Input: of_touchscreen - rework the DT parsing function

The DT parsing function currently duplicates a lot of the code to parse the
touchscreen DT properties. In order to ease further additions to this
parsing routine, rework it slightly to create new helper functions.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/of_touchscreen.c

@@ -13,6 +13,33 @@
 #include <linux/input.h>
 #include <linux/input/touchscreen.h>
 
+static u32 of_get_optional_u32(struct device_node *np,
+			       const char *property)
+{
+	u32 val = 0;
+
+	of_property_read_u32(np, property, &val);
+
+	return val;
+}
+
+static void touchscreen_set_params(struct input_dev *dev,
+				   unsigned long axis,
+				   int max, int fuzz)
+{
+	struct input_absinfo *absinfo;
+
+	if (!test_bit(axis, dev->absbit)) {
+		dev_warn(&dev->dev,
+			 "DT specifies parameters but the axis is not set up\n");
+		return;
+	}
+
+	absinfo = &dev->absinfo[axis];
+	absinfo->maximum = max;
+	absinfo->fuzz = fuzz;
+}
+
 /**
  * touchscreen_parse_of_params - parse common touchscreen DT properties
  * @dev: device that should be parsed
@@ -24,22 +51,25 @@
 void touchscreen_parse_of_params(struct input_dev *dev)
 {
 	struct device_node *np = dev->dev.parent->of_node;
-	struct input_absinfo *absinfo;
+	u32 maximum, fuzz;
 
 	input_alloc_absinfo(dev);
 	if (!dev->absinfo)
 		return;
 
-	absinfo = &dev->absinfo[ABS_X];
-	of_property_read_u32(np, "touchscreen-size-x", &absinfo->maximum);
-	of_property_read_u32(np, "touchscreen-fuzz-x", &absinfo->fuzz);
+	maximum = of_get_optional_u32(np, "touchscreen-size-x");
+	fuzz = of_get_optional_u32(np, "touchscreen-fuzz-x");
+	if (maximum || fuzz)
+		touchscreen_set_params(dev, ABS_X, maximum, fuzz);
 
-	absinfo = &dev->absinfo[ABS_Y];
-	of_property_read_u32(np, "touchscreen-size-y", &absinfo->maximum);
-	of_property_read_u32(np, "touchscreen-fuzz-y", &absinfo->fuzz);
+	maximum = of_get_optional_u32(np, "touchscreen-size-y");
+	fuzz = of_get_optional_u32(np, "touchscreen-fuzz-y");
+	if (maximum || fuzz)
+		touchscreen_set_params(dev, ABS_Y, maximum, fuzz);
 
-	absinfo = &dev->absinfo[ABS_PRESSURE];
-	of_property_read_u32(np, "touchscreen-max-pressure", &absinfo->maximum);
-	of_property_read_u32(np, "touchscreen-fuzz-pressure", &absinfo->fuzz);
+	maximum = of_get_optional_u32(np, "touchscreen-max-pressure");
+	fuzz = of_get_optional_u32(np, "touchscreen-fuzz-pressure");
+	if (maximum || fuzz)
+		touchscreen_set_params(dev, ABS_PRESSURE, maximum, fuzz);
 }
 EXPORT_SYMBOL(touchscreen_parse_of_params);