dm: core: Provide ofnode_find_subnode_unit()

The ofnode_find_subnode() function currently processes things two
different ways, so the treatment of unit addresses differs depending on
whether OF_LIVE is enabled or not.

Add a new version which uses the ofnode API and add a test to check that
unit addresses can be matched correctly. Leave the old function in place
for the !OF_LIVE case, to avoid a code-size increase, e.g. on
firefly-rk3288

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/ofnode.c

@@ -599,14 +599,9 @@ ofnode ofnode_find_subnode(ofnode node, const char *subnode_name)
 	log_debug("%s: %s: ", __func__, subnode_name);
 
 	if (ofnode_is_np(node)) {
-		struct device_node *np = ofnode_to_np(node);
+		subnode = ofnode_find_subnode_unit(node, subnode_name);
-
-		for (np = np->child; np; np = np->sibling) {
-			if (!strcmp(subnode_name, np->name))
-				break;
-		}
-		subnode = np_to_ofnode(np);
 	} else {
+		/* special case to avoid code-size increase */
 		int ooffset = fdt_subnode_offset(ofnode_to_fdt(node),
 				ofnode_to_offset(node), subnode_name);
 		subnode = noffset_to_ofnode(node, ooffset);
@@ -617,6 +612,26 @@ ofnode ofnode_find_subnode(ofnode node, const char *subnode_name)
 	return subnode;
 }
 
+ofnode ofnode_find_subnode_unit(ofnode node, const char *subnode_name)
+{
+	ofnode subnode, found = ofnode_null();
+
+	assert(ofnode_valid(node));
+	log_debug("%s: ", subnode_name);
+
+	ofnode_for_each_subnode(subnode, node) {
+		if (ofnode_name_eq_unit(subnode, subnode_name)) {
+			found = subnode;
+			break;
+		}
+	}
+
+	log_debug("%s\n", ofnode_valid(found) ?
+		  ofnode_get_name(found) : "<none>");
+
+	return found;
+}
+
 int ofnode_read_u32_array(ofnode node, const char *propname,
 			  u32 *out_values, size_t sz)
 {

include/dm/ofnode.h

@@ -607,6 +607,18 @@ bool ofnode_read_bool(ofnode node, const char *propname);
  */
 ofnode ofnode_find_subnode(ofnode node, const char *subnode_name);
 
+/**
+ * ofnode_find_subnode_unit() - find a named subnode of a parent node
+ *
+ * @node:	valid reference to parent node
+ * @subnode_name: name of subnode to find, including any unit address. If the
+ *	unit address is omitted, any subnode which matches the name (excluding
+ *	any unit address) is returned
+ * Return: reference to subnode (which can be invalid if there is no such
+ * subnode)
+ */
+ofnode ofnode_find_subnode_unit(ofnode node, const char *subnode_name);
+
 #if CONFIG_IS_ENABLED(DM_INLINE_OFNODE)
 #include <asm/global_data.h>
 

test/dm/ofnode.c

@@ -1303,6 +1303,25 @@ static int dm_test_ofnode_find_subnode(struct unit_test_state *uts)
 }
 DM_TEST(dm_test_ofnode_find_subnode, UTF_SCAN_FDT);
 
+/* check ofnode_find_subnode() with unit addresses */
+static int dm_test_ofnode_find_subnode_unit(struct unit_test_state *uts)
+{
+	ofnode node, subnode;
+
+	node = ofnode_path("/some-bus");
+	ut_assert(ofnode_valid(node));
+	subnode = ofnode_find_subnode_unit(node, "c-test@5");
+	ut_assert(ofnode_valid(subnode));
+	ut_asserteq_str("c-test@5", ofnode_get_name(subnode));
+
+	subnode = ofnode_find_subnode_unit(node, "c-test");
+	ut_assert(ofnode_valid(subnode));
+	ut_asserteq_str("c-test@5", ofnode_get_name(subnode));
+
+	return 0;
+}
+DM_TEST(dm_test_ofnode_find_subnode_unit, UTF_SCAN_FDT);
+
 /* test ofnode_find_subnode() on the 'other' tree */
 static int dm_test_ofnode_find_subnode_ot(struct unit_test_state *uts)
 {