On Fri, Mar 15, 2013 at 05:17:08PM +0200, Alexander Shishkin wrote: > > > Eg, for tablet or phone, the dr_mode may be "gadget", but the > > otg_capable = 1. > > No, because dr_mode indicates controller's capability, and not the > "current" mode of operation. Why would anyone want to put *that* in a > DT? > OK, now I totally understand your mind of this problem. In fact, dr_mode is NOT controller's capability, even at its original place: (Documentation/devicetree/bindings/usb/fsl-usb.txt or nvidia, tegra20-ehci.txt) dr_mode is the usb working mode. When we design USB system, the requirements are differ from products to products. The phone/tablet device may only wants itself as gadget device, it needs to be no-response when there is a usb device plug in (eg usb keyboard with Micro B-to-A cable). The car entertainment system or other Standard-A port system do not want to be enumerated when it plugs to notebook using Standard A-to-A cable. So, currently, even most of controllers are otg-capable, still most of designs are one working mode designed. The reason why we design the dr_mode is that we want controller working mode to be decided by DT without re-compile the kernel by build out the host/gadget driver. -- Best Regards, Peter Chen -- 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
