linux-kernel - Re: [PATCH v3 11/13] HID: hid-multitouch: support for hovering devices

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Date:	Tue, 13 Nov 2012 17:42:39 +0100
From:	"Henrik Rydberg" <rydberg@...omail.se>
To:	Benjamin Tissoires <benjamin.tissoires@...il.com>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Jiri Kosina <jkosina@...e.cz>,
	Stephane Chatty <chatty@...c.fr>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 11/13] HID: hid-multitouch: support for hovering
 devices

On Wed, Nov 07, 2012 at 05:37:34PM +0100, Benjamin Tissoires wrote:
> Win8 devices supporting hovering must provides InRange HID field.

provide the

> The information that the finger is here but is not touching the surface
> is sent to the user space through ABS_MT_DISTANCE as required by the
> multitouch protocol.

In the absence of more detailed information, use ABS_MT_DISTANCE with
a [0,1] interval to distinguish between presence (1) and touch (0).

> 
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...il.com>
> ---
>  drivers/hid/hid-multitouch.c | 24 ++++++++++++++++++++----
>  1 file changed, 20 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index b393c6c..1f3d1e0 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -59,6 +59,7 @@ struct mt_slot {
>  	__s32 x, y, cx, cy, p, w, h;
>  	__s32 contactid;	/* the device ContactID assigned to this slot */
>  	bool touch_state;	/* is the touch valid? */
> +	bool inrange_state;	/* is the finger in proximity of the sensor? */
>  };
>  
>  struct mt_class {
> @@ -397,6 +398,12 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>  	case HID_UP_DIGITIZER:
>  		switch (usage->hid) {
>  		case HID_DG_INRANGE:
> +			if (cls->quirks & MT_QUIRK_WIN_8_CERTIFIED) {
> +				hid_map_usage(hi, usage, bit, max,
> +					EV_ABS, ABS_MT_DISTANCE);
> +				input_set_abs_params(hi->input,
> +					ABS_MT_DISTANCE, -1, 1, 0, 0);

Why [-1,1] here?

> +			}
>  			mt_store_field(usage, td, hi);
>  			td->last_field_index = field->index;
>  			return 1;
> @@ -516,6 +523,10 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
>  		if (slotnum < 0 || slotnum >= td->maxcontacts)
>  			return;
>  
> +		if (!test_bit(ABS_MT_DISTANCE, input->absbit))
> +			/* If InRange is not present, rely on TipSwitch */
> +			s->inrange_state = s->touch_state;
> +

This could be skipped, see below.

>  		if (td->mtclass.quirks & MT_QUIRK_IGNORE_DUPLICATES &&
>  		    input_mt_is_active(&input->mt->slots[slotnum]) &&
>  		    input_mt_is_used(input->mt, &input->mt->slots[slotnum]))
> @@ -523,9 +534,9 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
>  
>  		input_mt_slot(input, slotnum);
>  		input_mt_report_slot_state(input, MT_TOOL_FINGER,
> -			s->touch_state);
> -		if (s->touch_state) {
> -			/* this finger is on the screen */
> +			s->inrange_state);
> +		if (s->inrange_state) {
> +			/* this finger is in proximity of the sensor */

Using (s->touch_state || s->inrange_state) here seems simpler.

>  			int wide = (s->w > s->h);
>  			/* divided by two to match visual scale of touch */
>  			int major = max(s->w, s->h) >> 1;
> @@ -535,11 +546,14 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
>  			input_event(input, EV_ABS, ABS_MT_POSITION_Y, s->y);
>  			input_event(input, EV_ABS, ABS_MT_TOOL_X, s->cx);
>  			input_event(input, EV_ABS, ABS_MT_TOOL_Y, s->cy);
> +			input_event(input, EV_ABS, ABS_MT_DISTANCE,
> +				!s->touch_state);
>  			input_event(input, EV_ABS, ABS_MT_ORIENTATION, wide);
>  			input_event(input, EV_ABS, ABS_MT_PRESSURE, s->p);
>  			input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
>  			input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor);
> -		}
> +		} else
> +			input_event(input, EV_ABS, ABS_MT_DISTANCE, -1);

Just skip this, please.

>  	}
>  
>  	td->num_received++;
> @@ -567,6 +581,8 @@ static int mt_event(struct hid_device *hid, struct hid_field *field,
>  		case HID_DG_INRANGE:
>  			if (quirks & MT_QUIRK_VALID_IS_INRANGE)
>  				td->curvalid = value;
> +			if (quirks & MT_QUIRK_WIN_8_CERTIFIED)
> +				td->curdata.inrange_state = value;
>  			break;
>  		case HID_DG_TIPSWITCH:
>  			if (quirks & MT_QUIRK_NOT_SEEN_MEANS_UP)
> -- 
> 1.7.11.7
> 

Thanks,
Henrik
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