HID: haptic: add functions handling events

Implement hid_haptic_handle_press_release() which generates haptic feedback
as well as saves the pressed state of the haptic device.
Add functions to increase and reset the state of the pressure detected by
the device.

Signed-off-by: Angela Czubak <aczubak@google.com>
Co-developed-by: Jonathan Denose <jdenose@google.com>
Signed-off-by: Jonathan Denose <jdenose@google.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

Author: Angela Czubak

drivers/hid/hid-haptic.c

@@ -50,8 +50,13 @@ EXPORT_SYMBOL_GPL(hid_haptic_feature_mapping);
 bool hid_haptic_check_pressure_unit(struct hid_haptic_device *haptic,
 				    struct hid_input *hi, struct hid_field *field)
 {
-	if (field->unit == HID_UNIT_GRAM || field->unit == HID_UNIT_NEWTON)
+	if (field->unit == HID_UNIT_GRAM || field->unit == HID_UNIT_NEWTON) {
+		haptic->force_logical_minimum = field->logical_minimum;
+		haptic->force_physical_minimum = field->physical_minimum;
+		haptic->force_resolution = input_abs_get_res(hi->input,
+							     ABS_MT_PRESSURE);
 		return true;
+	}
 	return false;
 }
 EXPORT_SYMBOL_GPL(hid_haptic_check_pressure_unit);
@@ -508,3 +513,16 @@ int hid_haptic_init(struct hid_device *hdev,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(hid_haptic_init);
+
+void hid_haptic_pressure_reset(struct hid_haptic_device *haptic)
+{
+	haptic->pressure_sum = 0;
+}
+EXPORT_SYMBOL_GPL(hid_haptic_pressure_reset);
+
+void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
+				 __s32 pressure)
+{
+	haptic->pressure_sum += pressure;
+}
+EXPORT_SYMBOL_GPL(hid_haptic_pressure_increase);

drivers/hid/hid-haptic.h

@@ -70,6 +70,10 @@ int hid_haptic_input_configured(struct hid_device *hdev,
 				struct hid_haptic_device *haptic,
 				struct hid_input *hi);
 int hid_haptic_init(struct hid_device *hdev, struct hid_haptic_device **haptic_ptr);
+void hid_haptic_handle_press_release(struct hid_haptic_device *haptic);
+void hid_haptic_pressure_reset(struct hid_haptic_device *haptic);
+void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
+				  __s32 pressure);
 #else
 static inline
 void hid_haptic_feature_mapping(struct hid_device *hdev,
@@ -103,4 +107,15 @@ int hid_haptic_init(struct hid_device *hdev, struct hid_haptic_device **haptic_p
 {
 	return 0;
 }
+static inline
+void hid_haptic_handle_press_release(struct hid_haptic_device *haptic)
+{}
+static inline
+void hid_haptic_pressure_reset(struct hid_haptic_device *haptic)
+{}
+static inline
+void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
+				  __s32 pressure)
+{}
 #endif
+