> -----Original Message----- > From: Rob Herring <robh@xxxxxxxxxx> > Sent: 2019年2月23日 8:33 > To: Jun Li <jun.li@xxxxxxx> > Cc: mark.rutland@xxxxxxx; balbi@xxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; > devicetree@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx> > Subject: Re: [PATCH 1/2] Documentation: usb: dwc3: add power down clock scale > property > > 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. Yes, I will go this approach by update dts with suspend_clk of dwc3 Thanks Li Jun > > > - in addition all properties from usb-xhci.txt from the current directory are > > supported as well > > > > -- > > 2.7.4 > >
