[RESEND v4 0/2] add one regulator used to power up pcie phy

[RESEND v4 0/2] add one regulator used to power up pcie phy

[Richard Zhu]

Changes:
Only add "Reviewed-by: Lucas Stach <l.stach@pengutronix.de>" in the
first patch. No other changes. Make it easier to be integrated later.

[RESEND v4 1/2] dt-bindings: imx6q-pcie: add one regulator used to
[RESEND v4 2/2] PCI: imx: clear vreg bypass when pcie vph voltage is

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[RESEND v4 1/2] dt-bindings: imx6q-pcie: add one regulator used to power up pcie phy

[Richard Zhu]

Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
In default, the PCIE_VPH voltage is suggested to be 1.8v refer to data
sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic design,
the VREG_BYPASS bits of GPR registers should be cleared from default
value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator would be
turned on.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
---
 Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
index de4b2baf91e8..d8971ab99274 100644
--- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
@@ -38,6 +38,9 @@ Optional properties:
   The regulator will be enabled when initializing the PCIe host and
   disabled either as part of the init process or when shutting down the
   host.
+- vph-supply: Should specify the regulator in charge of VPH one of the three
+  PCIe PHY powers. This regulator can be supplied by both 1.8v and 3.3v voltage
+  supplies.
 
 Additional required properties for imx6sx-pcie:
 - clock names: Must include the following additional entries:
-- 
2.17.1


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Re: [RESEND v4 1/2] dt-bindings: imx6q-pcie: add one regulator used to power up pcie phy

[Lucas Stach]

Hi Lorenzo,

have those two patches fallen through some crack? AFAICS they are gone
from patchwork, but I also can't find them in any branch in the usual
git repos.

Regards,
Lucas

Am Dienstag, dem 30.03.2021 um 16:08 +0800 schrieb Richard Zhu:
> Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
> In default, the PCIE_VPH voltage is suggested to be 1.8v refer to data
> sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic design,
> the VREG_BYPASS bits of GPR registers should be cleared from default
> value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator would be
> turned on.
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> ---
>  Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> index de4b2baf91e8..d8971ab99274 100644
> --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> @@ -38,6 +38,9 @@ Optional properties:
>    The regulator will be enabled when initializing the PCIe host and
>    disabled either as part of the init process or when shutting down the
>    host.
> +- vph-supply: Should specify the regulator in charge of VPH one of the three
> +  PCIe PHY powers. This regulator can be supplied by both 1.8v and 3.3v voltage
> +  supplies.
>  
> 
>  Additional required properties for imx6sx-pcie:
>  - clock names: Must include the following additional entries:



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Re: [RESEND v4 1/2] dt-bindings: imx6q-pcie: add one regulator used to power up pcie phy

[Bjorn Helgaas]

On Thu, May 06, 2021 at 06:08:24PM +0200, Lucas Stach wrote:
> Hi Lorenzo,
> 
> have those two patches fallen through some crack? AFAICS they are gone
> from patchwork, but I also can't find them in any branch in the usual
> git repos.

They were marked "accepted" in patchwork but must have fallen through
the cracks.  I reset them to "new" and assigned to Lorenzo.

Neither one follows the subject line capitalization conventions.

The subject line of this patch (1/2) doesn't really make sense.  I
*think* this adds a property ("vph-supply") to indicate which
regulator supplys power to the PHY.

> Am Dienstag, dem 30.03.2021 um 16:08 +0800 schrieb Richard Zhu:
> > Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
> > In default, the PCIE_VPH voltage is suggested to be 1.8v refer to data
> > sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic design,
> > the VREG_BYPASS bits of GPR registers should be cleared from default
> > value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator would be
> > turned on.

This commit log doesn't describe the patch, either.  Maybe something
like this:

  dt-bindings: imx6q-pcie: Add "vph-supply" for PHY supply voltage

  The i.MX8MQ PCIe PHY can use either a 1.8V or a 3.3V power supply.
  Add a "vph-supply" property to indicate which regulator supplies
  power for the PHY.

> > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> > ---
> >  Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > index de4b2baf91e8..d8971ab99274 100644
> > --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > @@ -38,6 +38,9 @@ Optional properties:
> >    The regulator will be enabled when initializing the PCIe host and
> >    disabled either as part of the init process or when shutting down the
> >    host.
> > +- vph-supply: Should specify the regulator in charge of VPH one of the three
> > +  PCIe PHY powers. This regulator can be supplied by both 1.8v and 3.3v voltage
> > +  supplies.

Just going by examples for other drivers, I think this should say
something like this:

  - vph-supply: Regulator for i.MX8MQ PCIe PHY.  May supply either
    1.8V or 3.3V.

You mentioned "one of the three PCIe PHY powers"; I don't know what
that means, so I don't know whether it's important to include.

I also don't know what "vph" means; if the "ph" is part of "phy", it'd
be nicer to include the "y", so it would be "vphy-supply".

> >  Additional required properties for imx6sx-pcie:
> >  - clock names: Must include the following additional entries:

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RE: [EXT] Re: [RESEND v4 1/2] dt-bindings: imx6q-pcie: add one regulator used to power up pcie phy

[Richard Zhu]

Hi Bjorn:
It seems that the email I replied on May07, is missing.
Re-send it again.

Best Regards
Richard Zhu

> -----Original Message-----
> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: Friday, May 7, 2021 5:01 AM
> To: Lucas Stach <l.stach@pengutronix.de>
> Cc: lorenzo.pieralisi@arm.com; linux-pci@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; kernel@pengutronix.de; Richard Zhu
> <hongxing.zhu@nxp.com>; andrew.smirnov@gmail.com;
> shawnguo@kernel.org; kw@linux.com; bhelgaas@google.com;
> stefan@agner.ch
> Subject: [EXT] Re: [RESEND v4 1/2] dt-bindings: imx6q-pcie: add one
> regulator used to power up pcie phy
> On Thu, May 06, 2021 at 06:08:24PM +0200, Lucas Stach wrote:
> > Hi Lorenzo,
> >
> > have those two patches fallen through some crack? AFAICS they are gone
> > from patchwork, but I also can't find them in any branch in the usual
> > git repos.
> 
> They were marked "accepted" in patchwork but must have fallen through the
> cracks.  I reset them to "new" and assigned to Lorenzo.
> 
> Neither one follows the subject line capitalization conventions.
> 
> The subject line of this patch (1/2) doesn't really make sense.  I
> *think* this adds a property ("vph-supply") to indicate which regulator supplys
> power to the PHY.
> 
> > Am Dienstag, dem 30.03.2021 um 16:08 +0800 schrieb Richard Zhu:
> > > Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
> > > In default, the PCIE_VPH voltage is suggested to be 1.8v refer to
> > > data sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic
> > > design, the VREG_BYPASS bits of GPR registers should be cleared from
> > > default value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator
> > > would be turned on.
> 
> This commit log doesn't describe the patch, either.  Maybe something like
> this:
> 
>   dt-bindings: imx6q-pcie: Add "vph-supply" for PHY supply voltage
> 
>   The i.MX8MQ PCIe PHY can use either a 1.8V or a 3.3V power supply.
>   Add a "vph-supply" property to indicate which regulator supplies
>   power for the PHY.
> 
[Richard Zhu] I'm fine with this one.

> > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> > > ---
> > >  Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git
> > > a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > > b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > > index de4b2baf91e8..d8971ab99274 100644
> > > --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > > +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > > @@ -38,6 +38,9 @@ Optional properties:
> > >    The regulator will be enabled when initializing the PCIe host and
> > >    disabled either as part of the init process or when shutting down the
> > >    host.
> > > +- vph-supply: Should specify the regulator in charge of VPH one of
> > > +the three
> > > +  PCIe PHY powers. This regulator can be supplied by both 1.8v and
> > > +3.3v voltage
> > > +  supplies.
> 
> Just going by examples for other drivers, I think this should say something like
> this:
> 
>   - vph-supply: Regulator for i.MX8MQ PCIe PHY.  May supply either
>     1.8V or 3.3V.
> 
> You mentioned "one of the three PCIe PHY powers"; I don't know what that
> means, so I don't know whether it's important to include.
> 
> I also don't know what "vph" means; if the "ph" is part of "phy", it'd be nicer
> to include the "y", so it would be "vphy-supply".
> 
[Richard Zhu] There are three power supplies in total required by the PHY.
- vp: PHY analog and digital supply
- vptxN: PHY transmit supply
-vph: High-voltage power supply.
Only vph is handled by SW here.

BR
Richard
> > >  Additional required properties for imx6sx-pcie:
> > >  - clock names: Must include the following additional entries:

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[RESEND v4 2/2] PCI: imx: clear vreg bypass when pcie vph voltage is 3v3

[Richard Zhu]

Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
In default, the PCIE_VPH voltage is suggested to be 1.8v refer to data
sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic design,
the VREG_BYPASS bits of GPR registers should be cleared from default
value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator would be
turned on.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/pci/controller/dwc/pci-imx6.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 853ea8e82952..94b43b4ecca1 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -37,6 +37,7 @@
 #define IMX8MQ_GPR_PCIE_REF_USE_PAD		BIT(9)
 #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN	BIT(10)
 #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE	BIT(11)
+#define IMX8MQ_GPR_PCIE_VREG_BYPASS		BIT(12)
 #define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE	GENMASK(11, 8)
 #define IMX8MQ_PCIE2_BASE_ADDR			0x33c00000
 
@@ -80,6 +81,7 @@ struct imx6_pcie {
 	u32			tx_swing_full;
 	u32			tx_swing_low;
 	struct regulator	*vpcie;
+	struct regulator	*vph;
 	void __iomem		*phy_base;
 
 	/* power domain for pcie */
@@ -621,6 +623,17 @@ static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
 				   imx6_pcie_grp_offset(imx6_pcie),
 				   IMX8MQ_GPR_PCIE_REF_USE_PAD,
 				   IMX8MQ_GPR_PCIE_REF_USE_PAD);
+		/*
+		 * Regarding the datasheet, the PCIE_VPH is suggested
+		 * to be 1.8V. If the PCIE_VPH is supplied by 3.3V, the
+		 * VREG_BYPASS should be cleared to zero.
+		 */
+		if (imx6_pcie->vph &&
+		    regulator_get_voltage(imx6_pcie->vph) > 3000000)
+			regmap_update_bits(imx6_pcie->iomuxc_gpr,
+					   imx6_pcie_grp_offset(imx6_pcie),
+					   IMX8MQ_GPR_PCIE_VREG_BYPASS,
+					   0);
 		break;
 	case IMX7D:
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
@@ -1130,6 +1143,13 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 		imx6_pcie->vpcie = NULL;
 	}
 
+	imx6_pcie->vph = devm_regulator_get_optional(&pdev->dev, "vph");
+	if (IS_ERR(imx6_pcie->vph)) {
+		if (PTR_ERR(imx6_pcie->vph) != -ENODEV)
+			return PTR_ERR(imx6_pcie->vph);
+		imx6_pcie->vph = NULL;
+	}
+
 	platform_set_drvdata(pdev, imx6_pcie);
 
 	ret = imx6_pcie_attach_pd(dev);
-- 
2.17.1


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Re: [RESEND v4 2/2] PCI: imx: clear vreg bypass when pcie vph voltage is 3v3

[Bjorn Helgaas]

On Tue, Mar 30, 2021 at 04:08:21PM +0800, Richard Zhu wrote:
> Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
> In default, the PCIE_VPH voltage is suggested to be 1.8v refer to data
> sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic design,
> the VREG_BYPASS bits of GPR registers should be cleared from default
> value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator would be
> turned on.

Maybe something like this?

