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>
Cc: <digetx@gmail.com>, <mperttunen@nvidia.com>,
<linux-pci@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>, <kthota@nvidia.com>,
<mmaddireddy@nvidia.com>, <vidyas@nvidia.com>,
<sagar.tv@gmail.com>
Subject: [PATCH V14 09/13] dt-bindings: Add PCIe supports-clkreq property
Date: Wed, 24 Jul 2019 23:18:20 +0530 [thread overview]
Message-ID: <20190724174824.20933-10-vidyas@nvidia.com> (raw)
In-Reply-To: <20190724174824.20933-1-vidyas@nvidia.com>
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 substates might lead to downstream devices being disconnected
from 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>
---
V14:
* s/falling off the bus/being disconnected from the bus/ in commit message.
V13:
* None
V12:
* Rebased on top of linux-next top of the tree
V11:
* None
V10:
* None
V9:
* None
V8:
* None
V7:
* None
V6:
* s/Documentation\/devicetree/dt-bindings/ in the subject
V5:
* None
V4:
* Rebased on top of linux-next top of the tree
V3:
* None
V2:
* 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
-------------------------
--
2.17.1
next prev parent reply other threads:[~2019-07-24 17:49 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-24 17:48 [PATCH V14 00/13] PCI: tegra: Add Tegra194 PCIe support Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 01/13] PCI: Add #defines for some of PCIe spec r4.0 features Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 02/13] PCI: Disable MSI for Tegra root ports Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 03/13] PCI: dwc: Perform dbi regs write lock towards the end Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 04/13] PCI: dwc: Move config space capability search API Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 05/13] PCI: dwc: Add ext " Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 06/13] PCI: dwc: Export dw_pcie_wait_for_link() API Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 07/13] dt-bindings: PCI: designware: Add binding for CDM register check Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 08/13] PCI: dwc: Add support to enable " Vidya Sagar
2019-07-24 17:48 ` Vidya Sagar [this message]
2019-07-24 17:48 ` [PATCH V14 10/13] dt-bindings: PCI: tegra: Add device tree support for Tegra194 Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 11/13] dt-bindings: PHY: P2U: Add Tegra194 P2U block Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 12/13] phy: tegra: Add PCIe PIPE2UPHY support Vidya Sagar
2019-07-24 17:48 ` [PATCH V14 13/13] PCI: tegra: Add Tegra194 PCIe support Vidya Sagar
2019-07-30 4:00 ` Vidya Sagar
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