HID: core: remove the absolute need of hid_have_special_driver[]

Most HID devices behave properly when they are used with hid-generic.
Since kernel v4.12, we do not poll for input reports at plug in, so
hid-generic should behave properly with all HID devices.

There has been a long standing list of HID devices that have a special
driver. It used to be just a few, but with time, this list went too big,
and we can not ask users to know which HID special driver will pick up
their device.

We can teach hid-generic to be nice with others. If a device is not
explicitly marked with HID_QUIRK_HAVE_SPECIAL_DRIVER, we can allow
hid-generic to pick up the device as long as no other loaded HID driver
will match the device.

When the special driver appears, hid-generic can step back and let
the special driver handling the device. In case this special driver
is removed, this good old pal of hid-generic will rebind to the device.

This basically makes the list hid_have_special_driver[] useless. It
still allows to not see a hid-generic driver bound and removed during
boot, so we can keep it around.

This will also help other people to have a special HID driver without
the need of recompiling hid-core.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/hid.h b/include/linux/hid.h
index 83df331576a5..39cdeb205caa 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -672,6 +672,7 @@ struct hid_usage_id {
  * 	      to be called)
  * @dyn_list: list of dynamically added device ids
  * @dyn_lock: lock protecting @dyn_list
+ * @match: check if the given device is handled by this driver
  * @probe: new device inserted
  * @remove: device removed (NULL if not a hot-plug capable driver)
  * @report_table: on which reports to call raw_event (NULL means all)
@@ -684,6 +685,8 @@ struct hid_usage_id {
  * @input_mapped: invoked on input registering after mapping an usage
  * @input_configured: invoked just before the device is registered
  * @feature_mapping: invoked on feature registering
+ * @bus_add_driver: invoked when a HID driver is about to be added
+ * @bus_removed_driver: invoked when a HID driver has been removed
  * @suspend: invoked on suspend (NULL means nop)
  * @resume: invoked on resume if device was not reset (NULL means nop)
  * @reset_resume: invoked on resume if device was reset (NULL means nop)
@@ -712,6 +715,7 @@ struct hid_driver {
 	struct list_head dyn_list;
 	spinlock_t dyn_lock;
 
+	bool (*match)(struct hid_device *dev, bool ignore_special_driver);
 	int (*probe)(struct hid_device *dev, const struct hid_device_id *id);
 	void (*remove)(struct hid_device *dev);
 
@@ -737,6 +741,8 @@ struct hid_driver {
 	void (*feature_mapping)(struct hid_device *hdev,
 			struct hid_field *field,
 			struct hid_usage *usage);
+	void (*bus_add_driver)(struct hid_driver *driver);
+	void (*bus_removed_driver)(struct hid_driver *driver);
 #ifdef CONFIG_PM
 	int (*suspend)(struct hid_device *hdev, pm_message_t message);
 	int (*resume)(struct hid_device *hdev);
@@ -815,6 +821,8 @@ extern bool hid_ignore(struct hid_device *);
 extern int hid_add_device(struct hid_device *);
 extern void hid_destroy_device(struct hid_device *);
 
+extern struct bus_type hid_bus_type;
+
 extern int __must_check __hid_register_driver(struct hid_driver *,
 		struct module *, const char *mod_name);
 
@@ -865,6 +873,8 @@ bool hid_match_one_id(const struct hid_device *hdev,
 		      const struct hid_device_id *id);
 const struct hid_device_id *hid_match_id(const struct hid_device *hdev,
 					 const struct hid_device_id *id);
+const struct hid_device_id *hid_match_device(struct hid_device *hdev,
+					     struct hid_driver *hdrv);
 s32 hid_snto32(__u32 value, unsigned n);
 __u32 hid_field_extract(const struct hid_device *hid, __u8 *report,
 		     unsigned offset, unsigned n);