diff mbox series

[v2,1/3] dt-bindings: imx6q-pcie: add one regulator used to power up pcie phy

Message ID 1616564059-8713-2-git-send-email-hongxing.zhu@nxp.com
State New
Headers show
Series add one regulator used to power up pcie phy | expand

Commit Message

Richard Zhu March 24, 2021, 5:34 a.m. UTC
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>
---
 Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Lucas Stach March 24, 2021, 9:26 a.m. UTC | #1
Hi Richard,

Am Mittwoch, dem 24.03.2021 um 13:34 +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>
> ---
>  Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> index de4b2baf91e8..3248b7192ced 100644
> --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> @@ -38,6 +38,12 @@ 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 PCIe PHY power.
> +  On i.MX8MQ, 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.

This description of the internal driver behavior does not belong into a
DT binding description.
Instead the binding should describe the function of the regulator
exactly. From the datasheet I can see that there are actually 3
supplies (VPH, VP, VPTX) going into the PCIe PHY, so "regulator in
charge of PCIe PHY power" doesn't seem like a very accurate
description.

Regards,
Lucas
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
index de4b2baf91e8..3248b7192ced 100644
--- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
@@ -38,6 +38,12 @@  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 PCIe PHY power.
+  On i.MX8MQ, 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.
 
 Additional required properties for imx6sx-pcie:
 - clock names: Must include the following additional entries: