Add description for optional device tree property
'brcm,pci-hotplug' for PCI hotplug feature.
Signed-off-by: Oza Pawandeep <oza.oza@xxxxxxxxxxxx>
Reviewed-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
diff --git a/Documentation/devicetree/bindings/pci/brcm,iproc-pcie.txt b/Documentation/devicetree/bindings/pci/brcm,iproc-pcie.txt
index b8e48b4..a3bad24 100644
--- a/Documentation/devicetree/bindings/pci/brcm,iproc-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/brcm,iproc-pcie.txt
@@ -72,6 +72,29 @@ Optional properties:
- brcm,pcie-msi-inten: Needs to be present for some older iProc platforms that
require the interrupt enable registers to be set explicitly to enable MSI
+Optional properties:
+- brcm,pci-hotplug: PCI hotplug feature is supported.
+
+If the brcm,pcie-hotplug property is present, the following properties become
+effective:
+
+- brcm,prsnt-gpio: Array of gpios, needs to be present if Hotplug is supported.
+
+PCI hotplug implementation is SOC/Board specific, and also it depends on
+how add-in card is designed (e.g. how many present pins are implemented).
+
+If x8 card is connected, then it might be possible that all the
+3 present pins could go low, or at least one pin goes low.
+
+If x4 card is connected, then it might be possible that 2 present
+pins go low, or at least one pin goes low.
+
+Example:
+brcm,prsnt-gpio: <&pca9505 32 1>, <&pca9505 33 1>;
+This is x4 connector: monitoring max 2 present lines.
+brcm,prsnt-gpio: <&pca9505 32 1>, <&pca9505 33 1>, <&pca9505 34 1>;
+This is x8 connector: monitoring max 3 present lines.
+
Example:
pcie0: pcie@18012000 {
compatible = "brcm,iproc-pcie";
--
1.9.1
