Input: wacom - fix touch parsing on newer Bamboos

Bamboos with Product ID's > 0xD4 return values unrelated to pressure
in touch 1 pressure field.  They also report 2nd touch X/Y values
shifted down 1 byte (where pressure was).  This results in jumpy
1 finger touch and totally invalid 2nd finger data.

For touch detection, switch to a Touch Present single bit that
all versions of Bamboo support.

For touch 2 offset, calculate offset based on a bit that is set
different between the two packet layouts.

Since touch pressure reports were removed from driver, there was
no need to be reading pressure any more.

Signed-off-by: Chris Bagwell <chris@cnpbagwell.com>
Reviewed-by: Ping Cheng <pinglinux@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 8 insertions, 6 deletions

diff --git a/drivers/input/tablet/wacom_wac.c b/drivers/input/tablet/wacom_wac.c
index c31e4e9f2690..0dc97ec15c28 100644
--- a/drivers/input/tablet/wacom_wac.c
+++ b/drivers/input/tablet/wacom_wac.c
@@ -800,20 +800,22 @@ static int wacom_bpt_touch(struct wacom_wac *wacom)
         int i;
 
         for (i = 0; i < 2; i++) {
-                int p = data[9 * i + 2];
-                bool touch = p && !wacom->shared->stylus_in_proximity;
+                int offset = (data[1] & 0x80) ? (8 * i) : (9 * i);
+                bool touch = data[offset + 3] & 0x80;
 
-                input_mt_slot(input, i);
-                input_mt_report_slot_state(input, MT_TOOL_FINGER, touch);
                 /*
                  * Touch events need to be disabled while stylus is
                  * in proximity because user's hand is resting on touchpad
                  * and sending unwanted events.  User expects tablet buttons
                  * to continue working though.
                  */
+                touch = touch && !wacom->shared->stylus_in_proximity;
+
+                input_mt_slot(input, i);
+                input_mt_report_slot_state(input, MT_TOOL_FINGER, touch);
                 if (touch) {
-                        int x = get_unaligned_be16(&data[9 * i + 3]) & 0x7ff;
-                        int y = get_unaligned_be16(&data[9 * i + 5]) & 0x7ff;
+                        int x = get_unaligned_be16(&data[offset + 3]) & 0x7ff;
+                        int y = get_unaligned_be16(&data[offset + 5]) & 0x7ff;
                         if (features->quirks & WACOM_QUIRK_BBTOUCH_LOWRES) {
                                 x <<= 5;
                                 y <<= 5;