[U-Boot] [PATCH] usb: gadget: composite: Correct recovery path for register

[Sam Protsenko]

+ Praneeth Bajjuri
+ Tom Rini
+ Rob Herring

On Tue, Feb 16, 2016 at 7:59 PM, Semen Protsenko
<semen.protsenko at linaro.org> wrote:
> From: Sam Protsenko <semen.protsenko at linaro.org>
>
> In case when usb_composite_register() failed once (for whatever reason),
> it will fail further even if all conditions are correct. Example:
>
>     => fastboot 2
>     Invalid Controller Index
>     couldn't find an available UDC
>     g_dnl_register: failed!, error: -19
>     exit not allowed from main input shell.
>
>     => fastboot 0
>     g_dnl_register: failed!, error: -22
>     exit not allowed from main input shell.
>
> Despite that 0 is correct index for USB controller, "fastboot 0" command
> will fail, because "composite" structure wasn't cleared properly on
> previous fail (on "fastboot 2" command).
>
> This patch fixes that erroneous behavior, allowing us to use composite
> even after previous failure.
>
> Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
> ---
>  drivers/usb/gadget/composite.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index 60f9272..d0ee784 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -1077,6 +1077,8 @@ static struct usb_gadget_driver composite_driver = {
>   */
>  int usb_composite_register(struct usb_composite_driver *driver)
>  {
> +       int res;
> +
>         if (!driver || !driver->dev || !driver->bind || composite)
>                 return -EINVAL;
>
> @@ -1084,7 +1086,11 @@ int usb_composite_register(struct usb_composite_driver *driver)
>                 driver->name = "composite";
>         composite = driver;
>
> -       return usb_gadget_register_driver(&composite_driver);
> +       res = usb_gadget_register_driver(&composite_driver);
> +       if (res != 0)
> +               composite = NULL;
> +
> +       return res;
>  }
>
>  /**
> --
> 2.7.0
>