From 7b31a72e7195aebd620d504f28b97ad8398e95ec Mon Sep 17 00:00:00 2001 From: Vidya Sagar Date: Tue, 13 Aug 2019 17:06:23 +0530 Subject: dt-bindings: Add PCIe supports-clkreq property 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 Signed-off-by: Lorenzo Pieralisi Reviewed-by: Rob Herring Reviewed-by: Thierry Reding --- Documentation/devicetree/bindings/pci/pci.txt | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/devicetree/bindings/pci/pci.txt') 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 ------------------------- -- cgit v1.2.3