diff mbox

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

Message ID 1348515946-1674-1-git-send-email-killertofu@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Gerecke, Jason Sept. 24, 2012, 7:45 p.m. UTC
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>
---
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(-)

Comments

chris@cnpbagwell.com Sept. 25, 2012, 12:10 a.m. UTC | #1
On Mon, Sep 24, 2012 at 2:45 PM, Jason Gerecke <killertofu@gmail.com> 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 <killertofu@gmail.com>
> ---
> 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 <chris@cnpbagwell.com>

>
>  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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Ping Cheng Sept. 25, 2012, 1:04 a.m. UTC | #2
On Mon, Sep 24, 2012 at 12:45 PM, Jason Gerecke <killertofu@gmail.com> 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 <killertofu@gmail.com>

Acked-by: Ping Cheng <pingc@wacom.com>

Ping

> ---
> 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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diff mbox

Patch

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,