HID: wacom: Add angular resolution data to some ABS axes

Provide the resolution of several angular axes (tilt, pen rotation, puck
rotation) to userspace. Because these values are natively degree-based, we
need to convert them to into units/radian as required by the input_absinfo
struct. To ensure wraparound behaves properly for the rotation axes, the
converted value was rounded up rather than rounded nearest.

Notably, the touchring axes (ABS_WHEEL and ABS_THROTTLE) are left without a
a declared resolution because the their low resolution cannot be accurately
represented (the worst-case rounding-induced error would be ~16 degrees).
Pre-scaling the values and range by at least 10x would reduce the error in
the resolution to acceptable levels, but the xf86-input-wacom driver is not
able to use pre-scaled values for these axes at this time.

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Reviewed-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 74c9fbde5695..9565d31262ec 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1930,7 +1930,9 @@ static void wacom_setup_cintiq(struct wacom_wac *wacom_wac)
                              0, wacom_wac->features.distance_max, 0, 0);
         input_set_abs_params(input_dev, ABS_WHEEL, 0, 1023, 0, 0);
         input_set_abs_params(input_dev, ABS_TILT_X, -64, 63, 0, 0);
+        input_abs_set_res(input_dev, ABS_TILT_X, 57);
         input_set_abs_params(input_dev, ABS_TILT_Y, -64, 63, 0, 0);
+        input_abs_set_res(input_dev, ABS_TILT_Y, 57);
 }
 
 static void wacom_setup_intuos(struct wacom_wac *wacom_wac)
@@ -1950,6 +1952,7 @@ static void wacom_setup_intuos(struct wacom_wac *wacom_wac)
         __set_bit(BTN_TOOL_LENS, input_dev->keybit);
 
         input_set_abs_params(input_dev, ABS_RZ, -900, 899, 0, 0);
+        input_abs_set_res(input_dev, ABS_RZ, 287);
         input_set_abs_params(input_dev, ABS_THROTTLE, -1023, 1023, 0, 0);
 }
 
@@ -2092,6 +2095,7 @@ int wacom_setup_pentouch_input_capabilities(struct input_dev *input_dev,
 
         case WACOM_24HD:
                 input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
+                input_abs_set_res(input_dev, ABS_Z, 287);
                 input_set_abs_params(input_dev, ABS_THROTTLE, 0, 71, 0, 0);
                 /* fall through */
 
@@ -2106,6 +2110,7 @@ int wacom_setup_pentouch_input_capabilities(struct input_dev *input_dev,
         case WACOM_BEE:
         case CINTIQ:
                 input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
+                input_abs_set_res(input_dev, ABS_Z, 287);
 
                 __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
 
@@ -2114,6 +2119,7 @@ int wacom_setup_pentouch_input_capabilities(struct input_dev *input_dev,
 
         case WACOM_13HD:
                 input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
+                input_abs_set_res(input_dev, ABS_Z, 287);
                 __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
                 wacom_setup_cintiq(wacom_wac);
                 break;
@@ -2122,6 +2128,7 @@ int wacom_setup_pentouch_input_capabilities(struct input_dev *input_dev,
         case INTUOS3L:
         case INTUOS3S:
                 input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
+                input_abs_set_res(input_dev, ABS_Z, 287);
                 /* fall through */
 
         case INTUOS:
@@ -2144,6 +2151,7 @@ int wacom_setup_pentouch_input_capabilities(struct input_dev *input_dev,
                                               0, 0);
 
                         input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
+                        input_abs_set_res(input_dev, ABS_Z, 287);
 
                         wacom_setup_intuos(wacom_wac);
                 } else if (features->device_type == BTN_TOOL_FINGER) {
@@ -2162,6 +2170,7 @@ int wacom_setup_pentouch_input_capabilities(struct input_dev *input_dev,
         case INTUOS4L:
         case INTUOS4S:
                 input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
+                input_abs_set_res(input_dev, ABS_Z, 287);
                 wacom_setup_intuos(wacom_wac);
 
                 __set_bit(INPUT_PROP_POINTER, input_dev->propbit);
@@ -2264,6 +2273,7 @@ int wacom_setup_pentouch_input_capabilities(struct input_dev *input_dev,
 
         case CINTIQ_HYBRID:
                 input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
+                input_abs_set_res(input_dev, ABS_Z, 287);
                 __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
 
                 wacom_setup_cintiq(wacom_wac);