On 12/02/2013 04:02 AM, Hiroshi Doyu wrote:
...

Iterating over a property containing a list of phandles with arguments
is a common operation for device drivers. This patch adds a new
of_property_for_each_phandle_with_args() macro to make the iteration
simpler.

+const __be32 *of_phandle_iter_init(const struct device_node *np,
+				   const char *list_name,
+				   const __be32 **end)
+{
+	size_t bytes;
+	const __be32 *cur;
+
+	cur = of_get_property(np, list_name, &bytes);
+	if (bytes)
+		*end = cur + bytes / sizeof(*cur);
+
+	return cur;
+}

"bytes" doesn't seem like the correct thing to check in that if
statement. The property might exist but be zero length. Perhaps if (cur)
would be better, or just initializing *end in all cases (the value won't
be used if (!cur), so setting *end to a bogus value in that case won't
matter).

+const __be32 *of_phandle_iter_next(const char *cells_name, int cell_count,
+				   const __be32 *cur, const __be32 *end,
+				   struct of_phandle_args *out_args)

...

+	if (!cur)
+		return NULL;
+
+	if (end - cur <= 0)
+		return NULL;

Related, don't you want if (cur >= end) there; just compare the pointers
directly rather than explicitly calculating and testing the difference?