HID: Add device group to modalias

HID devices are only partially presented to userland.  Hotplugged
devices emit events containing a modalias based on the basic bus,
vendor and product entities. However, in practise a hid device can
depend on details such as a single usb interface or a particular item
in a report descriptor.

This patch adds a device group to the hid device id, and broadcasts it
using uevent and the device modalias.  The module alias generation is
modified to match. As a consequence, a device with a non-zero group
will be processed by the corresponding group driver instead of by the
generic hid driver.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Acked-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/hid.h b/include/linux/hid.h
index d8e7cc7f894f..a0e27ddb887d 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -476,6 +476,7 @@ struct hid_device {							/* device report descriptor */
         unsigned maxcollection;                                         /* Number of parsed collections */
         unsigned maxapplication;                                        /* Number of applications */
         __u16 bus;                                                      /* BUS ID */
+        __u16 group;                                                    /* Report group */
         __u32 vendor;                                                   /* Vendor ID */
         __u32 product;                                                  /* Product ID */
         __u32 version;                                                  /* HID version */
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 501da4cb8a6d..55ed0b0dc610 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -132,10 +132,11 @@ struct usb_device_id {
 #define USB_DEVICE_ID_MATCH_INT_PROTOCOL        0x0200
 
 #define HID_ANY_ID                              (~0)
+#define HID_GROUP_ANY                           0x0000
 
 struct hid_device_id {
         __u16 bus;
-        __u16 pad1;
+        __u16 group;
         __u32 vendor;
         __u32 product;
         kernel_ulong_t driver_data