On 5/20/11, Robert Jarzmik <robert.jarzmik@xxxxxxx> wrote: > On 05/18/2011 02:06 PM, Dmitry Eremin-Solenikov wrote: >> Hello, colleagues, >> >> There are several PXA platforms which on the UDC tranceiver part have >> a pullup pin to support connect/disconnect but no VBUS pin to detect >> host presense. Currently such platforms are supported through udc driver >> itself. I'd like to clean that part of pxa25x_udc/pxa27x_udc drivers and >> to move gpio pullup handling to tranceiver. > So, you want to concentrate USB pullup handling, right ? Basically I'd like to cleanup this part of pxa udc drivers. >> My question is what would be better: to extend gpio-vbus to work w/o >> VBUS pin or to write new transceiver driver only handling gpio-pullup? > > My personnal feeling is neither, let them be. The generic pullup would > have to ask itself : > - should the pullup be applied on D+ (on USB 2.0 and 3.0 devices) ? > - should the pullup be applied on D- (on USB 1.1 devices) ? gpio-vbus driver doesn't do this. It simply handles D+ pullup. I think I'd start with simple D+ pullup driver and the one may add D- functionality if required. > The common driver will have to handle the suspend/resume in an > homogenous way. Do pxa25x_udc/pxa27x_udc handle pullup during suspend/resume? > If the gadget driver is removed, the pullup should be pulled low. > > All of this work for only 2 drivers looks overkill to me. 3 boards only from PXA. I don't know about other platforms/soc-families. > And if you want to gather it in a driver, "gpio-vbus" purpose was to > handle VBUS sensing, ie. power presence on +5V/Gnd lines. The D+ > handling was not part of its duties, and you'll probably end up with a > new driver, which is ... overkill IMHO. gpio-vbus handles D+ already (except suspend/resume). -- With best wishes Dmitry -- 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
