HID: wacom: Clean up value reading

Make the logic for reading X, Y, distance, and pressure a bit more
clear. An additional bit was stuffed into the packet format many
models back, and /most/ devices in use will use it. If we happen
to be dealing with a particularly old tablet, just shift it off
the end to pretend we never read it.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index ce3afab..0008650 100644 (file)
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -887,21 +887,23 @@ static int wacom_intuos_general(struct wacom_wac *wacom)
        struct input_dev *input = wacom->pen_input;
        int idx = (features->type == INTUOS) ? (data[1] & 0x01) : 0;
        unsigned char type = (data[1] >> 1) & 0x0F;
-       unsigned int t;
+       unsigned int x, y, distance, t;
 
        if (data[0] != WACOM_REPORT_PENABLED && data[0] != WACOM_REPORT_CINTIQ &&
                data[0] != WACOM_REPORT_INTUOS_PEN)
                return 0;
 
-       if (features->type >= INTUOS3S) {
-               input_report_abs(input, ABS_X, (data[2] << 9) | (data[3] << 1) | ((data[9] >> 1) & 1));
-               input_report_abs(input, ABS_Y, (data[4] << 9) | (data[5] << 1) | (data[9] & 1));
-               input_report_abs(input, ABS_DISTANCE, ((data[9] >> 2) & 0x3f));
-       } else {
-               input_report_abs(input, ABS_X, be16_to_cpup((__be16 *)&data[2]));
-               input_report_abs(input, ABS_Y, be16_to_cpup((__be16 *)&data[4]));
-               input_report_abs(input, ABS_DISTANCE, ((data[9] >> 3) & 0x1f));
+       x = (be16_to_cpup((__be16 *)&data[2]) << 1) | ((data[9] >> 1) & 1);
+       y = (be16_to_cpup((__be16 *)&data[4]) << 1) | (data[9] & 1);
+       distance = data[9] >> 2;
+       if (features->type < INTUOS3S) {
+               x >>= 1;
+               y >>= 1;
+               distance >>= 1;
        }
+       input_report_abs(input, ABS_X, x);
+       input_report_abs(input, ABS_Y, y);
+       input_report_abs(input, ABS_DISTANCE, distance);
 
        switch (type) {
        case 0x00:
@@ -909,10 +911,9 @@ static int wacom_intuos_general(struct wacom_wac *wacom)
        case 0x02:
        case 0x03:
                /* general pen packet */
-               t = (data[6] << 2) | ((data[7] >> 6) & 3);
-               if (features->pressure_max == 2047) {
-                       t = (t << 1) | (data[1] & 1);
-               }
+               t = (data[6] << 3) | ((data[7] & 0xC0) >> 5) | (data[1] & 1);
+               if (features->pressure_max < 2047)
+                       t >>= 1;
                input_report_abs(input, ABS_PRESSURE, t);
                if (features->type != INTUOSHT2) {
                    input_report_abs(input, ABS_TILT_X,