gpio: constify the data parameter to gpiochip_find()

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/gpio/gpiolib.c

@@ -1152,8 +1152,9 @@ EXPORT_SYMBOL_GPL(gpiochip_remove);
  * non-zero, this function will return to the caller and not iterate over any
  * more gpio_chips.
  */
-struct gpio_chip *gpiochip_find(void *data,
-				int (*match)(struct gpio_chip *chip, void *data))
+struct gpio_chip *gpiochip_find(const void *data,
+				int (*match)(struct gpio_chip *chip,
+					     const void *data))
 {
 	struct gpio_chip *chip = NULL;
 	unsigned long flags;

drivers/of/gpio.c

@@ -229,7 +229,7 @@ void of_gpiochip_remove(struct gpio_chip *chip)
 }
 
 /* Private function for resolving node pointer to gpio_chip */
-static int of_gpiochip_is_match(struct gpio_chip *chip, void *data)
+static int of_gpiochip_is_match(struct gpio_chip *chip, const void *data)
 {
 	return chip->of_node == data;
 }

include/asm-generic/gpio.h

@@ -142,9 +142,9 @@ extern int __must_check gpiochip_reserve(int start, int ngpio);
 /* add/remove chips */
 extern int gpiochip_add(struct gpio_chip *chip);
 extern int __must_check gpiochip_remove(struct gpio_chip *chip);
-extern struct gpio_chip *gpiochip_find(void *data,
+extern struct gpio_chip *gpiochip_find(const void *data,
 					int (*match)(struct gpio_chip *chip,
-						     void *data));
+						     const void *data));
 
 
 /* Always use the library code for GPIO management calls,