From: "Pali Rohár" <pali@kernel.org>
To: Lukas Wunner <lukas@wunner.de>
Cc: "Vidya Sagar" <vidyas@nvidia.com>,
bhelgaas@google.com, robh+dt@kernel.org,
krzysztof.kozlowski+dt@linaro.org, lpieralisi@kernel.org,
kw@linux.com, thierry.reding@gmail.com, jonathanh@nvidia.com,
mani@kernel.org, Sergey.Semin@baikalelectronics.ru,
jszhang@kernel.org, linux-pci@vger.kernel.org,
linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, kthota@nvidia.com,
mmaddireddy@nvidia.com, sagar.tv@gmail.com,
"Marek Behún" <kabel@kernel.org>,
"Jonathan Derrick" <jonathan.derrick@linux.dev>
Subject: Re: [PATCH V1 1/4] dt-bindings: Add "hotplug-gpios" PCIe property
Date: Sat, 1 Oct 2022 18:10:59 +0200 [thread overview]
Message-ID: <20221001161059.5ymdptqzslh3d55x@pali> (raw)
In-Reply-To: <20221001155626.GA9324@wunner.de>
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
next prev parent reply other threads:[~2022-10-01 16:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-30 19:27 [PATCH V1 0/4] GPIO based PCIe Hot-Plug support Vidya Sagar
2022-09-30 19:27 ` [PATCH V1 1/4] dt-bindings: Add "hotplug-gpios" PCIe property Vidya Sagar
2022-10-01 15:56 ` Lukas Wunner
2022-10-01 16:10 ` Pali Rohár [this message]
2022-09-30 19:27 ` [PATCH V1 2/4] PCI/hotplug: Add GPIO PCIe hotplug driver Vidya Sagar
2022-09-30 19:27 ` [PATCH V1 3/4] PCI: tegra194: Add support to configure a pluggable slot Vidya Sagar
2022-09-30 19:27 ` [PATCH V1 4/4] PCI: tegra194: Enable GPIO based Hot-Plug support Vidya Sagar
2022-10-01 16:00 ` [PATCH V1 0/4] GPIO based PCIe " Lukas Wunner
2022-10-01 16:20 ` Pali Rohár
2022-10-01 23:50 ` Jonathan Derrick
2022-10-03 18:09 ` Bjorn Helgaas
2022-10-03 18:21 ` Pali Rohár
2022-10-03 19:18 ` Jonathan Derrick
2022-10-04 4:04 ` Vidya Sagar
2022-10-10 6:14 ` Vidya Sagar
2022-10-17 2:46 ` Vidya Sagar
2022-11-09 15:35 ` Manivannan Sadhasivam
2022-10-03 17:04 ` Rob Herring
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