We already have the possibility to force not binding to hid-generic and
rely on a dedicated driver, but we couldn't do the other way around.

This is useful for BPF programs where we are fixing the report descriptor
and the events, but want to avoid a specialized driver to come after BPF
which would unwind everything that is done there.

Signed-off-by: Benjamin Tissoires <bent...@kernel.org>

---

changes in v2:
- rely on hdev->quirks for that instead of a new struct for hid_driver
---
 drivers/hid/hid-core.c    | 5 +++--
 drivers/hid/hid-generic.c | 3 +++
 include/linux/hid.h       | 2 ++
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 37e52759a931..bf63e2819baf 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2665,9 +2665,10 @@ static bool hid_check_device_match(struct hid_device 
*hdev,
        /*
         * hid-generic implements .match(), so we must be dealing with a
         * different HID driver here, and can simply check if
-        * hid_ignore_special_drivers is set or not.
+        * hid_ignore_special_drivers or HID_QUIRK_IGNORE_SPECIAL_DRIVER
+        * are set or not.
         */
-       return !hid_ignore_special_drivers;
+       return !hid_ignore_special_drivers && !(hdev->quirks & 
HID_QUIRK_IGNORE_SPECIAL_DRIVER);
 }
 
 static int __hid_device_probe(struct hid_device *hdev, struct hid_driver *hdrv)
diff --git a/drivers/hid/hid-generic.c b/drivers/hid/hid-generic.c
index f9db991d3c5a..88882c1bfffe 100644
--- a/drivers/hid/hid-generic.c
+++ b/drivers/hid/hid-generic.c
@@ -40,6 +40,9 @@ static bool hid_generic_match(struct hid_device *hdev,
        if (ignore_special_driver)
                return true;
 
+       if (hdev->quirks & HID_QUIRK_IGNORE_SPECIAL_DRIVER)
+               return true;
+
        if (hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)
                return false;
 
diff --git a/include/linux/hid.h b/include/linux/hid.h
index d41fa18f1e03..b3a9586363c9 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -359,6 +359,7 @@ struct hid_item {
  * | @HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP:
  * | @HID_QUIRK_HAVE_SPECIAL_DRIVER:
  * | @HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE:
+ * | @HID_QUIRK_IGNORE_SPECIAL_DRIVER
  * | @HID_QUIRK_FULLSPEED_INTERVAL:
  * | @HID_QUIRK_NO_INIT_REPORTS:
  * | @HID_QUIRK_NO_IGNORE:
@@ -384,6 +385,7 @@ struct hid_item {
 #define HID_QUIRK_HAVE_SPECIAL_DRIVER          BIT(19)
 #define HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE BIT(20)
 #define HID_QUIRK_NOINVERT                     BIT(21)
+#define HID_QUIRK_IGNORE_SPECIAL_DRIVER                BIT(22)
 #define HID_QUIRK_FULLSPEED_INTERVAL           BIT(28)
 #define HID_QUIRK_NO_INIT_REPORTS              BIT(29)
 #define HID_QUIRK_NO_IGNORE                    BIT(30)

-- 
2.46.0


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