3 files changed, 54 insertions, 8 deletions

diff --git a/Documentation/input/multi-touch-protocol.rst b/Documentation/input/multi-touch-protocol.rst
index 8035868c56bc..b51751a0cd5d 100644
--- a/Documentation/input/multi-touch-protocol.rst
+++ b/Documentation/input/multi-touch-protocol.rst
@@ -269,10 +269,11 @@ ABS_MT_ORIENTATION
     The orientation of the touching ellipse. The value should describe a signed
     quarter of a revolution clockwise around the touch center. The signed value
     range is arbitrary, but zero should be returned for an ellipse aligned with
-    the Y axis of the surface, a negative value when the ellipse is turned to
-    the left, and a positive value when the ellipse is turned to the
-    right. When completely aligned with the X axis, the range max should be
-    returned.
+    the Y axis (north) of the surface, a negative value when the ellipse is
+    turned to the left, and a positive value when the ellipse is turned to the
+    right. When aligned with the X axis in the positive direction, the range
+    max should be returned; when aligned with the X axis in the negative
+    direction, the range -max should be returned.
 
     Touch ellipsis are symmetrical by default. For devices capable of true 360
     degree orientation, the reported orientation must exceed the range max to
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 76088f2cf598..3b4739bde05d 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -85,11 +85,12 @@ MODULE_LICENSE("GPL");
 #define MT_IO_FLAGS_PENDING_SLOTS       2
 
 struct mt_slot {
-        __s32 x, y, cx, cy, p, w, h;
+        __s32 x, y, cx, cy, p, w, h, a;
         __s32 contactid;        /* the device ContactID assigned to this slot */
         bool touch_state;       /* is the touch valid? */
         bool inrange_state;     /* is the finger in proximity of the sensor? */
         bool confidence_state;  /* is the touch made by a finger? */
+        bool has_azimuth;       /* the contact reports azimuth */
 };
 
 struct mt_class {
@@ -586,8 +587,15 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
                         if (!(cls->quirks & MT_QUIRK_NO_AREA)) {
                                 set_abs(hi->input, ABS_MT_TOUCH_MINOR, field,
                                         cls->sn_height);
-                                input_set_abs_params(hi->input,
-                                        ABS_MT_ORIENTATION, 0, 1, 0, 0);
+
+                                /*
+                                 * Only set ABS_MT_ORIENTATION if it is not
+                                 * already set by the HID_DG_AZIMUTH usage.
+                                 */
+                                if (!test_bit(ABS_MT_ORIENTATION,
+                                                hi->input->absbit))
+                                        input_set_abs_params(hi->input,
+                                                ABS_MT_ORIENTATION, 0, 1, 0, 0);
                         }
                         mt_store_field(usage, td, hi);
                         return 1;
@@ -618,6 +626,21 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
                         td->cc_index = field->index;
                         td->cc_value_index = usage->usage_index;
                         return 1;
+                case HID_DG_AZIMUTH:
+                        hid_map_usage(hi, usage, bit, max,
+                                EV_ABS, ABS_MT_ORIENTATION);
+                        /*
+                         * Azimuth has the range of [0, MAX) representing a full
+                         * revolution. Set ABS_MT_ORIENTATION to a quarter of
+                         * MAX according the definition of ABS_MT_ORIENTATION
+                         */
+                        input_set_abs_params(hi->input, ABS_MT_ORIENTATION,
+                                -field->logical_maximum / 4,
+                                field->logical_maximum / 4,
+                                cls->sn_move ?
+                                field->logical_maximum / cls->sn_move : 0, 0);
+                        mt_store_field(usage, td, hi);
+                        return 1;
                 case HID_DG_CONTACTMAX:
                         /* we don't set td->last_slot_field as contactcount and
                          * contact max are global to the report */
@@ -710,6 +733,10 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
                         int wide = (s->w > s->h);
                         int major = max(s->w, s->h);
                         int minor = min(s->w, s->h);
+                        int orientation = wide;
+
+                        if (s->has_azimuth)
+                                orientation = s->a;
 
                         /*
                          * divided by two to match visual scale of touch
@@ -726,7 +753,8 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
                         input_event(input, EV_ABS, ABS_MT_TOOL_Y, s->cy);
                         input_event(input, EV_ABS, ABS_MT_DISTANCE,
                                 !s->touch_state);
-                        input_event(input, EV_ABS, ABS_MT_ORIENTATION, wide);
+                        input_event(input, EV_ABS, ABS_MT_ORIENTATION,
+                                orientation);
                         input_event(input, EV_ABS, ABS_MT_PRESSURE, s->p);
                         input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
                         input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor);
@@ -850,6 +878,22 @@ static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,
                         break;
                 case HID_DG_CONTACTCOUNT:
                         break;
+                case HID_DG_AZIMUTH:
+                        /*
+                         * Azimuth is counter-clockwise and ranges from [0, MAX)
+                         * (a full revolution). Convert it to clockwise ranging
+                         * [-MAX/2, MAX/2].
+                         *
+                         * Note that ABS_MT_ORIENTATION require us to report
+                         * the limit of [-MAX/4, MAX/4], but the value can go
+                         * out of range to [-MAX/2, MAX/2] to report an upside
+                         * down ellipsis.
+                         */
+                        if (value > field->logical_maximum / 2)
+                                value -= field->logical_maximum;
+                        td->curdata.a = -value;
+                        td->curdata.has_azimuth = true;
+                        break;
                 case HID_DG_TOUCH:
                         /* do nothing */
                         break;
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 39cdeb205caa..091a81cf330f 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -281,6 +281,7 @@ struct hid_item {
 
 #define HID_DG_DEVICECONFIG     0x000d000e
 #define HID_DG_DEVICESETTINGS   0x000d0023
+#define HID_DG_AZIMUTH          0x000d003f
 #define HID_DG_CONFIDENCE       0x000d0047
 #define HID_DG_WIDTH            0x000d0048
 #define HID_DG_HEIGHT           0x000d0049