regulator: core: add of_match_full_name boolean flag

During regulators registration, if .of_match and .regulators_node are
defined as non-null strings in struct regulator_desc the core searches the
DT subtree rooted at .regulators_node trying to match, at first, .of_match
against the 'regulator-compatible' property and, then, falling back to use
the name of the node itself to determine a good match.

Property 'regulator-compatible', though, is now deprecated and falling back
to match against the node name, works fine only as long as the involved
nodes are named in an unique way across the searched subtree; if that's not
the case, like when using <common-name>@<unit> style naming for properties
indexed via 'reg' property (as advised by the standard), the above matching
mechanism based on the simple common name will lead to multiple matches and
the only viable alternative would be to properly define the now deprecated
'regulator-compatible' as the node full name, i.e. <common-name>@<unit>.

In order to address this case without using such deprecated binding, define
a new boolean flag .of_match_full_name in struct regulator_desc to force
the core to match against the node full-name instead of the plain name.

Signed-off-by: Cristian Marussi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/of_regulator.c

···
 
 	for_each_available_child_of_node(search, child) {
 		name = of_get_property(child, "regulator-compatible", NULL);
-		if (!name)
-			name = child->name;
+		if (!name) {
+			if (!desc->of_match_full_name)
+				name = child->name;
+			else
+				name = child->full_name;
+		}
 
 		if (!strcmp(desc->of_match, name)) {
 			of_node_put(search);

include/linux/regulator/driver.h

···
  * @name: Identifying name for the regulator.
  * @supply_name: Identifying the regulator supply
  * @of_match: Name used to identify regulator in DT.
+ * @of_match_full_name: A flag to indicate that the of_match string, if
+ *			present, should be matched against the node full_name.
  * @regulators_node: Name of node containing regulator definitions in DT.
  * @of_parse_cb: Optional callback called only if of_match is present.
  *               Will be called for each regulator parsed from DT, during
···
 	const char *name;
 	const char *supply_name;
 	const char *of_match;
+	bool of_match_full_name;
 	const char *regulators_node;
 	int (*of_parse_cb)(struct device_node *,
 			    const struct regulator_desc *,