From: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
To: andersson@kernel.org, robh@kernel.org,
manivannan.sadhasivam@linaro.org, krzk@kernel.org,
helgaas@kernel.org
Cc: linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
lpieralisi@kernel.org, kw@linux.com, conor+dt@kernel.org,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree-spec@vger.kernel.org, quic_vbadigan@quicinc.com,
krishna.chundru@oss.qualcomm.com
Subject: [PATCH] schemas: pci: Document PCIe T_POWER_ON
Date: Thu, 6 Nov 2025 17:09:51 +0530 [thread overview]
Message-ID: <20251106113951.844312-1-krishna.chundru@oss.qualcomm.com> (raw)
From PCIe r6, sec 5.5.4 & sec 5.5.5 T POWER_ON is the minimum amount
of time that each component must wait in L1.2.Exit after sampling CLKREQ#
asserted before actively driving the interface to ensure no device is ever
actively driving into an unpowered component and these values are based on
the components and AC coupling capacitors used in the connection linking
the two components.
Certain controllers may need to program this before enumeration, such
controllers can use this property to program it.
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
dtschema/schemas/pci/pci-bus-common.yaml | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/dtschema/schemas/pci/pci-bus-common.yaml b/dtschema/schemas/pci/pci-bus-common.yaml
index 5257339..bbe5510 100644
--- a/dtschema/schemas/pci/pci-bus-common.yaml
+++ b/dtschema/schemas/pci/pci-bus-common.yaml
@@ -152,6 +152,15 @@ properties:
This property is invalid in host bridge nodes.
maxItems: 1
+ t-power-on-us:
+ description:
+ The minimum amount of time that each component must wait in
+ L1.2.Exit after sampling CLKREQ# asserted before actively driving
+ the interface to ensure no device is ever actively driving into an
+ unpowered component. This value is based on the components and AC
+ coupling capacitors used in the connection linking the two
+ components(PCIe r6.0, sec 5.5.4).
+
supports-clkreq:
description:
If present this property specifies that CLKREQ signal routing exists from
--
2.34.1
next reply other threads:[~2025-11-06 11:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-06 11:39 Krishna Chaitanya Chundru [this message]
2025-11-06 12:38 ` [PATCH] schemas: pci: Document PCIe T_POWER_ON Manivannan Sadhasivam
2025-11-06 14:07 ` Krishna Chaitanya Chundru
-- strict thread matches above, loose matches on Subject: below --
2025-11-10 11:25 Krishna Chaitanya Chundru
2025-11-10 13:13 ` Krishna Chaitanya Chundru
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