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Input: wacom - use full 32-bit HID Usage value in switch statement
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A HID Usage is a 32-bit value: an upper 16-bit "page" and a lower 16-bit
ID. While the two halves are normally reported seperately, only the
combination uniquely idenfifes a particular HID Usage.

The existing code performs the comparison in two steps, first performing a
switch on the ID and then verifying the page within each case. While this
works fine, it is very akward to handle two Usages that share a single ID,
such as HID_USAGE_PRESSURE and HID_USAGE_X because the case statement can
only have a single identifier.

To work around this, we now check the full 32-bit HID Usage directly rather
than first checking the ID and then the page.  This allows the switch
statement to have distinct cases for e.g. HID_USAGE_PRESSURE and
HID_USAGE_X.

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Tested-by: Aaron Skomra <Aaron.Skomra@wacom.com>
Reviewed-by: Carl Worth <cworth@cworth.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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Jason Gerecke authored and Dmitry Torokhov committed Apr 19, 2014
1 parent 91ae0e7 commit 5866d9e
Showing 1 changed file with 109 additions and 128 deletions.
237 changes: 109 additions & 128 deletions drivers/input/tablet/wacom_sys.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,23 +22,17 @@
#define HID_USAGE_PAGE_DIGITIZER 0x0d
#define HID_USAGE_PAGE_DESKTOP 0x01
#define HID_USAGE 0x09
#define HID_USAGE_X 0x30
#define HID_USAGE_Y 0x31
#define HID_USAGE_X_TILT 0x3d
#define HID_USAGE_Y_TILT 0x3e
#define HID_USAGE_FINGER 0x22
#define HID_USAGE_STYLUS 0x20
#define HID_USAGE_CONTACTMAX 0x55
#define HID_USAGE_X ((HID_USAGE_PAGE_DESKTOP << 16) | 0x30)
#define HID_USAGE_Y ((HID_USAGE_PAGE_DESKTOP << 16) | 0x31)
#define HID_USAGE_X_TILT ((HID_USAGE_PAGE_DIGITIZER << 16) | 0x3d)
#define HID_USAGE_Y_TILT ((HID_USAGE_PAGE_DIGITIZER << 16) | 0x3e)
#define HID_USAGE_FINGER ((HID_USAGE_PAGE_DIGITIZER << 16) | 0x22)
#define HID_USAGE_STYLUS ((HID_USAGE_PAGE_DIGITIZER << 16) | 0x20)
#define HID_USAGE_CONTACTMAX ((HID_USAGE_PAGE_DIGITIZER << 16) | 0x55)
#define HID_COLLECTION 0xa1
#define HID_COLLECTION_LOGICAL 0x02
#define HID_COLLECTION_END 0xc0

enum {
WCM_UNDEFINED = 0,
WCM_DESKTOP,
WCM_DIGITIZER,
};

struct hid_descriptor {
struct usb_descriptor_header header;
__le16 bcdHID;
Expand Down Expand Up @@ -305,7 +299,7 @@ static int wacom_parse_hid(struct usb_interface *intf,
char limit = 0;
/* result has to be defined as int for some devices */
int result = 0, touch_max = 0;
int i = 0, usage = WCM_UNDEFINED, finger = 0, pen = 0;
int i = 0, page = 0, finger = 0, pen = 0;
unsigned char *report;

report = kzalloc(hid_desc->wDescriptorLength, GFP_KERNEL);
Expand All @@ -332,134 +326,121 @@ static int wacom_parse_hid(struct usb_interface *intf,

switch (report[i]) {
case HID_USAGE_PAGE:
switch (report[i + 1]) {
case HID_USAGE_PAGE_DIGITIZER:
usage = WCM_DIGITIZER;
i++;
break;

case HID_USAGE_PAGE_DESKTOP:
usage = WCM_DESKTOP;
i++;
break;
}
page = report[i + 1];
i++;
break;

case HID_USAGE:
switch (report[i + 1]) {
switch (page << 16 | report[i + 1]) {
case HID_USAGE_X:
if (usage == WCM_DESKTOP) {
if (finger) {
features->device_type = BTN_TOOL_FINGER;
/* touch device at least supports one touch point */
touch_max = 1;
switch (features->type) {
case TABLETPC2FG:
features->pktlen = WACOM_PKGLEN_TPC2FG;
break;

case MTSCREEN:
case WACOM_24HDT:
features->pktlen = WACOM_PKGLEN_MTOUCH;
break;

case MTTPC:
features->pktlen = WACOM_PKGLEN_MTTPC;
break;

case BAMBOO_PT:
features->pktlen = WACOM_PKGLEN_BBTOUCH;
break;

