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Input: wacom - report correct touch contact size for I5/Bamboo 

This changes how the touch packets for Intuos5 and 3rd-gen Bamboo
are interpreted, so that proper values for the MAJOR and MINOR
axes are reported. Instead of using the amplitude field (data[6]),
we use the size field (data[5]) and do some calculation to
transform it from a scaled-down area into axis lengths.

Note that even though we assume a circular contact, both MAJOR and
MINOR are reported since the resolution of the X and Y axes differ.

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Reviewed-by: Chris Bagwell <chris@cnpbagwell.com>
Acked-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Jason Gerecke 2012-10-03 17:19:11 -07:00 committed by Dmitry Torokhov
parent 7774036808
commit 4e90495498
1 changed files with 22 additions and 4 deletions
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26
drivers/input/tablet/wacom_wac.c
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@ -25,6 +25,11 @@
#define WACOM_INTUOS_RES 100
#define WACOM_INTUOS3_RES 200
/* Scale factor relating reported contact size to logical contact area.
* 2^14/pi is a good approximation on Intuos5 and 3rd-gen Bamboo
*/
#define WACOM_CONTACT_AREA_SCALE 2607
static int wacom_penpartner_irq(struct wacom_wac *wacom)
{
unsigned char *data = wacom->data;
@ -1043,11 +1048,19 @@ static void wacom_bpt3_touch_msg(struct wacom_wac *wacom, unsigned char *data)
if (touch) {
int x = (data[2] << 4) | (data[4] >> 4);
int y = (data[3] << 4) | (data[4] & 0x0f);
int w = data[6];
int a = data[5];
// "a" is a scaled-down area which we assume is roughly
// circular and which can be described as: a=(pi*r^2)/C.
int x_res = input_abs_get_res(input, ABS_X);
int y_res = input_abs_get_res(input, ABS_Y);
int width = 2 * int_sqrt(a * WACOM_CONTACT_AREA_SCALE);
int height = width * y_res / x_res;
input_report_abs(input, ABS_MT_POSITION_X, x);
input_report_abs(input, ABS_MT_POSITION_Y, y);
input_report_abs(input, ABS_MT_TOUCH_MAJOR, w);
input_report_abs(input, ABS_MT_TOUCH_MAJOR, width);
input_report_abs(input, ABS_MT_TOUCH_MINOR, height);
}
}
@ -1533,7 +1546,9 @@ int wacom_setup_input_capabilities(struct input_dev *input_dev,
input_mt_init_slots(input_dev, features->touch_max, 0);
input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
0, 255, 0, 0);
0, features->x_max, 0, 0);
input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR,
0, features->y_max, 0, 0);
input_set_abs_params(input_dev, ABS_MT_POSITION_X,
0, features->x_max,
@ -1641,7 +1656,10 @@ int wacom_setup_input_capabilities(struct input_dev *input_dev,
input_set_abs_params(input_dev,
ABS_MT_TOUCH_MAJOR,
0, 255, 0, 0);
0, features->x_max, 0, 0);
input_set_abs_params(input_dev,
ABS_MT_TOUCH_MINOR,
0, features->y_max, 0, 0);
}
input_set_abs_params(input_dev, ABS_MT_POSITION_X,