regulator: core: make regulator_register() EPROBE_DEFER aware

Sometimes it can happen that the regulator_of_get_init_data() can't
retrieve the config due to a not probed device the regulator depends on.
Fix that by checking the return value of of_parse_cb() and return
EPROBE_DEFER in such cases.
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Link: https://lore.kernel.org/r/20190917154021.14693-4-m.felsch@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/core.c

@@ -5053,6 +5053,19 @@ regulator_register(const struct regulator_desc *regulator_desc,
 
 	init_data = regulator_of_get_init_data(dev, regulator_desc, config,
 					       &rdev->dev.of_node);
+
+	/*
+	 * Sometimes not all resources are probed already so we need to take
+	 * that into account. This happens most the time if the ena_gpiod comes
+	 * from a gpio extender or something else.
+	 */
+	if (PTR_ERR(init_data) == -EPROBE_DEFER) {
+		kfree(config);
+		kfree(rdev);
+		ret = -EPROBE_DEFER;
+		goto rinse;
+	}
+
 	/*
 	 * We need to keep track of any GPIO descriptor coming from the
 	 * device tree until we have handled it over to the core. If the

drivers/regulator/of_regulator.c

@@ -445,11 +445,20 @@ struct regulator_init_data *regulator_of_get_init_data(struct device *dev,
 		goto error;
 	}
 
-	if (desc->of_parse_cb && desc->of_parse_cb(child, desc, config)) {
-		dev_err(dev,
-			"driver callback failed to parse DT for regulator %pOFn\n",
-			child);
-		goto error;
+	if (desc->of_parse_cb) {
+		int ret;
+
+		ret = desc->of_parse_cb(child, desc, config);
+		if (ret) {
+			if (ret == -EPROBE_DEFER) {
+				of_node_put(child);
+				return ERR_PTR(-EPROBE_DEFER);
+			}
+			dev_err(dev,
+				"driver callback failed to parse DT for regulator %pOFn\n",
+				child);
+			goto error;
+		}
 	}
 
 	*node = child;