Re: [PATCH] Input: Change BTN_TOOL_FINGER falg when HOVER event trigger

From: 'Dmitry Torokhov'
Date: Thu Mar 31 2016 - 14:17:38 EST


On Wed, Mar 30, 2016 at 05:49:12PM +0800, DusonLin wrote:
> Hello Dmitry,
>
> Please check my response below, thanks.
>
>
> -----Original Message-----
> From: 'Dmitry Torokhov' [mailto:dmitry.torokhov@xxxxxxxxx]
> Sent: Wednesday, March 30, 2016 10:31 AM
> To: DusonLin
> Cc: Linux-kernel@xxxxxxxxxxxxxxx; linux-input@xxxxxxxxxxxxxxx; 'Charles Mooney'; 'jeff'; 'Phoenix'
> Subject: Re: [PATCH] Input: Change BTN_TOOL_FINGER falg when HOVER event trigger
>
> Hi Duson,
>
> On Wed, Mar 30, 2016 at 10:02:02AM +0800, DusonLin wrote:
> > Only ABS_DISTANCE is not enough for upper OS to distiguish hover
> > event be triggered from object form faraway to and close touchpad
> > surface or from object prepare to leave the touchpad surface. We add
> > BNT_TOOL_FINGER to help it.
> >
> > Object_at_faraway object_at_hover_area object_touch_touchpad
> > BTN_TOUCH 0 0 1
> > BTN_TOOL_FINGER 0 1 1
> > ABS_DISTANCE 0 1 0
> >
> > Signed-off by: Duson Lin <dusonlin@xxxxxxxxxx>
> > ---
> > drivers/input/mouse/elan_i2c_core.c | 14 +++++++++-----
> > 1 file changed, 9 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/input/mouse/elan_i2c_core.c
> > b/drivers/input/mouse/elan_i2c_core.c
> > index 2f58985..9392a8c 100644
> > --- a/drivers/input/mouse/elan_i2c_core.c
> > +++ b/drivers/input/mouse/elan_i2c_core.c
> > @@ -4,7 +4,7 @@
> > * Copyright (c) 2013 ELAN Microelectronics Corp.
> > *
> > * Author: ææç (Duson Lin) <dusonlin@xxxxxxxxxx>
> > - * Version: 1.6.0
> > + * Version: 1.6.1
> > *
> > * Based on cyapa driver:
> > * copyright (c) 2011-2012 Cypress Semiconductor, Inc.
> > @@ -845,23 +845,27 @@ static void elan_report_absolute(struct
> > elan_tp_data *data, u8 *packet) {
> > struct input_dev *input = data->input;
> > u8 *finger_data = &packet[ETP_FINGER_DATA_OFFSET];
> > - int i;
> > + int i, valid_count = 0;
>
> This appears all whitespace-damaged.
> [duson] will do.
>
> > u8 tp_info = packet[ETP_TOUCH_INFO_OFFSET];
> > u8 hover_info = packet[ETP_HOVER_INFO_OFFSET];
> > bool contact_valid, hover_event;
> >
> > - hover_event = hover_info & 0x40;
> > + hover_event = (hover_info & 0x40);
>
> We do not need parentheses here.
> [duson] will do.
>
> > for (i = 0; i < ETP_MAX_FINGERS; i++) {
> > contact_valid = tp_info & (1U << (3 + i));
> > elan_report_contact(data, i, contact_valid,
> > finger_data);
> >
> > - if (contact_valid)
> > + if (contact_valid) {
> > finger_data += ETP_FINGER_DATA_LEN;
> > + valid_count++;
> > + }
> > }
> >
> > input_report_key(input, BTN_LEFT, tp_info & 0x01);
> > + input_report_key(input, BTN_TOOL_FINGER,
> > + ((hover_event != 0) | (valid_count > 0)));
>
> You do not want to use "bitwise or" here.
>
> > input_report_abs(input, ABS_DISTANCE, hover_event != 0);
> > - input_mt_report_pointer_emulation(input, true);
> > + input_mt_report_pointer_emulation(input, false);
>
> I wonder if we should teach input_mt_report_pointer_emulation() to handle hover properly.
> [duson] But, it looks like the hover is not standard function and not all of touchpad support this function,
> Even though, we still teach inpu_mt_report_pointer_emulation() to handle this function?

Yes, something like this:

If device supports ABS_DISTANCE and does not support ABS_MT_DISTANCE and
ABS_DISTANCE != 0 is reported in current frame and there are no other
contacts then report BTN_TOOL_FINGER.

Thanks.

--
Dmitry