[PATCH v3] input: wacom: Report correct touch contact size for I5/Bamboo

Subsystems: input (keyboard, mouse, joystick, touchscreen) drivers, the rest

STALE5074d

3 messages, 3 authors, 2012-09-25 · open the first message on its own page

[PATCH v3] input: wacom: Report correct touch contact size for I5/Bamboo

From: Jason Gerecke <hidden>
Date: 2012-09-24 19:46:19

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 <redacted>
---
Changes from v2:
 * Modified WACOM_CONTACT_AREA_SCALE so that we can calculate the
   width directly, rather than going through an intermediate
   logical_diameter and physical_diameter.

 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 532d067..2543169 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);
 
 			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,

-- 
1.7.12

Re: [PATCH v3] input: wacom: Report correct touch contact size for I5/Bamboo

From: Chris Bagwell <hidden>
Date: 2012-09-25 00:10:22

On Mon, Sep 24, 2012 at 2:45 PM, Jason Gerecke [off-list ref] wrote:

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 <redacted>
---
Changes from v2:
 * Modified WACOM_CONTACT_AREA_SCALE so that we can calculate the
   width directly, rather than going through an intermediate
   logical_diameter and physical_diameter.

This version does read easier with the simplified steps.

Reviewed-by: Chris Bagwell <redacted>

quoted hunk

 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 532d067..2543169 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);

                        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,
--

1.7.12

Re: [PATCH v3] input: wacom: Report correct touch contact size for I5/Bamboo

From: Ping Cheng <hidden>
Date: 2012-09-25 01:04:48

On Mon, Sep 24, 2012 at 12:45 PM, Jason Gerecke [off-list ref] wrote:

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 <redacted>

Acked-by: Ping Cheng <redacted>

Ping

quoted hunk

---
Changes from v2:
 * Modified WACOM_CONTACT_AREA_SCALE so that we can calculate the
   width directly, rather than going through an intermediate
   logical_diameter and physical_diameter.

 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 532d067..2543169 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);

                        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,
--

1.7.12

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