Input: wacom - use full 32-bit HID Usage value in switch statement

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>

diff --git a/drivers/input/tablet/wacom_sys.c b/drivers/input/tablet/wacom_sys.c
index b16ebef..5be6177 100644 (file)
--- a/drivers/input/tablet/wacom_sys.c
+++ b/drivers/input/tablet/wacom_sys.c
@@ -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;
@@ -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);
@@ -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;
 
@@ -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: