Input: of_touchscreen - add support for touchscreen-min-x|y

Some touchscreens, depending on the firmware and/or the digitizer, report
coordinates which never reach 0 along one or both of their axis.

This has been seen for example on the Silead touchscreens on a Onda V891w
and a Point of View mobii TAB-P800w(v2.0).

This commit adds support for touchscreen-min-x and touchscreen-min-y
device-properties which can be set to communicate the actual start
coordinates (rather then 0,0) to userspace.

This commit also drop the "(in pixels)" comment from the documentation
of the touchscreen-size-x and touchscreen-size-y properties. The comment
suggested that there is a relation between the range of reported
coordinates and the display resolution, which is only true for some
devices. The "(in pixels)" comment is replaced with "(maximum x coordinate
reported + 1)" to mirror the language describing the new touchscreen-min-x
and -min-y properties.

When set this fixes e.g. not being able to click things in the GNOME3
top-bar on the 2 example tablets.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt b/Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
index 537643e..8aff955 100644 (file)
--- a/Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
@@ -1,10 +1,12 @@
 General Touchscreen Properties:
 
 Optional properties for Touchscreens:
+ - touchscreen-min-x           : minimum x coordinate reported (0 if not set)
+ - touchscreen-min-y           : minimum y coordinate reported (0 if not set)
  - touchscreen-size-x          : horizontal resolution of touchscreen
-                                 (in pixels)
+                                 (maximum x coordinate reported + 1)
  - touchscreen-size-y          : vertical resolution of touchscreen
-                                 (in pixels)
+                                 (maximum y coordinate reported + 1)
  - touchscreen-max-pressure    : maximum reported pressure (arbitrary range
                                  dependent on the controller)
  - touchscreen-fuzz-x          : horizontal noise value of the absolute input

diff --git a/drivers/input/touchscreen/of_touchscreen.c b/drivers/input/touchscreen/of_touchscreen.c
index 9642f10..6d241d4 100644 (file)
--- a/drivers/input/touchscreen/of_touchscreen.c
+++ b/drivers/input/touchscreen/of_touchscreen.c
@@ -35,7 +35,7 @@ static bool touchscreen_get_prop_u32(struct device *dev,
 
 static void touchscreen_set_params(struct input_dev *dev,
                                   unsigned long axis,
-                                  int max, int fuzz)
+                                  int min, int max, int fuzz)
 {
        struct input_absinfo *absinfo;
 
@@ -47,6 +47,7 @@ static void touchscreen_set_params(struct input_dev *dev,
        }
 
        absinfo = &dev->absinfo[axis];
+       absinfo->minimum = min;
        absinfo->maximum = max;
        absinfo->fuzz = fuzz;
 }
@@ -68,8 +69,9 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
                                  struct touchscreen_properties *prop)
 {
        struct device *dev = input->dev.parent;
+       struct input_absinfo *absinfo;
        unsigned int axis;
-       unsigned int maximum, fuzz;
+       unsigned int minimum, maximum, fuzz;
        bool data_present;
 
        input_alloc_absinfo(input);
@@ -77,7 +79,10 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
                return;
 
        axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
-       data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-x",
+       data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
+                                               input_abs_get_min(input, axis),
+                                               &minimum) |
+                      touchscreen_get_prop_u32(dev, "touchscreen-size-x",
                                                input_abs_get_max(input,
                                                                  axis) + 1,
                                                &maximum) |
@@ -85,10 +90,13 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
                                                input_abs_get_fuzz(input, axis),
                                                &fuzz);
        if (data_present)
-               touchscreen_set_params(input, axis, maximum - 1, fuzz);
+               touchscreen_set_params(input, axis, minimum, maximum - 1, fuzz);
 
        axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
-       data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-y",
+       data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
+                                               input_abs_get_min(input, axis),
+                                               &minimum) |
+                      touchscreen_get_prop_u32(dev, "touchscreen-size-y",
                                                input_abs_get_max(input,
                                                                  axis) + 1,
                                                &maximum) |
@@ -96,7 +104,7 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
                                                input_abs_get_fuzz(input, axis),
                                                &fuzz);
        if (data_present)
-               touchscreen_set_params(input, axis, maximum - 1, fuzz);
+               touchscreen_set_params(input, axis, minimum, maximum - 1, fuzz);
 
        axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
        data_present = touchscreen_get_prop_u32(dev,
@@ -108,7 +116,7 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
                                                input_abs_get_fuzz(input, axis),
                                                &fuzz);
        if (data_present)
-               touchscreen_set_params(input, axis, maximum, fuzz);
+               touchscreen_set_params(input, axis, 0, maximum, fuzz);
 
        if (!prop)
                return;
@@ -117,13 +125,25 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
 
        prop->max_x = input_abs_get_max(input, axis);
        prop->max_y = input_abs_get_max(input, axis + 1);
+
        prop->invert_x =
                device_property_read_bool(dev, "touchscreen-inverted-x");
+       if (prop->invert_x) {
+               absinfo = &input->absinfo[axis];
+               absinfo->maximum -= absinfo->minimum;
+               absinfo->minimum = 0;
+       }
+
        prop->invert_y =
                device_property_read_bool(dev, "touchscreen-inverted-y");
+       if (prop->invert_y) {
+               absinfo = &input->absinfo[axis + 1];
+               absinfo->maximum -= absinfo->minimum;
+               absinfo->minimum = 0;
+       }
+
        prop->swap_x_y =
                device_property_read_bool(dev, "touchscreen-swapped-x-y");
-
        if (prop->swap_x_y)
                swap(input->absinfo[axis], input->absinfo[axis + 1]);
 }