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HID: huion: Switch to generating report descriptor
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Switch to generating tablet pen report descriptor from a template and
parameters retrieved from string descriptor 0x64.

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Nikolai Kondrashov authored and Jiri Kosina committed Jul 29, 2014
1 parent fb85329 commit f8dd5cb
Showing 1 changed file with 167 additions and 78 deletions.
245 changes: 167 additions & 78 deletions drivers/hid/hid-huion.c
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Original file line number Diff line number Diff line change
@@ -16,125 +16,214 @@
#include <linux/hid.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <asm/unaligned.h>
#include "usbhid/usbhid.h"

#include "hid-ids.h"

/* Original tablet report descriptor size */
#define HUION_TABLET_RDESC_ORIG_SIZE 177

/* Fixed tablet report descriptor */
static __u8 huion_tablet_rdesc_fixed[] = {
0x05, 0x0D, /* Usage Page (Digitizer), */
0x09, 0x02, /* Usage (Pen), */
0xA1, 0x01, /* Collection (Application), */
0x85, 0x07, /* Report ID (7), */
0x09, 0x20, /* Usage (Stylus), */
0xA0, /* Collection (Physical), */
0x14, /* Logical Minimum (0), */
0x25, 0x01, /* Logical Maximum (1), */
0x75, 0x01, /* Report Size (1), */
0x09, 0x42, /* Usage (Tip Switch), */
0x09, 0x44, /* Usage (Barrel Switch), */
0x09, 0x46, /* Usage (Tablet Pick), */
0x95, 0x03, /* Report Count (3), */
0x81, 0x02, /* Input (Variable), */
0x95, 0x03, /* Report Count (3), */
0x81, 0x03, /* Input (Constant, Variable), */
0x09, 0x32, /* Usage (In Range), */
0x95, 0x01, /* Report Count (1), */
0x81, 0x02, /* Input (Variable), */
0x95, 0x01, /* Report Count (1), */
0x81, 0x03, /* Input (Constant, Variable), */
0x75, 0x10, /* Report Size (16), */
0x95, 0x01, /* Report Count (1), */
0xA4, /* Push, */
0x05, 0x01, /* Usage Page (Desktop), */
0x65, 0x13, /* Unit (Inch), */
0x55, 0xFD, /* Unit Exponent (-3), */
0x34, /* Physical Minimum (0), */
0x09, 0x30, /* Usage (X), */
0x46, 0x40, 0x1F, /* Physical Maximum (8000), */
0x26, 0x00, 0x7D, /* Logical Maximum (32000), */
0x81, 0x02, /* Input (Variable), */
0x09, 0x31, /* Usage (Y), */
0x46, 0x88, 0x13, /* Physical Maximum (5000), */
0x26, 0x20, 0x4E, /* Logical Maximum (20000), */
0x81, 0x02, /* Input (Variable), */
0xB4, /* Pop, */
0x09, 0x30, /* Usage (Tip Pressure), */
0x26, 0xFF, 0x07, /* Logical Maximum (2047), */
0x81, 0x02, /* Input (Variable), */
0xC0, /* End Collection, */
0xC0 /* End Collection */
/* Report descriptor template placeholder head */
#define HUION_PH_HEAD 0xFE, 0xED, 0x1D

/* Report descriptor template placeholder IDs */
enum huion_ph_id {
HUION_PH_ID_X_LM,
HUION_PH_ID_X_PM,
HUION_PH_ID_Y_LM,
HUION_PH_ID_Y_PM,
HUION_PH_ID_PRESSURE_LM,
HUION_PH_ID_NUM
};

/* Report descriptor template placeholder */
#define HUION_PH(_ID) HUION_PH_HEAD, HUION_PH_ID_##_ID

/* Fixed report descriptor template */
static const __u8 huion_tablet_rdesc_template[] = {
0x05, 0x0D, /* Usage Page (Digitizer), */
0x09, 0x02, /* Usage (Pen), */
0xA1, 0x01, /* Collection (Application), */
0x85, 0x07, /* Report ID (7), */
0x09, 0x20, /* Usage (Stylus), */
0xA0, /* Collection (Physical), */
0x14, /* Logical Minimum (0), */
0x25, 0x01, /* Logical Maximum (1), */
0x75, 0x01, /* Report Size (1), */
0x09, 0x42, /* Usage (Tip Switch), */
0x09, 0x44, /* Usage (Barrel Switch), */
0x09, 0x46, /* Usage (Tablet Pick), */
0x95, 0x03, /* Report Count (3), */
0x81, 0x02, /* Input (Variable), */
0x95, 0x03, /* Report Count (3), */
0x81, 0x03, /* Input (Constant, Variable), */
0x09, 0x32, /* Usage (In Range), */
0x95, 0x01, /* Report Count (1), */
0x81, 0x02, /* Input (Variable), */
0x95, 0x01, /* Report Count (1), */
0x81, 0x03, /* Input (Constant, Variable), */
0x75, 0x10, /* Report Size (16), */
0x95, 0x01, /* Report Count (1), */
0xA4, /* Push, */
0x05, 0x01, /* Usage Page (Desktop), */
0x65, 0x13, /* Unit (Inch), */
0x55, 0xFD, /* Unit Exponent (-3), */
0x34, /* Physical Minimum (0), */
0x09, 0x30, /* Usage (X), */
0x27, HUION_PH(X_LM), /* Logical Maximum (PLACEHOLDER), */
0x47, HUION_PH(X_PM), /* Physical Maximum (PLACEHOLDER), */
0x81, 0x02, /* Input (Variable), */
0x09, 0x31, /* Usage (Y), */
0x27, HUION_PH(Y_LM), /* Logical Maximum (PLACEHOLDER), */
0x47, HUION_PH(Y_PM), /* Physical Maximum (PLACEHOLDER), */
0x81, 0x02, /* Input (Variable), */
0xB4, /* Pop, */
0x09, 0x30, /* Usage (Tip Pressure), */
0x27,
HUION_PH(PRESSURE_LM), /* Logical Maximum (PLACEHOLDER), */
0x81, 0x02, /* Input (Variable), */
0xC0, /* End Collection, */
0xC0 /* End Collection */
};

