Re: [PATCH] HID: wacom: add USB_HID dependency

[Arnd Bergmann <arnd@arndb.de>]

On Fri, Jul 28, 2017 at 4:07 PM, Jason Gerecke <killertofu@gmail.com> wrote:
> On July 28, 2017 6:18:00 AM PDT, Arnd Bergmann <arnd@arndb.de> wrote:
>>The driver has gained a compile-time dependency that we should
>>express in Kconfig to avoid this link error:
>>
>
> Would conditional compilation be an acceptable alternative to adding
> a dependency? The USB_HID code is only used to check if the driver
> is working with a USB device. With USB_HID disabled, there's no need
> for the check so there's no need for the dependency.

I think that should work, e.g. you could replace the hid_is_using_ll_driver
and 'extern' defintions with a helper per ll-driver like

#ifdef CONFIG_USB_HID
extern bool hid_is_using_usb_driver(struct hid_device *hdev)
#else
static inline bool hid_is_using_usb_driver(struct hid_device *hdev)
{
       return false;
}
#endif

but is it worth it to avoid the dependency?

       Arnd