linux/drivers/hid/hid-elecom.c
Tomasz Kramkowski ac58eec2c5 HID: elecom: rewrite report fixup for EX-G and future mice
This patch rewrites the mouse report fixup used for the DEFT and HUGE
elecom trackballs in order to make it generic enough to fix other
elecom mice with similar issues. This patch also uses this new report
fixup function to fix the Elecom EX-G trackball which has 6 physical
buttons and a similar issue to the other two mice.

Elecom's track record has so far shown that they like to re-use the
same report descriptor for multiple different mice regardless of the
number of buttons the mouse has. This means that the missing buttons
on multiple mice can be fixed in one function without introducing
phantom buttons which would in turn cause the number of mouse buttons
to be misreported to userspace.

This patch drops the very verbose report descriptor "diff" comment for
a more abridged yet hopefully just as informative generic version.

Signed-off-by: Tomasz Kramkowski <tk@the-tk.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2018-01-23 15:39:54 +01:00

102 lines
3.5 KiB
C

/*
* HID driver for ELECOM devices:
* - BM084 Bluetooth Mouse
* - EX-G Trackball (Wired and wireless)
* - DEFT Trackball (Wired and wireless)
* - HUGE Trackball (Wired and wireless)
*
* Copyright (c) 2010 Richard Nauber <Richard.Nauber@gmail.com>
* Copyright (c) 2016 Yuxuan Shui <yshuiv7@gmail.com>
* Copyright (c) 2017 Diego Elio Pettenò <flameeyes@flameeyes.eu>
* Copyright (c) 2017 Alex Manoussakis <amanou@gnu.org>
* Copyright (c) 2017 Tomasz Kramkowski <tk@the-tk.com>
*/
/*
* 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/device.h>
#include <linux/hid.h>
#include <linux/module.h>
#include "hid-ids.h"
/*
* Certain ELECOM mice misreport their button count meaning that they only work
* correctly with the ELECOM mouse assistant software which is unavailable for
* Linux. A four extra INPUT reports and a FEATURE report are described by the
* report descriptor but it does not appear that these enable software to
* control what the extra buttons map to. The only simple and straightforward
* solution seems to involve fixing up the report descriptor.
*
* Report descriptor format:
* Positions 13, 15, 21 and 31 store the button bit count, button usage minimum,
* button usage maximum and padding bit count respectively.
*/
#define MOUSE_BUTTONS_MAX 8
static void mouse_button_fixup(struct hid_device *hdev,
__u8 *rdesc, unsigned int rsize,
int nbuttons)
{
if (rsize < 32 || rdesc[12] != 0x95 ||
rdesc[14] != 0x75 || rdesc[15] != 0x01 ||
rdesc[20] != 0x29 || rdesc[30] != 0x75)
return;
hid_info(hdev, "Fixing up Elecom mouse button count\n");
nbuttons = clamp(nbuttons, 0, MOUSE_BUTTONS_MAX);
rdesc[13] = nbuttons;
rdesc[21] = nbuttons;
rdesc[31] = MOUSE_BUTTONS_MAX - nbuttons;
}
static __u8 *elecom_report_fixup(struct hid_device *hdev, __u8 *rdesc,
unsigned int *rsize)
{
switch (hdev->product) {
case USB_DEVICE_ID_ELECOM_BM084:
/* The BM084 Bluetooth mouse includes a non-existing horizontal
* wheel in the HID descriptor. */
if (*rsize >= 48 && rdesc[46] == 0x05 && rdesc[47] == 0x0c) {
hid_info(hdev, "Fixing up Elecom BM084 report descriptor\n");
rdesc[47] = 0x00;
}
break;
case USB_DEVICE_ID_ELECOM_EX_G_WIRED:
case USB_DEVICE_ID_ELECOM_EX_G_WIRELESS:
mouse_button_fixup(hdev, rdesc, *rsize, 6);
break;
case USB_DEVICE_ID_ELECOM_DEFT_WIRED:
case USB_DEVICE_ID_ELECOM_DEFT_WIRELESS:
case USB_DEVICE_ID_ELECOM_HUGE_WIRED:
case USB_DEVICE_ID_ELECOM_HUGE_WIRELESS:
mouse_button_fixup(hdev, rdesc, *rsize, 8);
break;
}
return rdesc;
}
static const struct hid_device_id elecom_devices[] = {
{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_BM084) },
{ HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_EX_G_WIRED) },
{ HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_EX_G_WIRELESS) },
{ HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_DEFT_WIRED) },
{ HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_DEFT_WIRELESS) },
{ HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_HUGE_WIRED) },
{ HID_USB_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_HUGE_WIRELESS) },
{ }
};
MODULE_DEVICE_TABLE(hid, elecom_devices);
static struct hid_driver elecom_driver = {
.name = "elecom",
.id_table = elecom_devices,
.report_fixup = elecom_report_fixup
};
module_hid_driver(elecom_driver);
MODULE_LICENSE("GPL");