drivers: regulator: fix getting gpio for level control

Swap the 2 calls to find gpio property in "regulator-gpio" compatible
node. The call that expects to get a TEE_ERROR_ITEM_NOT_FOUND return
value (as described in the inline comment) for an unsupported 2nd level
control GPIO can fail with TEE_ERROR_DEFER_DRIVER_INIT return value
when the 1st GPIO phandle listed in the 'gpios' DT node property relates
to a GPIO driver that is not yet probed. Fix that by first getting the
required GPIO control level and then testing presence of other GPIO
phandle in the 'gpios' DT property.

Fixes: f164f0f ("drivers: regulator: GPIO controlled regulator")
Reviewed-by: Gatien Chevallier <[email protected]>
Signed-off-by: Etienne Carriere <[email protected]>

core/drivers/regulator/regulator_gpio.c

@@ -148,6 +148,11 @@ static TEE_Result get_voltage_level_gpio(const void *fdt, int node,
 	void *gpio_ref = &gpio;
 	int len = 0;
 
+	res = dt_driver_device_from_node_idx_prop("gpios", fdt, node, 0,
+						  DT_DRIVER_GPIO, gpio_ref);
+	if (res)
+		return res;
+
 	/*
 	 * DT bindings allows more than 1 GPIO to control more than
 	 * 2 voltage levels. As it's not used so far in known platforms
@@ -161,11 +166,6 @@ static TEE_Result get_voltage_level_gpio(const void *fdt, int node,
 		return TEE_ERROR_GENERIC;
 	}
 
-	res = dt_driver_device_from_node_idx_prop("gpios", fdt, node, 0,
-						  DT_DRIVER_GPIO, gpio_ref);
-	if (res)
-		return res;
-
 	cuint = fdt_getprop(fdt, node, "states", &len);
 	if (!cuint || len != 4 * sizeof(fdt32_t)) {
 		EMSG("Node %s expects 2 levels from property \"states\"",