Hi Paul, On Sat, Apr 12, 2014 at 02:25:27AM +0800, Paul Zimmerman wrote: > > From: Pratyush Anand [mailto:pratyush.anand@xxxxxxxxx] > > Sent: Friday, April 11, 2014 11:06 AM > > > > On Fri, Apr 11, 2014 at 11:24 PM, Felipe Balbi <balbi@xxxxxx> wrote: > > > On Fri, Apr 11, 2014 at 03:50:03PM +0530, Pratyush Anand wrote: > > >> If a dwc3 host implementation is lpm capable then enable lpm_capable in > > >> device tree. > > >> > > >> Signed-off-by: Pratyush Anand <pratyush.anand@xxxxxx> > > >> --- > > >> Documentation/devicetree/bindings/usb/dwc3.txt | 2 ++ > > >> 1 file changed, 2 insertions(+) > > >> > > >> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt > > b/Documentation/devicetree/bindings/usb/dwc3.txt > > >> index 7a95c65..a7a48f1 100644 > > >> --- a/Documentation/devicetree/bindings/usb/dwc3.txt > > >> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt > > >> @@ -10,6 +10,7 @@ Required properties: > > >> > > >> Optional properties: > > >> - tx-fifo-resize: determines if the FIFO *has* to be reallocated. > > >> + - lpm-capable: determines if xhci host is lpm capable > > >> > > >> This is usually a subnode to DWC3 glue to which it is connected. > > >> > > >> @@ -19,4 +20,5 @@ dwc3@4a030000 { > > >> interrupts = <0 92 4> > > >> usb-phy = <&usb2_phy>, <&usb3,phy>; > > >> tx-fifo-resize; > > >> + lpm-capable; > > > > > > I think there's a way to detect this in runtime but I can't seem to find > > > it on databook. Perhaps check with your IP designer/integrator which > > > HWPARAMS register we can poke to verify core was configured with LPM ? > > > > I too tried to look into databook first, But could not find. Lets see, what Paul > > says. > > Hi guys, > > The "Power Management" section of the databook talks about hardware- > controlled LPM. It's section 12.4 in the latest databook. LPM is a > standard xHCI feature, so you can look at the xHCI spec to find the > info about it. > > In the xHCI spec, section 4.23.5.1.1 "USB2 LPM Support" says this: > > "This section applies only if a USB2 xHCI Supported Protocol Capability > structure (section 7.2) is declared (i.e. the Major Revision field = 02h)." > > And if you look at section 7.2.2.1.3.2 "USB2", it shows that bit 19 in > the Protocol Defined field of the USB2 xHCI Supported Protocol Capability > structure indicates whether the controller supports hardware-controlled > LPM. Yes, for USB2 LPM we can use it. But These patches are mainly for USB3 LPM where we program U1/U2 inactivity timeout. I am not sure if same bit can be used for USB3 LPM. Regards Pratyush > > -- > Paul -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
