Hi, Richard Zhao writes: > On Tue, Jul 03, 2012 at 10:22:37AM +0800, Peter Chen wrote: > > > Hmm. I think it'd be reasonable to use dr_mode like the other bindings, > > > and have the default case be decided by the ID pin when dr_mode isn't > > > specified. Having different defaults for different bindings seems pretty > > > reasonable to me. > > > > As far as I know, there is no USB Spec says the ID value should be > > used at device or host mode. At USB device and host driver, there > > should be NO ID related things, that is to say device or host driver > > should not care ID is grounded or floated, as ID may be grounded > > at device mode, and high at host mode for different board design. > > ID interrupt should only be enabled when dr_mode = otg; > I don't quite understand your point. All the discussions are based > on otg controllers. > > > > Board design and customized usage (user may want to use only device mode > > for otg capable port) makes what USB role will be used > > at driver, so dr_mode at dts (or pdata->dr_mode at non-dt solution) can make > > the decision for driver how USB role will be used. > That's the case we need the property. But for fine otg hw design, we > don't need the property, right? > > And to decide whether it's otg controller or not, the driver read the > capability registers. > A user may wish to restrict even a 'fine otg hw design' to be used in pure host or device mode. That's where the dr_mode property jumps in. Lothar Waßmann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstraße 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Geschäftsführer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info@xxxxxxxxxxxxxxxxxxx ___________________________________________________________ -- 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
