usbgadget autostart: add usbgadget.fastboot_bbu to automatically export bbu handlers ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

usbgadget: only set to peripheral mode when error checking is done ...

Only begin to modify the hardware when the obious errors have been
checked.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

usbgadget: do not register when no functions present ...

registering a multifunction device makes only sense when there's
at least one function configured. Just return otherwise.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

usbgadget: autostart: Handle errors in file list gracefully ...

file_list_parse() can fail and returns an error pointer. Print
an error message when it fails and also set to NULL again so
that usb_multi_register() does not stumble upon the error pointer.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

usb: gadget: autostart: properly release f_multi_opts ...

the same as for usb gadget autostarter.

|commit 2b9bcff
|Author: Sascha Hauer <s.hauer@pengutronix.de>
|Date:   Fri Jan 20 10:03:45 2017 +0100
|
|    usb: gadget: properly release f_multi_opts
|
|    The usbgadget commands uses statically allocated f_multi_opts and passes
|    this to usb_multi_register(). These f_multi_opts are of course no
|    longer valid when we leave the usbgadget command. Luckily we do not use
|    the data after we left the usbgadget command, so this never has been a
|    problem. However, f_multi_opts has some allocated members which we can
|    not free anymore on gadget unregistration because we no longer have the
|    pointer to them.
|
|    Fix this by adding a release function to struct f_multi_opts. This way
|    we can allocate all memory dynamically and properly free it when not
|    used anymore.
|
|    Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

usb: gadget: set otg to peripheral mode on autostart ...

we won't be able to start if otg is not properly configured.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

usb: gadget: start usbgadget automatically ...

... if global variable configured to do it.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>