[v4,1/2] dt-bindings: usb: add "hub,interval" property
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Message ID 20191203101536.199222-1-ikjn@chromium.org
State Changes Requested
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Series
  • usb: override hub device bInterval with device
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Commit Message

Ikjoon Jang Dec. 3, 2019, 10:15 a.m. UTC
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@chromium.org>
---
 Documentation/devicetree/bindings/usb/usb-device.txt | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Rob Herring Dec. 16, 2019, 3:38 p.m. UTC | #1
On Tue, Dec 03, 2019 at 06:15:36PM +0800, Ikjoon Jang wrote:
> 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@chromium.org>
> ---
>  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.

'hub' is not a vendor.

'b-interval' instead.

Rob

Patch
diff mbox series

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 */