Add "hub,interval" property to usb-device, so hub device can override
endpoint descriptor's bInterval.
When we know reducing autosuspend delay for built-in HIDs is better for
power saving, we can reduce it to the optimal value. But if a parent hub
has a long bInterval, mouse lags a lot from more frequent autosuspend.
So this enables overriding bInterval for a hard wired hub device only
when we know that reduces the power consumption.
Signed-off-by: Ikjoon Jang <ikjn@xxxxxxxxxxxx>
---
Documentation/devicetree/bindings/usb/usb-device.txt | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/Documentation/devicetree/bindings/usb/usb-device.txt b/Documentation/devicetree/bindings/usb/usb-device.txt
index 036be172b1ae..44bef2ff2704 100644
--- a/Documentation/devicetree/bindings/usb/usb-device.txt
+++ b/Documentation/devicetree/bindings/usb/usb-device.txt
@@ -66,6 +66,9 @@ Required properties for host-controller nodes with device nodes:
- #size-cells: shall be 0
+Optional properties for hub nodes
+- hub,interval: bInterval of status change endpoint. The range is 1-255.
+
Example:
&usb1 { /* host controller */
@@ -75,6 +78,7 @@ Example:
hub@1 { /* hub connected to port 1 */
compatible = "usb5e3,608";
reg = <1>;
+ hub,interval = <8>;
};
device@2 { /* device connected to port 2 */
--
2.24.0.393.g34dc348eaf-goog
