HID: export hidinput_calc_abs_res

Exporting the function allows us to calculate the resolution in third
party drivers like hid-multitouch.
This patch also complete the function with additional valid axes.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-input.c

@@ -208,7 +208,7 @@ static int hidinput_setkeycode(struct input_dev *dev,
  * Only exponent 1 length units are processed. Centimeters and inches are
  * converted to millimeters. Degrees are converted to radians.
  */
-static __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
+__s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
 {
 	__s32 unit_exponent = field->unit_exponent;
 	__s32 logical_extents = field->logical_maximum -
@@ -229,6 +229,12 @@ static __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
 	case ABS_X:
 	case ABS_Y:
 	case ABS_Z:
+	case ABS_MT_POSITION_X:
+	case ABS_MT_POSITION_Y:
+	case ABS_MT_TOOL_X:
+	case ABS_MT_TOOL_Y:
+	case ABS_MT_TOUCH_MAJOR:
+	case ABS_MT_TOUCH_MINOR:
 		if (field->unit == 0x11) {		/* If centimeters */
 			/* Convert to millimeters */
 			unit_exponent += 1;
@@ -283,6 +289,7 @@ static __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
 	/* Calculate resolution */
 	return logical_extents / physical_extents;
 }
+EXPORT_SYMBOL_GPL(hidinput_calc_abs_res);
 
 #ifdef CONFIG_HID_BATTERY_STRENGTH
 static enum power_supply_property hidinput_battery_props[] = {

drivers/hid/hid-multitouch.c

@@ -297,6 +297,7 @@ static void set_abs(struct input_dev *input, unsigned int code,
 	int fmax = field->logical_maximum;
 	int fuzz = snratio ? (fmax - fmin) / snratio : 0;
 	input_set_abs_params(input, code, fmin, fmax, fuzz, 0);
+	input_abs_set_res(input, code, hidinput_calc_abs_res(field, code));
 }
 
 static void mt_store_field(struct hid_usage *usage, struct mt_device *td,

include/linux/hid.h

@@ -706,6 +706,7 @@ int hid_input_report(struct hid_device *, int type, u8 *, int, int);
 int hidinput_find_field(struct hid_device *hid, unsigned int type, unsigned int code, struct hid_field **field);
 struct hid_field *hidinput_get_led_field(struct hid_device *hid);
 unsigned int hidinput_count_leds(struct hid_device *hid);
+__s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code);
 void hid_output_report(struct hid_report *report, __u8 *data);
 struct hid_device *hid_allocate_device(void);
 struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id);