gpio: OF: separation of concerns

The generic GPIO library directly implement code for of_find_gpio()
which is only used with CONFIG_OF and causes compilation problems
on archs that do not even have stubs for OF functions, especially
on UM that does not implement any IO remap functions.

Move the function to gpiolib-of.c, implement a static inline stub
in gpiolib.h returning PTR_ERR(-ENOENT) if CONFIG_OF_GPIO is not
set and be done with it.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib-of.c

@@ -114,6 +114,45 @@ int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
 }
 EXPORT_SYMBOL(of_get_named_gpio_flags);
 
+struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
+			       unsigned int idx,
+			       enum gpio_lookup_flags *flags)
+{
+	char prop_name[32]; /* 32 is max size of property name */
+	enum of_gpio_flags of_flags;
+	struct gpio_desc *desc;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
+		if (con_id)
+			snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
+				 gpio_suffixes[i]);
+		else
+			snprintf(prop_name, sizeof(prop_name), "%s",
+				 gpio_suffixes[i]);
+
+		desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
+						&of_flags);
+		if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
+			break;
+	}
+
+	if (IS_ERR(desc))
+		return desc;
+
+	if (of_flags & OF_GPIO_ACTIVE_LOW)
+		*flags |= GPIO_ACTIVE_LOW;
+
+	if (of_flags & OF_GPIO_SINGLE_ENDED) {
+		if (of_flags & OF_GPIO_ACTIVE_LOW)
+			*flags |= GPIO_OPEN_DRAIN;
+		else
+			*flags |= GPIO_OPEN_SOURCE;
+	}
+
+	return desc;
+}
+
 /**
  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
  * @np:		device node to get GPIO from

drivers/gpio/gpiolib.c

@@ -2883,45 +2883,6 @@ void gpiod_remove_lookup_table(struct gpiod_lookup_table *table)
 	mutex_unlock(&gpio_lookup_lock);
 }
 
-static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
-				      unsigned int idx,
-				      enum gpio_lookup_flags *flags)
-{
-	char prop_name[32]; /* 32 is max size of property name */
-	enum of_gpio_flags of_flags;
-	struct gpio_desc *desc;
-	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
-		if (con_id)
-			snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
-				 gpio_suffixes[i]);
-		else
-			snprintf(prop_name, sizeof(prop_name), "%s",
-				 gpio_suffixes[i]);
-
-		desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
-						&of_flags);
-		if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
-			break;
-	}
-
-	if (IS_ERR(desc))
-		return desc;
-
-	if (of_flags & OF_GPIO_ACTIVE_LOW)
-		*flags |= GPIO_ACTIVE_LOW;
-
-	if (of_flags & OF_GPIO_SINGLE_ENDED) {
-		if (of_flags & OF_GPIO_ACTIVE_LOW)
-			*flags |= GPIO_OPEN_DRAIN;
-		else
-			*flags |= GPIO_OPEN_SOURCE;
-	}
-
-	return desc;
-}
-
 static struct gpio_desc *acpi_find_gpio(struct device *dev,
 					const char *con_id,
 					unsigned int idx,

drivers/gpio/gpiolib.h

@@ -20,6 +20,7 @@
 
 enum of_gpio_flags;
 enum gpiod_flags;
+enum gpio_lookup_flags;
 struct acpi_device;
 
 /**
@@ -86,6 +87,21 @@ struct acpi_gpio_info {
 /* gpio suffixes used for ACPI and device tree lookup */
 static const char * const gpio_suffixes[] = { "gpios", "gpio" };
 
+#ifdef CONFIG_OF_GPIO
+struct gpio_desc *of_find_gpio(struct device *dev,
+			       const char *con_id,
+			       unsigned int idx,
+			       enum gpio_lookup_flags *flags);
+#else
+static inline struct gpio_desc *of_find_gpio(struct device *dev,
+					     const char *con_id,
+					     unsigned int idx,
+					     enum gpio_lookup_flags *flags)
+{
+	return ERR_PTR(-ENOENT);
+}
+#endif /* CONFIG_OF_GPIO */
+
 #ifdef CONFIG_ACPI
 void acpi_gpiochip_add(struct gpio_chip *chip);
 void acpi_gpiochip_remove(struct gpio_chip *chip);