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 ?
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) ?
The common driver will have to handle the suspend/resume in an
homogenous way.
If the gadget driver is removed, the pullup should be pulled low.
All of this work for only 2 drivers looks overkill to me.
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.
Cheers.
--
Robert
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