[V12,08/12] dt-bindings: Add PCIe supports-clkreq property

Message ID	20190701124010.7484-9-vidyas@nvidia.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> TLS: TLSv1.2, DES-CBC3-SHA) id <B5d19ff750000>; Mon, 01 Jul 2019 05:41:25 -0700 From: Vidya Sagar <vidyas@nvidia.com> To: <lorenzo.pieralisi@arm.com>, <bhelgaas@google.com>, <robh+dt@kernel.org>, <mark.rutland@arm.com>, <thierry.reding@gmail.com>, <jonathanh@nvidia.com>, <kishon@ti.com>, <catalin.marinas@arm.com>, <will.deacon@arm.com>, <jingoohan1@gmail.com>, <gustavo.pimentel@synopsys.com> Subject: [PATCH V12 08/12] dt-bindings: Add PCIe supports-clkreq property Date: Mon, 1 Jul 2019 18:10:06 +0530 Message-ID: <20190701124010.7484-9-vidyas@nvidia.com> In-Reply-To: <20190701124010.7484-1-vidyas@nvidia.com> References: <20190701124010.7484-1-vidyas@nvidia.com> MIME-Version: 1.0 Precedence: list Cc: devicetree@vger.kernel.org, mmaddireddy@nvidia.com, kthota@nvidia.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, mperttunen@nvidia.com, linux-tegra@vger.kernel.org, digetx@gmail.com, vidyas@nvidia.com, linux-arm-kernel@lists.infradead.org, sagar.tv@gmail.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org
Series	Add Tegra194 PCIe support \| expand [V12,00/12] Add Tegra194 PCIe support [V12,01/12] PCI: Add #defines for some of PCIe spec r4.0 features [V12,02/12] PCI: Disable MSI for Tegra root ports [V12,03/12] PCI: dwc: Perform dbi regs write lock towards the end [V12,04/12] PCI: dwc: Move config space capability search API [V12,05/12] PCI: dwc: Add ext config space capability search API [V12,06/12] dt-bindings: PCI: designware: Add binding for CDM register check [V12,07/12] PCI: dwc: Add support to enable CDM register check [V12,08/12] dt-bindings: Add PCIe supports-clkreq property [V12,09/12] dt-bindings: PCI: tegra: Add device tree support for Tegra194 [V12,10/12] dt-bindings: PHY: P2U: Add Tegra194 P2U block [V12,11/12] phy: tegra: Add PCIe PIPE2UPHY support [V12,12/12] PCI: tegra: Add Tegra194 PCIe support

Message ID

20190701124010.7484-9-vidyas@nvidia.com (mailing list archive)

State

New, archived

Headers

From: Vidya Sagar <vidyas@nvidia.com>
To: <lorenzo.pieralisi@arm.com>, <bhelgaas@google.com>, <robh+dt@kernel.org>,
 <mark.rutland@arm.com>, <thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
 <kishon@ti.com>, <catalin.marinas@arm.com>, <will.deacon@arm.com>,
 <jingoohan1@gmail.com>, <gustavo.pimentel@synopsys.com>
Subject: [PATCH V12 08/12] dt-bindings: Add PCIe supports-clkreq property
Date: Mon, 1 Jul 2019 18:10:06 +0530
Message-ID: <20190701124010.7484-9-vidyas@nvidia.com>
In-Reply-To: <20190701124010.7484-1-vidyas@nvidia.com>
References: <20190701124010.7484-1-vidyas@nvidia.com>
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Cc: devicetree@vger.kernel.org, mmaddireddy@nvidia.com, kthota@nvidia.com,
 linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
 mperttunen@nvidia.com,
 linux-tegra@vger.kernel.org, digetx@gmail.com, vidyas@nvidia.com,
 linux-arm-kernel@lists.infradead.org, sagar.tv@gmail.com
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Series

Add Tegra194 PCIe support | expand

Commit Message

Vidya Sagar July 1, 2019, 12:40 p.m. UTC

Some host controllers need to know the existence of clkreq signal routing to
downstream devices to be able to advertise low power features like ASPM L1
substates. Without clkreq signal routing being present, enabling ASPM L1 sub
states might lead to downstream devices falling off the bus. Hence a new device
tree property 'supports-clkreq' is added to make such host controllers
aware of clkreq signal routing to downstream devices.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Thierry Reding <treding@nvidia.com>
---
Changes since [v11]:
* Rebased on top of linux-next top of the tree

Changes since [v10]:
* None

Changes since [v9]:
* None

Changes since [v8]:
* None

Changes since [v7]:
* None

Changes since [v6]:
* None

Changes since [v5]:
* s/Documentation\/devicetree/dt-bindings/ in the subject

Changes since [v4]:
* None

Changes since [v3]:
* Rebased on top of linux-next top of the tree

Changes since [v2]:
* None

Changes since [v1]:
* This is a new patch in v2 series

 Documentation/devicetree/bindings/pci/pci.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt
index 2a5d91024059..29bcbd88f457 100644
--- a/Documentation/devicetree/bindings/pci/pci.txt
+++ b/Documentation/devicetree/bindings/pci/pci.txt
@@ -27,6 +27,11 @@  driver implementation may support the following properties:
 - reset-gpios:
    If present this property specifies PERST# GPIO. Host drivers can parse the
    GPIO and apply fundamental reset to endpoints.
+- supports-clkreq:
+   If present this property specifies that CLKREQ signal routing exists from
+   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.
 
 PCI-PCI Bridge properties
 -------------------------

[V12,08/12] dt-bindings: Add PCIe supports-clkreq property

Commit Message

Patch