On Fri, Dec 07, 2018 at 06:27:43PM -0800, Thinh Nguyen wrote: > This patch adds a property to enable the controller to track the > frame number based on the reference clock. > > When operating in USB 2.0 mode, the peripheral controller uses the USB2 > PHY clocks to track the frame number. This prevents the controller from > suspending the USB2 PHY when the device goes into low power. Version > 1.80a of the DWC_usb31 peripheral controller introduces a way to track > frame number based on the reference clock instead. This feature allows > the controller to suspend the USB2 PHY when the device goes into low > power. This improves power saving for devices that have isochronous > endpoints. > > Signed-off-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx> > --- > Changes in v2: > - Revise property description > - Rename property from snps,enable-refclk-lpm to snps,enable-refclk-sof > > Documentation/devicetree/bindings/usb/dwc3.txt | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt > index b7e67edff9b2..01b948fff0eb 100644 > --- a/Documentation/devicetree/bindings/usb/dwc3.txt > +++ b/Documentation/devicetree/bindings/usb/dwc3.txt > @@ -101,6 +101,9 @@ Optional properties: > enable periodic ESS TX threshold. > - snps,refclk-period-ns: if set, this value informs the controller of the > reference clock period in nanoseconds. > + - snps,enable-refclk-sof: set to enable reference clock based frame number > + tracking while in low power, allowing the controller to > + suspend the PHY during low power states. This should be implied by the compatible string. > > - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated. > - snps,incr-burst-type-adjustment: Value for INCR burst type of GSBUSCFG0 > -- > 2.11.0 >
