HID: Fix for problems with eGalax/DWAV multi-touch-screen

This patch fixes three problems with the eGalax/DWAV multi-touch
screen found in the Eee PC T101MT:

1) While there is a dedicated multitouch driver for the screen
   (hid-egalax.c), the MULTI_INPUT quirk is also applied, preventing
   the hid-egalax driver from working. This patch removes the quirk
   so the hid-egalax driver can handle the device correctly.
2) The x and y coordinates sent by the screen in multi-touch mode are
   shifted by three bits from the events sent in single-touch mode, thus
   the coordinates are out of range, leading to the pointer being stuck
   in the bottom-right corner if no additional calibration is applied
   (e.g. in the X evdev driver). This patch shifts the coordinates back.
   This does not decrease accuracy as the last three bits of the "wrong"
   coordinates are always 0.
3) Only multi-touch pressure events are sent, single touch emulation is
   missing pressure information. This patch adds single-touch
   ABS_PRESSURE events.

Signed-off-by: Philipp Merkel <mail@philmerk.de>
Acked-by: Stéphane Chatty <chatty@enac.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 11 insertions, 6 deletions

diff --git a/drivers/hid/hid-egalax.c b/drivers/hid/hid-egalax.c
index 8ca7f65cf2f..54b017ad258 100644
--- a/drivers/hid/hid-egalax.c
+++ b/drivers/hid/hid-egalax.c
@@ -31,7 +31,7 @@ struct egalax_data {
         bool first;             /* is this the first finger in the frame? */
         bool valid;             /* valid finger data, or just placeholder? */
         bool activity;          /* at least one active finger previously? */
-        __u16 lastx, lasty;     /* latest valid (x, y) in the frame */
+        __u16 lastx, lasty, lastz;      /* latest valid (x, y, z) in the frame */
 };
 
 static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
@@ -79,6 +79,10 @@ static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
                 case HID_DG_TIPPRESSURE:
                         hid_map_usage(hi, usage, bit, max,
                                         EV_ABS, ABS_MT_PRESSURE);
+                        /* touchscreen emulation */
+                        input_set_abs_params(hi->input, ABS_PRESSURE,
+                                                field->logical_minimum,
+                                                field->logical_maximum, 0, 0);
                         return 1;
                 }
                 return 0;
@@ -109,8 +113,8 @@ static void egalax_filter_event(struct egalax_data *td, struct input_dev *input)
         if (td->valid) {
                 /* emit multitouch events */
                 input_event(input, EV_ABS, ABS_MT_TRACKING_ID, td->id);
-                input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x);
-                input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y);
+                input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x >> 3);
+                input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y >> 3);
                 input_event(input, EV_ABS, ABS_MT_PRESSURE, td->z);
 
                 input_mt_sync(input);
@@ -121,6 +125,7 @@ static void egalax_filter_event(struct egalax_data *td, struct input_dev *input)
                  */
                 td->lastx = td->x;
                 td->lasty = td->y;
+                td->lastz = td->z;
         }
 
         /*
@@ -129,8 +134,9 @@ static void egalax_filter_event(struct egalax_data *td, struct input_dev *input)
          * the oldest on the panel, the one we want for single touch
          */
         if (!td->first && td->activity) {
-                input_event(input, EV_ABS, ABS_X, td->lastx);
-                input_event(input, EV_ABS, ABS_Y, td->lasty);
+                input_event(input, EV_ABS, ABS_X, td->lastx >> 3);
+                input_event(input, EV_ABS, ABS_Y, td->lasty >> 3);
+                input_event(input, EV_ABS, ABS_PRESSURE, td->lastz);
         }
 
         if (!td->valid) {
diff --git a/drivers/hid/usbhid/hid-quirks.c b/drivers/hid/usbhid/hid-quirks.c
index 70da3181c8a..7ff7e3d4b95 100644
--- a/drivers/hid/usbhid/hid-quirks.c
+++ b/drivers/hid/usbhid/hid-quirks.c
@@ -34,7 +34,6 @@ static const struct hid_blacklist {
         { USB_VENDOR_ID_ALPS, USB_DEVICE_ID_IBM_GAMEPAD, HID_QUIRK_BADPAD },
         { USB_VENDOR_ID_CHIC, USB_DEVICE_ID_CHIC_GAMEPAD, HID_QUIRK_BADPAD },
         { USB_VENDOR_ID_DWAV, USB_DEVICE_ID_EGALAX_TOUCHCONTROLLER, HID_QUIRK_MULTI_INPUT | HID_QUIRK_NOGET },
-        { USB_VENDOR_ID_DWAV, USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH, HID_QUIRK_MULTI_INPUT },
         { USB_VENDOR_ID_MOJO, USB_DEVICE_ID_RETRO_ADAPTER, HID_QUIRK_MULTI_INPUT },
         { USB_VENDOR_ID_HAPP, USB_DEVICE_ID_UGCI_DRIVING, HID_QUIRK_BADPAD | HID_QUIRK_MULTI_INPUT },
         { USB_VENDOR_ID_HAPP, USB_DEVICE_ID_UGCI_FLYING, HID_QUIRK_BADPAD | HID_QUIRK_MULTI_INPUT },