linux/drivers/hid/hid-cypress.c
Frank Yang 652f3d00de HID: cypress: Support Varmilo Keyboards' media hotkeys
The Varmilo VA104M Keyboard (04b4:07b1, reported as Varmilo Z104M)
exposes media control hotkeys as a USB HID consumer control device, but
these keys do not work in the current (5.8-rc1) kernel due to the
incorrect HID report descriptor. Fix the problem by modifying the
internal HID report descriptor.

More specifically, the keyboard report descriptor specifies the
logical boundary as 572~10754 (0x023c ~ 0x2a02) while the usage
boundary is specified as 0~10754 (0x00 ~ 0x2a02). This results in an
incorrect interpretation of input reports, causing inputs to be ignored.
By setting the Logical Minimum to zero, we align the logical boundary
with the Usage ID boundary.

Some notes:

* There seem to be multiple variants of the VA104M keyboard. This
  patch specifically targets 04b4:07b1 variant.

* The device works out-of-the-box on Windows platform with the generic
  consumer control device driver (hidserv.inf). This suggests that
  Windows either ignores the Logical Minimum/Logical Maximum or
  interprets the Usage ID assignment differently from the linux
  implementation; Maybe there are other devices out there that only
  works on Windows due to this problem?

Signed-off-by: Frank Yang <puilp0502@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-10-23 13:23:44 +02:00

180 lines
4.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* HID driver for some cypress "special" devices
*
* 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) 2006-2007 Jiri Kosina
* Copyright (c) 2008 Jiri Slaby
*/
/*
*/
#include <linux/device.h>
#include <linux/hid.h>
#include <linux/input.h>
#include <linux/module.h>
#include "hid-ids.h"
#define CP_RDESC_SWAPPED_MIN_MAX 0x01
#define CP_2WHEEL_MOUSE_HACK 0x02
#define CP_2WHEEL_MOUSE_HACK_ON 0x04
#define VA_INVAL_LOGICAL_BOUNDARY 0x08
/*
* Some USB barcode readers from cypress have usage min and usage max in
* the wrong order
*/
static __u8 *cp_rdesc_fixup(struct hid_device *hdev, __u8 *rdesc,
unsigned int *rsize)
{
unsigned int i;
if (*rsize < 4)
return rdesc;
for (i = 0; i < *rsize - 4; i++)
if (rdesc[i] == 0x29 && rdesc[i + 2] == 0x19) {
rdesc[i] = 0x19;
rdesc[i + 2] = 0x29;
swap(rdesc[i + 3], rdesc[i + 1]);
}
return rdesc;
}
static __u8 *va_logical_boundary_fixup(struct hid_device *hdev, __u8 *rdesc,
unsigned int *rsize)
{
/*
* Varmilo VA104M (with VID Cypress and device ID 07B1) incorrectly
* reports Logical Minimum of its Consumer Control device as 572
* (0x02 0x3c). Fix this by setting its Logical Minimum to zero.
*/
if (*rsize == 25 &&
rdesc[0] == 0x05 && rdesc[1] == 0x0c &&
rdesc[2] == 0x09 && rdesc[3] == 0x01 &&
rdesc[6] == 0x19 && rdesc[7] == 0x00 &&
rdesc[11] == 0x16 && rdesc[12] == 0x3c && rdesc[13] == 0x02) {
hid_info(hdev,
"fixing up varmilo VA104M consumer control report descriptor\n");
rdesc[12] = 0x00;
rdesc[13] = 0x00;
}
return rdesc;
}
static __u8 *cp_report_fixup(struct hid_device *hdev, __u8 *rdesc,
unsigned int *rsize)
{
unsigned long quirks = (unsigned long)hid_get_drvdata(hdev);
if (quirks & CP_RDESC_SWAPPED_MIN_MAX)
rdesc = cp_rdesc_fixup(hdev, rdesc, rsize);
if (quirks & VA_INVAL_LOGICAL_BOUNDARY)
rdesc = va_logical_boundary_fixup(hdev, rdesc, rsize);
return rdesc;
}
static int cp_input_mapped(struct hid_device *hdev, struct hid_input *hi,
struct hid_field *field, struct hid_usage *usage,
unsigned long **bit, int *max)
{
unsigned long quirks = (unsigned long)hid_get_drvdata(hdev);
if (!(quirks & CP_2WHEEL_MOUSE_HACK))
return 0;
if (usage->type == EV_REL && usage->code == REL_WHEEL)
set_bit(REL_HWHEEL, *bit);
if (usage->hid == 0x00090005)
return -1;
return 0;
}
static int cp_event(struct hid_device *hdev, struct hid_field *field,
struct hid_usage *usage, __s32 value)
{
unsigned long quirks = (unsigned long)hid_get_drvdata(hdev);
if (!(hdev->claimed & HID_CLAIMED_INPUT) || !field->hidinput ||
!usage->type || !(quirks & CP_2WHEEL_MOUSE_HACK))
return 0;
if (usage->hid == 0x00090005) {
if (value)
quirks |= CP_2WHEEL_MOUSE_HACK_ON;
else
quirks &= ~CP_2WHEEL_MOUSE_HACK_ON;
hid_set_drvdata(hdev, (void *)quirks);
return 1;
}
if (usage->code == REL_WHEEL && (quirks & CP_2WHEEL_MOUSE_HACK_ON)) {
struct input_dev *input = field->hidinput->input;
input_event(input, usage->type, REL_HWHEEL, value);
return 1;
}
return 0;
}
static int cp_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
unsigned long quirks = id->driver_data;
int ret;
hid_set_drvdata(hdev, (void *)quirks);
ret = hid_parse(hdev);
if (ret) {
hid_err(hdev, "parse failed\n");
goto err_free;
}
ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
if (ret) {
hid_err(hdev, "hw start failed\n");
goto err_free;
}
return 0;
err_free:
return ret;
}
static const struct hid_device_id cp_devices[] = {
{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_1),
.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_2),
.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_3),
.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_4),
.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_MOUSE),
.driver_data = CP_2WHEEL_MOUSE_HACK },
{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_VARMILO_VA104M_07B1),
.driver_data = VA_INVAL_LOGICAL_BOUNDARY },
{ }
};
MODULE_DEVICE_TABLE(hid, cp_devices);
static struct hid_driver cp_driver = {
.name = "cypress",
.id_table = cp_devices,
.report_fixup = cp_report_fixup,
.input_mapped = cp_input_mapped,
.event = cp_event,
.probe = cp_probe,
};
module_hid_driver(cp_driver);
MODULE_LICENSE("GPL");