regulator: gpio-regulator: do not open-code counting and access of dt array elements

Open coding the counting of elements in a dt-property is abstracted by the newly
introduced of_property_count_uXX_elems functions. Additionally the raw iteration
over the states element exposes the endian conversion and dtb-format details,
which according to Mark Rutland "would be nice to limit [...] to of_ helper
functions".

Thus change gpio-regulator to use the helper for element counting and
of_property_read_u32_index for retrieval of individual values.

This makes it possible to remove the raw access to the states property entirely.
Signed-off-by: Heiko Stuebner <heiko.stuebner@bqreaders.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/regulator/gpio-regulator.c

@@ -136,7 +136,6 @@ static struct gpio_regulator_config *
 of_get_gpio_regulator_config(struct device *dev, struct device_node *np)
 {
 	struct gpio_regulator_config *config;
-	struct property *prop;
 	const char *regtype;
 	int proplen, gpio, i;
 	int ret;
@@ -191,14 +190,12 @@ of_get_gpio_regulator_config(struct device *dev, struct device_node *np)
 	}
 
 	/* Fetch states. */
-	prop = of_find_property(np, "states", NULL);
-	if (!prop) {
+	proplen = of_property_count_u32_elems(np, "states");
+	if (proplen < 0) {
 		dev_err(dev, "No 'states' property found\n");
 		return ERR_PTR(-EINVAL);
 	}
 
-	proplen = prop->length / sizeof(int);
-
 	config->states = devm_kzalloc(dev,
 				sizeof(struct gpio_regulator_state)
 				* (proplen / 2),
@@ -207,10 +204,10 @@ of_get_gpio_regulator_config(struct device *dev, struct device_node *np)
 		return ERR_PTR(-ENOMEM);
 
 	for (i = 0; i < proplen / 2; i++) {
-		config->states[i].value =
-			be32_to_cpup((int *)prop->value + (i * 2));
-		config->states[i].gpios =
-			be32_to_cpup((int *)prop->value + (i * 2 + 1));
+		of_property_read_u32_index(np, "states", i * 2,
+					   &config->states[i].value);
+		of_property_read_u32_index(np, "states", i * 2 + 1,
+					   &config->states[i].gpios);
 	}
 	config->nr_states = i;