of: create of_phandle_args to simplify return of phandle parsing data

of_parse_phandle_with_args() needs to return quite a bit of data.  Rather
than making each datum a separate **out_ argument, this patch creates
struct of_phandle_args to contain all the returned data and reworks the
user of the function.  This patch also enables of_parse_phandle_with_args()
to return the device node pointer for the phandle node.

This patch also ends up being fairly major surgery to
of_parse_handle_with_args().  The existing structure didn't work well
when extending to use of_phandle_args, and I discovered bugs during testing.
I also took the opportunity to rename the function to be like the
existing of_parse_phandle().

v2: - moved declaration of of_phandle_args to fix compile on non-DT builds
    - fixed incorrect index in example usage
    - fixed incorrect return code handling for empty entries

Reviewed-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

3 files changed, 18 insertions, 8 deletions

diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 6b10bdc..d466c8d 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -4,6 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/errno.h>
+#include <linux/of.h>
 
 #ifdef CONFIG_GPIOLIB
 
@@ -128,8 +129,8 @@ struct gpio_chip {
 	 */
 	struct device_node *of_node;
 	int of_gpio_n_cells;
-	int (*of_xlate)(struct gpio_chip *gc, struct device_node *np,
-		        const void *gpio_spec, u32 *flags);
+	int (*of_xlate)(struct gpio_chip *gc,
+		        const struct of_phandle_args *gpiospec, u32 *flags);
 #endif
 };
 
diff --git a/include/linux/of.h b/include/linux/of.h
index 4948552..ea44fd7 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -65,6 +65,13 @@ struct device_node {
 #endif
 };
 
+#define MAX_PHANDLE_ARGS 8
+struct of_phandle_args {
+	struct device_node *np;
+	int args_count;
+	uint32_t args[MAX_PHANDLE_ARGS];
+};
+
 #ifdef CONFIG_OF
 
 /* Pointer for first entry in chain of all nodes. */
@@ -230,9 +237,9 @@ extern int of_modalias_node(struct device_node *node, char *modalias, int len);
 extern struct device_node *of_parse_phandle(struct device_node *np,
 					    const char *phandle_name,
 					    int index);
-extern int of_parse_phandles_with_args(struct device_node *np,
+extern int of_parse_phandle_with_args(struct device_node *np,
 	const char *list_name, const char *cells_name, int index,
-	struct device_node **out_node, const void **out_args);
+	struct of_phandle_args *out_args);
 
 extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
 extern int of_alias_get_id(struct device_node *np, const char *stem);
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index 52280a2..b254052 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -18,6 +18,7 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/gpio.h>
+#include <linux/of.h>
 
 struct device_node;
 
@@ -57,8 +58,9 @@ extern int of_mm_gpiochip_add(struct device_node *np,
 extern void of_gpiochip_add(struct gpio_chip *gc);
 extern void of_gpiochip_remove(struct gpio_chip *gc);
 extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
-extern int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
-				const void *gpio_spec, u32 *flags);
+extern int of_gpio_simple_xlate(struct gpio_chip *gc,
+				const struct of_phandle_args *gpiospec,
+				u32 *flags);
 
 #else /* CONFIG_OF_GPIO */
 
@@ -75,8 +77,8 @@ static inline unsigned int of_gpio_count(struct device_node *np)
 }
 
 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
-				       struct device_node *np,
-				       const void *gpio_spec, u32 *flags)
+				       const struct of_phandle_args *gpiospec,
+				       u32 *flags)
 {
 	return -ENOSYS;
 }