gpio: Make of_count_named_gpios() use new of_count_phandle_with_args()

This patch replaces the horribly coded of_count_named_gpios() with a
call to of_count_phandle_with_args() which is far more efficient. This
also changes the return value of of_gpio_count() & of_gpio_named_count()
from 'unsigned int' to 'int' so that it can return an error code. All
the users of that function are fixed up to correctly handle a negative
return value.

v2: Split GPIO portion into a separate patch

Tested-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>

1 files changed, 23 insertions, 17 deletions

diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index c454f5796747..a83dc6f5008e 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -50,9 +50,6 @@ static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
 extern int of_get_named_gpio_flags(struct device_node *np,
 		const char *list_name, int index, enum of_gpio_flags *flags);
 
-extern unsigned int of_gpio_named_count(struct device_node *np,
-					const char* propname);
-
 extern int of_mm_gpiochip_add(struct device_node *np,
 			      struct of_mm_gpio_chip *mm_gc);
 
@@ -71,12 +68,6 @@ static inline int of_get_named_gpio_flags(struct device_node *np,
 	return -ENOSYS;
 }
 
-static inline unsigned int of_gpio_named_count(struct device_node *np,
-					const char* propname)
-{
-	return 0;
-}
-
 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
 				       const struct of_phandle_args *gpiospec,
 				       u32 *flags)
@@ -90,22 +81,37 @@ static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
 #endif /* CONFIG_OF_GPIO */
 
 /**
- * of_gpio_count - Count GPIOs for a device
+ * of_gpio_named_count() - Count GPIOs for a device
  * @np:		device node to count GPIOs for
+ * @propname:	property name containing gpio specifier(s)
  *
  * The function returns the count of GPIOs specified for a node.
+ * Note that the empty GPIO specifiers count too. Returns either
+ *   Number of gpios defined in property,
+ *   -EINVAL for an incorrectly formed gpios property, or
+ *   -ENOENT for a missing gpios property
  *
- * Note that the empty GPIO specifiers counts too. For example,
- *
+ * Example:
  * gpios = <0
- *          &pio1 1 2
+ *          &gpio1 1 2
  *          0
- *          &pio2 3 4>;
+ *          &gpio2 3 4>;
+ *
+ * The above example defines four GPIOs, two of which are not specified.
+ * This function will return '4'
+ */
+static inline int of_gpio_named_count(struct device_node *np, const char* propname)
+{
+	return of_count_phandle_with_args(np, propname, "#gpio-cells");
+}
+
+/**
+ * of_gpio_count() - Count GPIOs for a device
+ * @np:		device node to count GPIOs for
  *
- * defines four GPIOs (so this function will return 4), two of which
- * are not specified.
+ * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
  */
-static inline unsigned int of_gpio_count(struct device_node *np)
+static inline int of_gpio_count(struct device_node *np)
 {
 	return of_gpio_named_count(np, "gpios");
 }