/* Driver data */
struct huion_drvdata {
__u8 *rdesc;
unsigned int rsize;
};

static __u8 *huion_report_fixup(struct hid_device *hdev, __u8 *rdesc,
unsigned int *rsize)
{
struct huion_drvdata *drvdata = hid_get_drvdata(hdev);
switch (hdev->product) {
case USB_DEVICE_ID_HUION_TABLET:
if (*rsize == HUION_TABLET_RDESC_ORIG_SIZE) {
rdesc = huion_tablet_rdesc_fixed;
*rsize = sizeof(huion_tablet_rdesc_fixed);
if (drvdata->rdesc != NULL) {
rdesc = drvdata->rdesc;
*rsize = drvdata->rsize;
}
break;
}
return rdesc;
}

/**
* Enable fully-functional tablet mode by reading special string
* descriptor.
* Enable fully-functional tablet mode and determine device parameters.
*
* @hdev: HID device
*
* The specific string descriptor and data were discovered by sniffing
* the Windows driver traffic.
*/
static int huion_tablet_enable(struct hid_device *hdev)
{
int rc;
char buf[22];
struct usb_device *usb_dev = hid_to_usb_dev(hdev);
struct huion_drvdata *drvdata = hid_get_drvdata(hdev);
u16 buf[6];

rc = usb_string(hid_to_usb_dev(hdev), 0x64, buf, sizeof(buf));
if (rc < 0)
return rc;
/*
* Read string descriptor containing tablet parameters. The specific
* string descriptor and data were discovered by sniffing the Windows
* driver traffic.
* NOTE: This enables fully-functional tablet mode.
*/
rc = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
(USB_DT_STRING << 8) + 0x64,
0x0409, buf, sizeof(buf),
USB_CTRL_GET_TIMEOUT);
if (rc == -EPIPE)
hid_warn(hdev, "device parameters not found\n");
else if (rc < 0)
hid_warn(hdev, "failed to get device parameters: %d\n", rc);
else if (rc != sizeof(buf))
hid_warn(hdev, "invalid device parameters\n");
else {
s32 params[HUION_PH_ID_NUM];
s32 resolution;
__u8 *p;
s32 v;

/* Extract device parameters */
params[HUION_PH_ID_X_LM] = le16_to_cpu(buf[1]);
params[HUION_PH_ID_Y_LM] = le16_to_cpu(buf[2]);
params[HUION_PH_ID_PRESSURE_LM] = le16_to_cpu(buf[4]);
resolution = le16_to_cpu(buf[5]);
if (resolution == 0) {
params[HUION_PH_ID_X_PM] = 0;
params[HUION_PH_ID_Y_PM] = 0;
} else {
params[HUION_PH_ID_X_PM] = params[HUION_PH_ID_X_LM] *
1000 / resolution;
params[HUION_PH_ID_Y_PM] = params[HUION_PH_ID_Y_LM] *
1000 / resolution;
}

/* Allocate fixed report descriptor */
drvdata->rdesc = devm_kmalloc(&hdev->dev,
sizeof(huion_tablet_rdesc_template),
GFP_KERNEL);
if (drvdata->rdesc == NULL) {
hid_err(hdev, "failed to allocate fixed rdesc\n");
return -ENOMEM;
}
drvdata->rsize = sizeof(huion_tablet_rdesc_template);

/* Format fixed report descriptor */
memcpy(drvdata->rdesc, huion_tablet_rdesc_template,
drvdata->rsize);
for (p = drvdata->rdesc;
p <= drvdata->rdesc + drvdata->rsize - 4;) {
if (p[0] == 0xFE && p[1] == 0xED && p[2] == 0x1D &&
p[3] < sizeof(params)) {
v = params[p[3]];
put_unaligned(cpu_to_le32(v), (s32 *)p);
p += 4;
} else {
p++;
}
}
}

return 0;
}

static int huion_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
int ret;

ret = hid_parse(hdev);
if (ret) {
hid_err(hdev, "parse failed\n");
goto err;
}
int rc;
struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
struct huion_drvdata *drvdata;

ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
if (ret) {
hid_err(hdev, "hw start failed\n");
goto err;
/* Allocate and assign driver data */
drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
if (drvdata == NULL) {
hid_err(hdev, "failed to allocate driver data\n");
return -ENOMEM;
}
hid_set_drvdata(hdev, drvdata);

switch (id->product) {
case USB_DEVICE_ID_HUION_TABLET:
ret = huion_tablet_enable(hdev);
if (ret) {
hid_err(hdev, "tablet enabling failed\n");
goto enabling_err;
/* If this is the pen interface */
if (intf->cur_altsetting->desc.bInterfaceNumber == 0) {
rc = huion_tablet_enable(hdev);
if (rc) {
hid_err(hdev, "tablet enabling failed\n");
return rc;
}
}
break;
}

rc = hid_parse(hdev);
if (rc) {
hid_err(hdev, "parse failed\n");
return rc;
}

rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
if (rc) {
hid_err(hdev, "hw start failed\n");
return rc;
}

return 0;
enabling_err:
hid_hw_stop(hdev);
err:
return ret;
}

static int huion_raw_event(struct hid_device *hdev, struct hid_report *report,

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