On Tue, Jan 22, 2019 at 10:37:17AM +0000, Jun Li wrote: > The USB3 suspend_clk input replaces pipe3_rx_pclk as a clock > source to a small part of the USB3 core that operates when the > SS PHY is in its lowest power(P3) state, and therefore does > not provide a clock. The power down scale specifies how many > suspend_clk periods fit into a 16 KHz clock period, details > can see DWC3 databook register GCTL.PWRDNSCALE. > > Signed-off-by: Li Jun <jun.li@xxxxxxx> > --- > Documentation/devicetree/bindings/usb/dwc3.txt | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt > index 3e4c38b..d1c8b62 100644 > --- a/Documentation/devicetree/bindings/usb/dwc3.txt > +++ b/Documentation/devicetree/bindings/usb/dwc3.txt > @@ -102,6 +102,12 @@ Optional properties: > more than one value, which means undefined length INCR burst type > enabled. The values can be 1, 4, 8, 16, 32, 64, 128 and 256. > > + - snps,power-down-scale: Power down scale field specifies how many suspend_clk > + periods fit into a 16 Khz clock period. When performing > + the division, round up the remainder. Suspend clock is > + from 32kHz to 125MHz, means the value range is 2~8000. > + (details see DWC_usb3 databook register GCTL.PWRDNSCALE). > + Sounds like the suspend_clk should be provided as a clock input so you can calculate this value. > - in addition all properties from usb-xhci.txt from the current directory are > supported as well > > -- > 2.7.4 >