default:
features->pktlen = WACOM_PKGLEN_GRAPHIRE;
break;
}

switch (features->type) {
case BAMBOO_PT:
features->x_phy =
get_unaligned_le16(&report[i + 5]);
features->x_max =
get_unaligned_le16(&report[i + 8]);
i += 15;
break;

case WACOM_24HDT:
features->x_max =
get_unaligned_le16(&report[i + 3]);
features->x_phy =
get_unaligned_le16(&report[i + 8]);
features->unit = report[i - 1];
features->unitExpo = report[i - 3];
i += 12;
break;

default:
features->x_max =
get_unaligned_le16(&report[i + 3]);
features->x_phy =
get_unaligned_le16(&report[i + 6]);
features->unit = report[i + 9];
features->unitExpo = report[i + 11];
i += 12;
break;
}
} else if (pen) {
/* penabled only accepts exact bytes of data */
if (features->type >= TABLETPC)
features->pktlen = WACOM_PKGLEN_GRAPHIRE;
features->device_type = BTN_TOOL_PEN;
if (finger) {
features->device_type = BTN_TOOL_FINGER;
/* touch device at least supports one touch point */
touch_max = 1;
switch (features->type) {
case TABLETPC2FG:
features->pktlen = WACOM_PKGLEN_TPC2FG;
break;

case MTSCREEN:
case WACOM_24HDT:
features->pktlen = WACOM_PKGLEN_MTOUCH;
break;

case MTTPC:
features->pktlen = WACOM_PKGLEN_MTTPC;
break;

case BAMBOO_PT:
features->pktlen = WACOM_PKGLEN_BBTOUCH;
break;

default:
features->pktlen = WACOM_PKGLEN_GRAPHIRE;
break;
}

switch (features->type) {
case BAMBOO_PT:
features->x_phy =
get_unaligned_le16(&report[i + 5]);
features->x_max =
get_unaligned_le16(&report[i + 8]);
i += 15;
break;

case WACOM_24HDT:
features->x_max =
get_unaligned_le16(&report[i + 3]);
i += 4;
features->x_phy =
get_unaligned_le16(&report[i + 8]);
features->unit = report[i - 1];
features->unitExpo = report[i - 3];
i += 12;
break;

default:
features->x_max =
get_unaligned_le16(&report[i + 3]);
features->x_phy =
get_unaligned_le16(&report[i + 6]);
features->unit = report[i + 9];
features->unitExpo = report[i + 11];
i += 12;
break;
}
} else if (pen) {
/* penabled only accepts exact bytes of data */
if (features->type >= TABLETPC)
features->pktlen = WACOM_PKGLEN_GRAPHIRE;
features->device_type = BTN_TOOL_PEN;
features->x_max =
get_unaligned_le16(&report[i + 3]);
i += 4;
}
break;

case HID_USAGE_Y:
if (usage == WCM_DESKTOP) {
if (finger) {
switch (features->type) {
case TABLETPC2FG:
case MTSCREEN:
case MTTPC:
features->y_max =
get_unaligned_le16(&report[i + 3]);
features->y_phy =
get_unaligned_le16(&report[i + 6]);
i += 7;
break;

case WACOM_24HDT:
features->y_max =
get_unaligned_le16(&report[i + 3]);
features->y_phy =
get_unaligned_le16(&report[i - 2]);
i += 7;
break;

case BAMBOO_PT:
features->y_phy =
get_unaligned_le16(&report[i + 3]);
features->y_max =
get_unaligned_le16(&report[i + 6]);
i += 12;
break;

default:
features->y_max =
features->x_max;
features->y_phy =
get_unaligned_le16(&report[i + 3]);
i += 4;
break;
}
} else if (pen) {
if (finger) {
switch (features->type) {
case TABLETPC2FG:
case MTSCREEN:
case MTTPC:
features->y_max =
get_unaligned_le16(&report[i + 3]);
features->y_phy =
get_unaligned_le16(&report[i + 6]);
i += 7;
break;

case WACOM_24HDT:
features->y_max =
get_unaligned_le16(&report[i + 3]);
features->y_phy =
get_unaligned_le16(&report[i - 2]);
i += 7;
break;

case BAMBOO_PT:
features->y_phy =
get_unaligned_le16(&report[i + 3]);
features->y_max =
get_unaligned_le16(&report[i + 6]);
i += 12;
break;

default:
features->y_max =
features->x_max;
features->y_phy =
get_unaligned_le16(&report[i + 3]);
i += 4;
break;
}
} else if (pen) {
features->y_max =
get_unaligned_le16(&report[i + 3]);
i += 4;
}
break;

Expand Down Expand Up @@ -489,7 +470,7 @@ static int wacom_parse_hid(struct usb_interface *intf,

case HID_COLLECTION_END:
/* reset UsagePage and Finger */
finger = usage = 0;
finger = page = 0;
break;

case HID_COLLECTION:
Expand Down

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