  PCI: imx6: Enable PHY internal regulator when supplied >3V

  The i.MX8MQ PCIe PHY needs 1.8V but can by supplied by either a 1.8V
  or a 3.3V regulator.  

  The "vph-supply" DT property tells us which external regulator
  supplies the PHY.  If that regulator supplies anything over 3V,
  enable the PHY's internal 3.3V-to-1.8V regulator.

> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 853ea8e82952..94b43b4ecca1 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -37,6 +37,7 @@
>  #define IMX8MQ_GPR_PCIE_REF_USE_PAD		BIT(9)
>  #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN	BIT(10)
>  #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE	BIT(11)
> +#define IMX8MQ_GPR_PCIE_VREG_BYPASS		BIT(12)
>  #define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE	GENMASK(11, 8)
>  #define IMX8MQ_PCIE2_BASE_ADDR			0x33c00000
>  
> @@ -80,6 +81,7 @@ struct imx6_pcie {
>  	u32			tx_swing_full;
>  	u32			tx_swing_low;
>  	struct regulator	*vpcie;
> +	struct regulator	*vph;
>  	void __iomem		*phy_base;
>  
>  	/* power domain for pcie */
> @@ -621,6 +623,17 @@ static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
>  				   imx6_pcie_grp_offset(imx6_pcie),
>  				   IMX8MQ_GPR_PCIE_REF_USE_PAD,
>  				   IMX8MQ_GPR_PCIE_REF_USE_PAD);
> +		/*
> +		 * Regarding the datasheet, the PCIE_VPH is suggested
> +		 * to be 1.8V. If the PCIE_VPH is supplied by 3.3V, the
> +		 * VREG_BYPASS should be cleared to zero.
> +		 */
> +		if (imx6_pcie->vph &&
> +		    regulator_get_voltage(imx6_pcie->vph) > 3000000)
> +			regmap_update_bits(imx6_pcie->iomuxc_gpr,
> +					   imx6_pcie_grp_offset(imx6_pcie),
> +					   IMX8MQ_GPR_PCIE_VREG_BYPASS,
> +					   0);
>  		break;
>  	case IMX7D:
>  		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> @@ -1130,6 +1143,13 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  		imx6_pcie->vpcie = NULL;
>  	}
>  
> +	imx6_pcie->vph = devm_regulator_get_optional(&pdev->dev, "vph");
> +	if (IS_ERR(imx6_pcie->vph)) {
> +		if (PTR_ERR(imx6_pcie->vph) != -ENODEV)
> +			return PTR_ERR(imx6_pcie->vph);
> +		imx6_pcie->vph = NULL;
> +	}
> +
>  	platform_set_drvdata(pdev, imx6_pcie);
>  
>  	ret = imx6_pcie_attach_pd(dev);
> -- 
> 2.17.1
> 

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RE: [EXT] Re: [RESEND v4 2/2] PCI: imx: clear vreg bypass when pcie vph voltage is 3v3

[Richard Zhu]

Hi Bjorn:
It seems that the email I replied on May07, is missing.
Re-send it.

Best Regards
Richard Zhu
> -----Original Message-----
> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: Friday, May 7, 2021 5:09 AM
> To: Richard Zhu <hongxing.zhu@nxp.com>
> Cc: l.stach@pengutronix.de; andrew.smirnov@gmail.com;
> shawnguo@kernel.org; kw@linux.com; bhelgaas@google.com;
> stefan@agner.ch; lorenzo.pieralisi@arm.com; linux-pci@vger.kernel.org;
> dl-linux-imx <linux-imx@nxp.com>; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; kernel@pengutronix.de
> Subject: [EXT] Re: [RESEND v4 2/2] PCI: imx: clear vreg bypass when pcie vph
> voltage is 3v3
> 
> Caution: EXT Email
> 
> On Tue, Mar 30, 2021 at 04:08:21PM +0800, Richard Zhu wrote:
> > Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
> > In default, the PCIE_VPH voltage is suggested to be 1.8v refer to data
> > sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic design,
> > the VREG_BYPASS bits of GPR registers should be cleared from default
> > value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator would be
> > turned on.
> 
> Maybe something like this?
> 
>   PCI: imx6: Enable PHY internal regulator when supplied >3V
> 
>   The i.MX8MQ PCIe PHY needs 1.8V but can by supplied by either a 1.8V
>   or a 3.3V regulator.
> 
>   The "vph-supply" DT property tells us which external regulator
>   supplies the PHY.  If that regulator supplies anything over 3V,
>   enable the PHY's internal 3.3V-to-1.8V regulator.
> 
[Richard Zhu] Hi Bjorn:
Thanks for your comments.
vph is the "high-voltage power supply" of the PHY.
How do you think with the following one with some minor updates?

