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

[Arnd Bergmann]

On Fri, Jul 28, 2017 at 4:24 PM, Jason Gerecke <killertofu@xxxxxxxxx> wrote:
> On Fri, Jul 28, 2017 at 7:18 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
>> On Fri, Jul 28, 2017 at 4:07 PM, Jason Gerecke <killertofu@xxxxxxxxx> wrote:

>> #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
>
> I was thinking something more along the lines of the following since
> the idea of per-transport helper functions was dismissed earlier:
>
> #ifdef CONFIG_USB_HID
>                 if (hid_is_using_ll_driver(wacom->hdev, &usb_hid_driver)) {

I would consider that rather ugly, a driver shouldn't really use
#ifdef like this, but you can hide stuff like this in a header. The method
I proposed also has the advantage of avoiding exporting the
usb_hid_driver object. Drivers shouldn't really need to access this,
and wacom_sys.c is the only remaining user of the export.

      Arnd