Commit e04a0442 authored by Benjamin Tissoires's avatar Benjamin Tissoires Committed by Jiri Kosina
Browse files

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: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent f745d162

drivers/hid/hid-core.c

+48 −28
Original line number Diff line number Diff line
@@ -830,31 +830,6 @@ static int hid_scan_report(struct hid_device *hid) 
		break;

	}



	/* fall back to generic driver in case specific driver doesn't exist */

	switch (hid->group) {

	case HID_GROUP_MULTITOUCH_WIN_8:

		/* fall-through */

	case HID_GROUP_MULTITOUCH:

		if (!IS_ENABLED(CONFIG_HID_MULTITOUCH))

			hid->group = HID_GROUP_GENERIC;

		break;

	case HID_GROUP_SENSOR_HUB:

		if (!IS_ENABLED(CONFIG_HID_SENSOR_HUB))

			hid->group = HID_GROUP_GENERIC;

		break;

	case HID_GROUP_RMI:

		if (!IS_ENABLED(CONFIG_HID_RMI))

			hid->group = HID_GROUP_GENERIC;

		break;

	case HID_GROUP_WACOM:

		if (!IS_ENABLED(CONFIG_HID_WACOM))

			hid->group = HID_GROUP_GENERIC;

		break;

	case HID_GROUP_LOGITECH_DJ_DEVICE:

		if (!IS_ENABLED(CONFIG_HID_LOGITECH_DJ))

			hid->group = HID_GROUP_GENERIC;

		break;

	}

	vfree(parser);

	return 0;

}
@@ -1928,7 +1903,7 @@ static void hid_free_dynids(struct hid_driver *hdrv) 
	spin_unlock(&hdrv->dyn_lock);

}



static const struct hid_device_id *hid_match_device(struct hid_device *hdev,

const struct hid_device_id *hid_match_device(struct hid_device *hdev,

					     struct hid_driver *hdrv)

{

	struct hid_dynid *dynid;
@@ -1944,6 +1919,7 @@ static const struct hid_device_id *hid_match_device(struct hid_device *hdev, 


	return hid_match_id(hdev, hdrv->id_table);

}

EXPORT_SYMBOL_GPL(hid_match_device);



static int hid_bus_match(struct device *dev, struct device_driver *drv)

{
@@ -1973,6 +1949,23 @@ static int hid_device_probe(struct device *dev) 
			goto unlock;

		}



		if (hdrv->match) {

			if (!hdrv->match(hdev, hid_ignore_special_drivers)) {

				ret = -ENODEV;

				goto unlock;

			}

		} else {

			/*

			 * hid-generic implements .match(), so if

			 * hid_ignore_special_drivers is set, we can safely

			 * return.

			 */

			if (hid_ignore_special_drivers) {

				ret = -ENODEV;

				goto unlock;

			}

		}



		hdev->driver = hdrv;

		if (hdrv->probe) {

			ret = hdrv->probe(hdev, id);
@@ -2069,7 +2062,7 @@ static int hid_uevent(struct device *dev, struct kobj_uevent_env *env) 
	return 0;

}



static struct bus_type hid_bus_type = {

struct bus_type hid_bus_type = {

	.name		= "hid",

	.dev_groups	= hid_dev_groups,

	.drv_groups	= hid_drv_groups,
@@ -2203,6 +2196,29 @@ void hid_destroy_device(struct hid_device *hdev) 
}

EXPORT_SYMBOL_GPL(hid_destroy_device);





static int __bus_add_driver(struct device_driver *drv, void *data)

{

	struct hid_driver *added_hdrv = data;

	struct hid_driver *hdrv = to_hid_driver(drv);



	if (hdrv->bus_add_driver)

		hdrv->bus_add_driver(added_hdrv);



	return 0;

}



static int __bus_removed_driver(struct device_driver *drv, void *data)

{

	struct hid_driver *removed_hdrv = data;

	struct hid_driver *hdrv = to_hid_driver(drv);



	if (hdrv->bus_removed_driver)

		hdrv->bus_removed_driver(removed_hdrv);



	return 0;

}



int __hid_register_driver(struct hid_driver *hdrv, struct module *owner,

		const char *mod_name)

{
@@ -2214,6 +2230,8 @@ int __hid_register_driver(struct hid_driver *hdrv, struct module *owner, 
	INIT_LIST_HEAD(&hdrv->dyn_list);

	spin_lock_init(&hdrv->dyn_lock);



	bus_for_each_drv(&hid_bus_type, NULL, hdrv, __bus_add_driver);



	return driver_register(&hdrv->driver);

}

EXPORT_SYMBOL_GPL(__hid_register_driver);
@@ -2222,6 +2240,8 @@ void hid_unregister_driver(struct hid_driver *hdrv) 
{

	driver_unregister(&hdrv->driver);

	hid_free_dynids(hdrv);



	bus_for_each_drv(&hid_bus_type, NULL, hdrv, __bus_removed_driver);

}

EXPORT_SYMBOL_GPL(hid_unregister_driver);

drivers/hid/hid-generic.c

+67 −1
Original line number Diff line number Diff line
@@ -24,8 +24,71 @@ 


#include <linux/hid.h>



static struct hid_driver hid_generic;



static int __unmap_hid_generic(struct device *dev, void *data)

{

	struct hid_driver *hdrv = data;

	struct hid_device *hdev = to_hid_device(dev);



	/* only unbind matching devices already bound to hid-generic */

	if (hdev->driver != &hid_generic ||

	    hid_match_device(hdev, hdrv) == NULL)

		return 0;



	if (dev->parent)	/* Needed for USB */

		device_lock(dev->parent);

	device_release_driver(dev);

	if (dev->parent)

		device_unlock(dev->parent);



	return 0;

}



static void hid_generic_add_driver(struct hid_driver *hdrv)

{

	bus_for_each_dev(&hid_bus_type, NULL, hdrv, __unmap_hid_generic);

}



static void hid_generic_removed_driver(struct hid_driver *hdrv)

{

	int ret;



	ret = driver_attach(&hid_generic.driver);

}



static int __check_hid_generic(struct device_driver *drv, void *data)

{

	struct hid_driver *hdrv = to_hid_driver(drv);

	struct hid_device *hdev = data;



	if (hdrv == &hid_generic)

		return 0;



	return hid_match_device(hdev, hdrv) != NULL;

}



static bool hid_generic_match(struct hid_device *hdev,

			      bool ignore_special_driver)

{

	if (ignore_special_driver)

		return true;



	if (hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)

		return false;



	/*

	 * If any other driver wants the device, leave the device to this other

	 * driver.

	 */

	if (bus_for_each_drv(&hid_bus_type, NULL, hdev, __check_hid_generic))

		return false;



	return true;

}



static const struct hid_device_id hid_table[] = {

	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_GENERIC, HID_ANY_ID, HID_ANY_ID) },

	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY, HID_ANY_ID, HID_ANY_ID) },

	{ }

};

MODULE_DEVICE_TABLE(hid, hid_table);
@@ -33,6 +96,9 @@ MODULE_DEVICE_TABLE(hid, hid_table); 
static struct hid_driver hid_generic = {

	.name = "hid-generic",

	.id_table = hid_table,

	.match = hid_generic_match,

	.bus_add_driver = hid_generic_add_driver,

	.bus_removed_driver = hid_generic_removed_driver,

};

module_hid_driver(hid_generic);

include/linux/hid.h

+10 −0
Original line number Diff line number Diff line
@@ -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);

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