   PCI: imx6: Enable PHY internal regulator when supplied >3V

   The i.MX8MQ PCIe PHY needs 1.8V in default but can be supplied by
   either a 1.8V or a 3.3V regulator.

   The "vph-supply" DT property tells us which external regulator
   supplies the PHY. If that regulator supplies anything over 3V,
   enable the PHY's internal 3.3V-to-1.8V regulator.
BR
Richard
> > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 20 ++++++++++++++++++++
> >  1 file changed, 20 insertions(+)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 853ea8e82952..94b43b4ecca1 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -37,6 +37,7 @@
> >  #define IMX8MQ_GPR_PCIE_REF_USE_PAD          BIT(9)
> >  #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN  BIT(10)
> >  #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE     BIT(11)
> > +#define IMX8MQ_GPR_PCIE_VREG_BYPASS          BIT(12)
> >  #define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE  GENMASK(11, 8)
> >  #define IMX8MQ_PCIE2_BASE_ADDR
> 0x33c00000
> >
> > @@ -80,6 +81,7 @@ struct imx6_pcie {
> >       u32                     tx_swing_full;
> >       u32                     tx_swing_low;
> >       struct regulator        *vpcie;
> > +     struct regulator        *vph;
> >       void __iomem            *phy_base;
> >
> >       /* power domain for pcie */
> > @@ -621,6 +623,17 @@ static void imx6_pcie_init_phy(struct imx6_pcie
> *imx6_pcie)
> >                                  imx6_pcie_grp_offset(imx6_pcie),
> >
> IMX8MQ_GPR_PCIE_REF_USE_PAD,
> >
> IMX8MQ_GPR_PCIE_REF_USE_PAD);
> > +             /*
> > +              * Regarding the datasheet, the PCIE_VPH is suggested
> > +              * to be 1.8V. If the PCIE_VPH is supplied by 3.3V, the
> > +              * VREG_BYPASS should be cleared to zero.
> > +              */
> > +             if (imx6_pcie->vph &&
> > +                 regulator_get_voltage(imx6_pcie->vph) > 3000000)
> > +                     regmap_update_bits(imx6_pcie->iomuxc_gpr,
> > +
> imx6_pcie_grp_offset(imx6_pcie),
> > +
> IMX8MQ_GPR_PCIE_VREG_BYPASS,
> > +                                        0);
> >               break;
> >       case IMX7D:
> >               regmap_update_bits(imx6_pcie->iomuxc_gpr,
> IOMUXC_GPR12,
> > @@ -1130,6 +1143,13 @@ static int imx6_pcie_probe(struct
> platform_device *pdev)
> >               imx6_pcie->vpcie = NULL;
> >       }
> >
> > +     imx6_pcie->vph = devm_regulator_get_optional(&pdev->dev,
> "vph");
> > +     if (IS_ERR(imx6_pcie->vph)) {
> > +             if (PTR_ERR(imx6_pcie->vph) != -ENODEV)
> > +                     return PTR_ERR(imx6_pcie->vph);
> > +             imx6_pcie->vph = NULL;
> > +     }
> > +
> >       platform_set_drvdata(pdev, imx6_pcie);
> >
> >       ret = imx6_pcie_attach_pd(dev);
> > --
> > 2.17.1
> >

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