1 files changed, 114 insertions, 20 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index a7264644003f..7c79e94a35ea 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -420,13 +420,12 @@ static struct of_modalias_table of_modalias_table[] = {
  * @len:        Length of modalias value
  *
  * Based on the value of the compatible property, this routine will determine
- * an appropriate modalias value for a particular device tree node.  Three
- * separate methods are used to derive a modalias value.
+ * an appropriate modalias value for a particular device tree node.  Two
+ * separate methods are attempted to derive a modalias value.
  *
  * First method is to lookup the compatible value in of_modalias_table.
- * Second is to look for a "linux,<modalias>" entry in the compatible list
- * and used that for modalias.  Third is to strip off the manufacturer
- * prefix from the first compatible entry and use the remainder as modalias
+ * Second is to strip off the manufacturer prefix from the first
+ * compatible entry and use the remainder as modalias
  *
  * This routine returns 0 on success
  */
@@ -449,21 +448,7 @@ int of_modalias_node(struct device_node *node, char *modalias, int len)
         if (!compatible)
                 return -ENODEV;
 
-        /* 2. search for linux,<modalias> entry */
-        p = compatible;
-        while (cplen > 0) {
-                if (!strncmp(p, "linux,", 6)) {
-                        p += 6;
-                        strlcpy(modalias, p, len);
-                        return 0;
-                }
-
-                i = strlen(p) + 1;
-                p += i;
-                cplen -= i;
-        }
-
-        /* 3. take first compatible entry and strip manufacturer */
+        /* 2. take first compatible entry and strip manufacturer */
         p = strchr(compatible, ',');
         if (!p)
                 return -ENODEV;
@@ -473,3 +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);