diff mbox series

[V1,1/4] dt-bindings: Add "hotplug-gpios" PCIe property

Message ID 20220930192747.21471-2-vidyas@nvidia.com (mailing list archive)
State New
Delegated to: Bjorn Helgaas
Headers show
Series GPIO based PCIe Hot-Plug support | expand

Commit Message

Vidya Sagar Sept. 30, 2022, 7:27 p.m. UTC
Provide a way for the firmware to tell the OS about the GPIO that can be
used to get the Hot-Plug and Unplug events.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
---
 Documentation/devicetree/bindings/pci/pci.txt | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Lukas Wunner Oct. 1, 2022, 3:56 p.m. UTC | #1
On Sat, Oct 01, 2022 at 12:57:44AM +0530, Vidya Sagar wrote:
> Provide a way for the firmware to tell the OS about the GPIO that can be
> used to get the Hot-Plug and Unplug events.
[...]
> --- a/Documentation/devicetree/bindings/pci/pci.txt
> +++ b/Documentation/devicetree/bindings/pci/pci.txt
> @@ -32,6 +32,10 @@ driver implementation may support the following properties:
>     root port to downstream device and host bridge drivers can do programming
>     which depends on CLKREQ signal existence. For example, programming root port
>     not to advertise ASPM L1 Sub-States support if there is no CLKREQ signal.
> +- hotplug-gpios:
> +   If present this property specifies the GPIO to be used for Hot-Plug/Unplug
> +   functionality. It is used by the PCIe GPIO Hot-Plug core driver for
> +   PCIe device Hot-Plug/Unplug events.

Please specify the GPIO's semantics in more detail:
Is the pin high as long as presence of a card is detected?
Or does it pulse when a hotplug/unplug event occurs?

Thanks,

Lukas
Pali Rohár Oct. 1, 2022, 4:10 p.m. UTC | #2
On Saturday 01 October 2022 17:56:26 Lukas Wunner wrote:
> On Sat, Oct 01, 2022 at 12:57:44AM +0530, Vidya Sagar wrote:
> > Provide a way for the firmware to tell the OS about the GPIO that can be
> > used to get the Hot-Plug and Unplug events.
> [...]
> > --- a/Documentation/devicetree/bindings/pci/pci.txt
> > +++ b/Documentation/devicetree/bindings/pci/pci.txt
> > @@ -32,6 +32,10 @@ driver implementation may support the following properties:
> >     root port to downstream device and host bridge drivers can do programming
> >     which depends on CLKREQ signal existence. For example, programming root port
> >     not to advertise ASPM L1 Sub-States support if there is no CLKREQ signal.
> > +- hotplug-gpios:
> > +   If present this property specifies the GPIO to be used for Hot-Plug/Unplug
> > +   functionality. It is used by the PCIe GPIO Hot-Plug core driver for
> > +   PCIe device Hot-Plug/Unplug events.
> 
> Please specify the GPIO's semantics in more detail:
> Is the pin high as long as presence of a card is detected?

Hello! In PCIe is this semantics called "Presence Detect" (see PCIe Slot
Capabilities). So should it be rather named "presence-detect-gpios"
instead of hotplug?

> Or does it pulse when a hotplug/unplug event occurs?
> 
> Thanks,
> 
> Lukas
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt
index 6a8f2874a24d..7b89bddc8dde 100644
--- a/Documentation/devicetree/bindings/pci/pci.txt
+++ b/Documentation/devicetree/bindings/pci/pci.txt
@@ -32,6 +32,10 @@  driver implementation may support the following properties:
    root port to downstream device and host bridge drivers can do programming
    which depends on CLKREQ signal existence. For example, programming root port
    not to advertise ASPM L1 Sub-States support if there is no CLKREQ signal.
+- hotplug-gpios:
+   If present this property specifies the GPIO to be used for Hot-Plug/Unplug
+   functionality. It is used by the PCIe GPIO Hot-Plug core driver for
+   PCIe device Hot-Plug/Unplug events.
 
 PCI-PCI Bridge properties
 -------------------------