On Tue, Nov 01, 2016 at 01:18:17PM +0200, Felipe Balbi wrote: > > Hi, > > John Youn <john.y...@synopsys.com> writes: > >>>> John Youn <johny...@synopsys.com> writes: > >>>>> Add interrupt moderation interval binding for dwc3. > >>>>> > >>>>> Signed-off-by: John Youn <johny...@synopsys.com> > >>>>> --- > >>>>> Documentation/devicetree/bindings/usb/dwc3.txt | 1 + > >>>>> 1 file changed, 1 insertion(+) > >>>>> > >>>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt > >>>>> b/Documentation/devicetree/bindings/usb/dwc3.txt > >>>>> index e3e6983..17de9fc 100644 > >>>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt > >>>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt > >>>>> @@ -53,6 +53,7 @@ Optional properties: > >>>>> - snps,quirk-frame-length-adjustment: Value for GFLADJ_30MHZ field of > >>>>> GFLADJ > >>>>> register for post-silicon frame length adjustment when the > >>>>> fladj_30mhz_sdbnd signal is invalid or incorrect. > >>>>> + - snps,imod_interval: the interrupt moderation interval. > >>>> > >>>> on top of all other comments, what's the unit here? nanoseconds? clock > >>>> cycles? > >>>> > >>> > >>> Number of 250 ns intervals. I'll update the description to clarify. > >> > >> it's probably better to add it in nanoseconds itself, then let driver > >> compute register value with DIV_ROUND_UP() > >> > > > > I'm fine with it either way, but I think "increments of 250 ns" is > > slightly cleaner in that it reflects the exact settings that are > > possible and documented, and also fits neatly into a u16. > > I don't know, I'll leave this to Mark and the other devicetree folks, > but I remember there was a preference of not passing register values via > devicetree. What if a following HW revision decides to change 250ns > increments to 125ns increments? > > Mark?
Generally, directly human-readable units are preferable, with some validation/reporting left to the driver for cases the HW cannot support. In this case, some *-interval-ns property would be better. That said, it sounds like we're all agreed that we don't need this property for now. :) Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
