[U-Boot] [PATCH v2] sunxi: Avoid any assumption between musb gadget and host but fallback to host

[Hans de Goede]

Hi,

On 04-04-15 15:42, Paul Kocialkowski wrote:
> Le dimanche 29 mars 2015 à 13:18 +0200, Hans de Goede a écrit :
>> Hi,
>>
>> On 28-03-15 18:26, Paul Kocialkowski wrote:
>>> musb might be used in gadget mode on sunxi, so we don't want to assume anything
>>> related to host mode, especially USB keyboard support. Thus, there is no reason
>>> to keep USB_KEYBOARD always enabled and in Kconfig: it is much better fit to
>>> enable it in the common sunxi config header, when needed (some devices also have
>>> no USB support at all).
>>>
>>> In case gadget mode is not explicitly enabled, this will fallback to host mode.
>>>
>>> Signed-off-by: Paul Kocialkowski <contact at paulk.fr>
>>
>> Nack, I'm not going to take any patch which removes config USB_KEYBOARD,
>> having USB_KEYBOARD always enabled on devices with usb host capability
>> causes a significant penalty in boot time, and some people may want to turn
>> it off because of that.
>
> Actually, I said I would give up on this, but there are still parts of
> that patch that I need for USB gadget (not related to USB keyboard).
>
> Regarding USB keyboard, the best solution IMO would be to set it
> disabled by default in board/sunxi/Kconfig (both because of the boot
> time penality and because it's not relevant when using gadget mode) and
> have it enabled individually in each configs/*_defconfig that uses USB
> in host mode.

We try to offer the best ootb experience with the defconfigs and many
users will not have serial consoles attached, so we really want
usb-keyboard by default. Actually we can currently already use
host mode on ehci and gadget mode on musb and then we still want
usb-keyboard and that is how I expect the majority of the boards
to eventually be configured ootb.

The only time when we do not want USB_KEYBOARD is when we've no
usb hosts at all because that will cause linking errors, this
should go away once we move over usb to the device model which
will happen soon.

I'm happy to take patches you need to enable gadget mode, but I
do not think it is a good idea to flip the the default and then
add CONFIG_USB_KEYBOARD=y to pretty much every one of our 55
defconfig files.

Regards,

Hans