Card to be in D3Cold, add the vaux and keep it enabled to power
> > up WAKE# circuit for the entire PCIe controller lifecycle when WAKE# is
> supported.
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > ---
> >  .../devicetree/bindings/pci/snps,dw-pcie-common.yaml        | 6
> ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git
> > a/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
> > b/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
> > index 34594972d8dbe..5283f51388584 100644
> > --- a/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
> > +++ b/Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml
> > @@ -262,6 +262,12 @@ properties:
> >
> >    dma-coherent: true
> >
> > +  vaux-supply:
> > +    description: Should specify the regulator in charge of power source
> > +      of the WAKE# generation on the PCIe connector. When the WAKE#
> is
> > +      enabled, this regualor would be always on and used to power up
> > +      WAKE# circuit.
> 
> 3.3Vaux supply is already documented in the dtschema:
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.
> com%2Fdevicetree-org%2Fdt-schema%2Fblob%2Fmain%2Fdtschema%2Fsche
> mas%2Fpci%2Fpci-bus-common.yaml%23L179&data=05%7C02%7Chongxing.z
> hu%40nxp.com%7C010fb118c1384dfa2b1a08dddefcd0ff%7C686ea1d3bc2b4c
> 6fa92cd99c5c301635%7C0%7C0%7C638911899600090830%7CUnknown%7CT
> WFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXa
> W4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=%2Bh
> CgrwfHFGY2D5%2B8dS4XRl4hoQWG0JpUmG5BZhRyW%2B8%3D&reserved=0
> 
> So you should use that instead.
Okay, got that, thanks.

Best Regards
Richard Zhu
> 
> - Mani
> 
> --
> மணிவண்ணன் சதாசிவம்

RE: [PATCH v4 2/2] PCI: imx6: Enable the vaux regulator when fetch it

[Hongxing Zhu]

> -----Original Message-----
> From: Manivannan Sadhasivam <mani@kernel.org>
> Sent: 2025年8月19日 16:52
> To: Hongxing Zhu <hongxing.zhu@nxp.com>
> Cc: Frank Li <frank.li@nxp.com>; l.stach@pengutronix.de;
> lpieralisi@kernel.org; kwilczynski@kernel.org; robh@kernel.org;
> krzk+dt@kernel.org; conor+dt@kernel.org; bhelgaas@google.com;
> shawnguo@kernel.org; s.hauer@pengutronix.de; kernel@pengutronix.de;
> festevam@gmail.com; linux-pci@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org;
> imx@lists.linux.dev; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v4 2/2] PCI: imx6: Enable the vaux regulator when fetch
> it
> 
> On Tue, Aug 19, 2025 at 03:16:30PM GMT, Richard Zhu wrote:
> > Enable the vaux 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.
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 15 +++++++++++++++
> >  1 file changed, 15 insertions(+)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 5a38cfaf989b1..1c1dce2d87e44 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -159,6 +159,7 @@ struct imx_pcie {
> >  	u32			tx_deemph_gen2_6db;
> >  	u32			tx_swing_full;
> >  	u32			tx_swing_low;
> > +	struct regulator	*vaux;
> >  	struct regulator	*vpcie;
> >  	struct regulator	*vph;
> >  	void __iomem		*phy_base;
> > @@ -1739,6 +1740,20 @@ 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);
> >
> > +	/*
> > +	 * Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
> > +	 * asserted by the Add-in Card when all its functions are in D3Cold
> > +	 * state and at least one of its functions is enabled for wakeup
> > +	 * generation. The 3.3V auxiliary power (+3.3Vaux) must be present and
> > +	 * used for wakeup process. Since the main power supply would be
> gated
> > +	 * off to let Add-in Card to be in D3Cold, get the vaux and keep it
> > +	 * enabled to power up WAKE# circuit for the entire PCIe controller
> > +	 * lifecycle when WAKE# is supported.
> > +	 */
> 
> This comment implies that the presence of Vaux is dependent on WAKE#.
> But there is no such check present in the code. Maybe you are referring to
> the fact that the platform will only supply Vaux if it intends to support
> WAKE#?
Yes, it is. The Vaux power supply would be present if the WAKE# is supported
 by the board.
> 
> But I guess you can just drop the comment altogether and move it to patch
> description.
Okay.

Best Regards
Richard Zhu
> 
> - Mani
> 
> --
> மணிவண்ணன் சதாசிவம்