gpio: add gpio_is_valid() to omap_gpio API

Add gpio_is_valid() to omap_gpio API

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
diff --git a/arch/arm/include/asm/omap_gpio.h b/arch/arm/include/asm/omap_gpio.h
index 516cc42..1ebfa86 100644
--- a/arch/arm/include/asm/omap_gpio.h
+++ b/arch/arm/include/asm/omap_gpio.h
@@ -49,4 +49,11 @@
 
 #define METHOD_GPIO_24XX	4
 
+/**
+ * Check if gpio is valid.
+ *
+ * @param gpio	GPIO number
+ * @return 1 if ok, 0 on error
+ */
+int gpio_is_valid(int gpio);
 #endif /* _GPIO_H_ */
diff --git a/drivers/gpio/omap_gpio.c b/drivers/gpio/omap_gpio.c
index fc89f2a..a30d7f0 100644
--- a/drivers/gpio/omap_gpio.c
+++ b/drivers/gpio/omap_gpio.c
@@ -53,18 +53,14 @@
 	return gpio & 0x1f;
 }
 
-static inline int gpio_valid(int gpio)
+int gpio_is_valid(int gpio)
 {
-	if (gpio < 0)
-		return -1;
-	if (gpio < 192)
-		return 0;
-	return -1;
+	return (gpio >= 0) && (gpio < 192);
 }
 
 static int check_gpio(int gpio)
 {
-	if (gpio_valid(gpio) < 0) {
+	if (!gpio_is_valid(gpio)) {
 		printf("ERROR : check_gpio: invalid GPIO %d\n", gpio);
 		return -1;
 	}