Fwd: [PATCH 2/2 v2] input: wacom_w8001 - cleanup 2FG touch code

On Friday, July 15, 2016, Dmitry Torokhov [off-list ref] wrote:

On Fri, Jul 15, 2016 at 04:26:25PM -0700, Ping Cheng wrote:

quoted

input_mt_sync_frame is used by other wacom devices in wacom_wac.c
to close the frame and emulate pointer events. Let's follow them.

Touch events aren't multiplexed over the same device anymore, the
use of ABS_MT_TOOL_TYPE is superfluous.

All of our touchscreen report the finger tool events, even if it is the
only "tool" that is being used. Does it cause problems?

No, it does not cause problem, with/without ABS_MT_TOOL_TYPE being
set. Testing result shows all touch data are reported whether we
explicitly set ABS_MT_TOOL_TYPE upfront or not. Plus, ABS_MT_TOOL_TYPE
is not set in wacom.ko. We'd like to be in sync with wacom.ko.

The following comments for input_mt_report_slot_state in input-mt.c
explains the reason:

"* Reports a contact via ABS_MT_TRACKING_ID, and optionally
 * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
 * inactive, or if the tool type is changed, a new tracking id is
 * assigned to the slot. The tool type is only reported if the
 * corresponding absbit field is set."

MT_TOOL_TYPE is necessary if we report both pen and touch on the same
interface. That is not true for this series of devices any more..

quoted

Signed-off-by: Ping Cheng <redacted>
Signed-off-by: Peter Hutterer <redacted>
---
v2: moved input_abs_set_res into a separate patch, as suggested by
Dmitry.
---
 drivers/input/touchscreen/wacom_w8001.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/drivers/input/touchscreen/wacom_w8001.c b/drivers/input/touchscreen/wacom_w8001.c
index 7e807af..541a8df 100644
--- a/drivers/input/touchscreen/wacom_w8001.c
+++ b/drivers/input/touchscreen/wacom_w8001.c

@@ -170,16 +170,8 @@ static void parse_multi_touch(struct w8001 *w8001)
              }
      }

-     /* emulate single touch events when stylus is out of proximity.
-      * This is to make single touch backward support consistent
-      * across all Wacom single touch devices.
-      */
-     if (w8001->type != BTN_TOOL_PEN &&
-                         w8001->type != BTN_TOOL_RUBBER) {
-             w8001->type = count == 1 ? BTN_TOOL_FINGER : KEY_RESERVED;
-             input_mt_report_pointer_emulation(dev, true);
-     }
-
+     w8001->type = KEY_RESERVED;
+     input_mt_sync_frame(dev);
      input_sync(dev);
 }

@@ -508,7 +500,6 @@ static int w8001_setup_touch(struct w8001 *w8001, char *basename,
      case 5:
              w8001->pktlen = W8001_PKTLEN_TOUCH2FG;

-             __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);

Who is setting this bit then?

All MT related bits are set by input_mt_init_slots in input-mt.c,
including BTN_TOOL_DOUBLETAP, if necessary.

Hope this helps,

Ping

quoted

              error = input_mt_init_slots(dev, 2, 0);
              if (error) {
                      pr_debug("w8001: failed to initialize MT slots: %d\n", error);

@@ -519,8 +510,6 @@ static int w8001_setup_touch(struct w8001 *w8001, char *basename,
                                      0, touch.x, 0, 0);
              input_set_abs_params(dev, ABS_MT_POSITION_Y,
                                      0, touch.y, 0, 0);
-             input_set_abs_params(dev, ABS_MT_TOOL_TYPE,
-                                     0, MT_TOOL_MAX, 0, 0);
              input_abs_set_res(dev, ABS_MT_POSITION_X, touch.panel_res);
              input_abs_set_res(dev, ABS_MT_POSITION_Y, touch.panel_res);

--

1.8.3.1

Thanks.

--
Dmitry