From 4e90495498cc6f1aa15e7667a695908860938b3e Mon Sep 17 00:00:00 2001 From: Jason Gerecke Date: Wed, 3 Oct 2012 17:19:11 -0700 Subject: [PATCH] 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 Reviewed-by: Chris Bagwell Acked-by: Ping Cheng Signed-off-by: Dmitry Torokhov --- drivers/input/tablet/wacom_wac.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/drivers/input/tablet/wacom_wac.c b/drivers/input/tablet/wacom_wac.c index 2a81ce375f756..ea4068b4490bd 100644 --- a/drivers/input/tablet/wacom_wac.c +++ b/drivers/input/tablet/wacom_wac.c @@ -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,