[PATCH] HID: generic: Check other drivers match callback from __check_hid_generic

[Hans de Goede <hdegoede@redhat.com>]

__check_hid_generic is used to check if there is a driver, other then
the hid-generic driver, which wants to handle the hid-device, in which
case hid_generic_match() will return false so that the other driver can
bind.

But what if the other driver also has a match callback and that indicates
it does not want to handle the device? Then hid-generic should bind to it
and thus hid_generic_match() should NOT return false in that case.

This commit makes __check_hid_generic check if a matching driver has
a match callback and if it does makes its check this, so that
hid-generic will bind to devices which have a matching other driver,
but that other driver's match callback rejects the device.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
This patch was written while fixing the issues with hid-ite on the
Acer SW5-012, where we only want to bind to one interface. In that
specific case this change is not necessary because hid-multitouch will
pick the hid-device which hid-ite's match callback is rejecting.
---
 drivers/hid/hid-generic.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-generic.c b/drivers/hid/hid-generic.c
index f9db991d3c5a..fe3ca7612750 100644
--- a/drivers/hid/hid-generic.c
+++ b/drivers/hid/hid-generic.c
@@ -31,7 +31,13 @@ static int __check_hid_generic(struct device_driver *drv, void *data)
 	if (hdrv == &hid_generic)
 		return 0;
 
-	return hid_match_device(hdev, hdrv) != NULL;
+	if (!hid_match_device(hdev, hdrv))
+		return 0;
+
+	if (!hdrv->match)
+		return 1;
+
+	return hdrv->match(hdev, false);
 }
 
 static bool hid_generic_match(struct hid_device *hdev,
-- 
2.23.0