of: Add new helper of_parse_phandles_with_args()

The helper is factored out of of_get_gpio(). Will be used by the QE
pin multiplexing functions (they need to parse the gpios = <> too).

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/drivers/of/base.c b/drivers/of/base.c
index cd1ce7ab8517800f700e77ad661f9b7dd3bdb581..4270eb4a26a1337c72164bce2f71ebca850bbd8b 100644 (file)
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -458,3 +458,112 @@ int of_modalias_node(struct device_node *node, char *modalias, int len)
 }
 EXPORT_SYMBOL_GPL(of_modalias_node);
 
+/**
+ * of_parse_phandles_with_args - Find a node pointed by phandle in a list
+ * @np:                pointer to a device tree node containing a list
+ * @list_name: property name that contains a list
+ * @cells_name:        property name that specifies phandles' arguments count
+ * @index:     index of a phandle to parse out
+ * @out_node:  pointer to device_node struct pointer (will be filled)
+ * @out_args:  pointer to arguments pointer (will be filled)
+ *
+ * This function is useful to parse lists of phandles and their arguments.
+ * Returns 0 on success and fills out_node and out_args, on error returns
+ * appropriate errno value.
+ *
+ * Example:
+ *
+ * phandle1: node1 {
+ *     #list-cells = <2>;
+ * }
+ *
+ * phandle2: node2 {
+ *     #list-cells = <1>;
+ * }
+ *
+ * node3 {
+ *     list = <&phandle1 1 2 &phandle2 3>;
+ * }
+ *
+ * To get a device_node of the `node2' node you may call this:
+ * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
+ */
+int of_parse_phandles_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)
+{
+       int ret = -EINVAL;
+       const u32 *list;
+       const u32 *list_end;
+       int size;
+       int cur_index = 0;
+       struct device_node *node = NULL;
+       const void *args;
+
+       list = of_get_property(np, list_name, &size);
+       if (!list) {
+               ret = -ENOENT;
+               goto err0;
+       }
+       list_end = list + size / sizeof(*list);
+
+       while (list < list_end) {
+               const u32 *cells;
+               const phandle *phandle;
+
+               phandle = list;
+               args = list + 1;
+
+               /* one cell hole in the list = <>; */
+               if (!*phandle) {
+                       list++;
+                       goto next;
+               }
+
+               node = of_find_node_by_phandle(*phandle);
+               if (!node) {
+                       pr_debug("%s: could not find phandle\n",
+                                np->full_name);
+                       goto err0;
+               }
+
+               cells = of_get_property(node, cells_name, &size);
+               if (!cells || size != sizeof(*cells)) {
+                       pr_debug("%s: could not get %s for %s\n",
+                                np->full_name, cells_name, node->full_name);
+                       goto err1;
+               }
+
+               /* Next phandle is at offset of one phandle cell + #cells */
+               list += 1 + *cells;
+               if (list > list_end) {
+                       pr_debug("%s: insufficient arguments length\n",
+                                np->full_name);
+                       goto err1;
+               }
+next:
+               if (cur_index == index)
+                       break;
+
+               of_node_put(node);
+               node = NULL;
+               cur_index++;
+       }
+
+       if (!node) {
+               ret = -ENOENT;
+               goto err0;
+       }
+
+       *out_node = node;
+       *out_args = args;
+
+       return 0;
+err1:
+       of_node_put(node);
+err0:
+       pr_debug("%s failed with status %d\n", __func__, ret);
+       return ret;
+}
+EXPORT_SYMBOL(of_parse_phandles_with_args);

diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
index 1c9cab844f10aaa60cf80d9996b4782d0c1256e6..7cd7301b583992683391215816bd6bd277785691 100644 (file)
--- a/drivers/of/gpio.c
+++ b/drivers/of/gpio.c
@@ -28,78 +28,35 @@
  */
 int of_get_gpio(struct device_node *np, int index)
 {
-       int ret = -EINVAL;
+       int ret;
        struct device_node *gc;
        struct of_gpio_chip *of_gc = NULL;
        int size;
-       const u32 *gpios;
-       u32 nr_cells;
-       int i;
        const void *gpio_spec;
        const u32 *gpio_cells;
-       int gpio_index = 0;
 
-       gpios = of_get_property(np, "gpios", &size);
-       if (!gpios) {
-               ret = -ENOENT;
+       ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index,
+                                         &gc, &gpio_spec);
+       if (ret) {
+               pr_debug("%s: can't parse gpios property\n", __func__);
                goto err0;
        }
-       nr_cells = size / sizeof(u32);
-
-       for (i = 0; i < nr_cells; gpio_index++) {
-               const phandle *gpio_phandle;
-
-               gpio_phandle = gpios + i;
-               gpio_spec = gpio_phandle + 1;
-
-               /* one cell hole in the gpios = <>; */
-               if (!*gpio_phandle) {
-                       if (gpio_index == index)
-                               return -ENOENT;
-                       i++;
-                       continue;
-               }
-
-               gc = of_find_node_by_phandle(*gpio_phandle);
-               if (!gc) {
-                       pr_debug("%s: could not find phandle for gpios\n",
-                                np->full_name);
-                       goto err0;
-               }
-
-               of_gc = gc->data;
-               if (!of_gc) {
-                       pr_debug("%s: gpio controller %s isn't registered\n",
-                                np->full_name, gc->full_name);
-                       goto err1;
-               }
-
-               gpio_cells = of_get_property(gc, "#gpio-cells", &size);
-               if (!gpio_cells || size != sizeof(*gpio_cells) ||
-                               *gpio_cells != of_gc->gpio_cells) {
-                       pr_debug("%s: wrong #gpio-cells for %s\n",
-                                np->full_name, gc->full_name);
-                       goto err1;
-               }
-
-               /* Next phandle is at phandle cells + #gpio-cells */
-               i += sizeof(*gpio_phandle) / sizeof(u32) + *gpio_cells;
-               if (i >= nr_cells + 1) {
-                       pr_debug("%s: insufficient gpio-spec length\n",
-                                np->full_name);
-                       goto err1;
-               }
-
-               if (gpio_index == index)
-                       break;
-
-               of_gc = NULL;
-               of_node_put(gc);
-       }
 
+       of_gc = gc->data;
        if (!of_gc) {
-               ret = -ENOENT;
-               goto err0;
+               pr_debug("%s: gpio controller %s isn't registered\n",
+                        np->full_name, gc->full_name);
+               ret = -ENODEV;
+               goto err1;
+       }
+
+       gpio_cells = of_get_property(gc, "#gpio-cells", &size);
+       if (!gpio_cells || size != sizeof(*gpio_cells) ||
+                       *gpio_cells != of_gc->gpio_cells) {
+               pr_debug("%s: wrong #gpio-cells for %s\n",
+                        np->full_name, gc->full_name);
+               ret = -EINVAL;
+               goto err1;
        }
 
        ret = of_gc->xlate(of_gc, np, gpio_spec);

diff --git a/include/linux/of.h b/include/linux/of.h
index 79886ade070f2e791274c92814bc04bfbcff4947..e2488f5e7cb2bfc4ab275b1a2685bba103713205 100644 (file)
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -71,5 +71,8 @@ extern int of_n_size_cells(struct device_node *np);
 extern const struct of_device_id *of_match_node(
        const struct of_device_id *matches, const struct device_node *node);
 extern int of_modalias_node(struct device_node *node, char *modalias, int len);
+extern int of_parse_phandles_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);
 
 #endif /* _LINUX_OF_H */