linux/drivers/hid/hid-generic.c
Benjamin Tissoires e04a0442d3 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>
2017-11-21 11:14:48 +01:00

108 lines
2.6 KiB
C

/*
* HID support for Linux
*
* Copyright (c) 1999 Andreas Gal
* Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
* Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
* Copyright (c) 2007-2008 Oliver Neukum
* Copyright (c) 2006-2012 Jiri Kosina
* Copyright (c) 2012 Henrik Rydberg
*/
/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <asm/unaligned.h>
#include <asm/byteorder.h>
#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_ANY, HID_ANY_ID, HID_ANY_ID) },
{ }
};
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);
MODULE_AUTHOR("Henrik Rydberg");
MODULE_DESCRIPTION("HID generic driver");
MODULE_LICENSE("GPL");