power: domain: add dev_power_domain_on

Add this new API to power on multiple domains attached
to a device.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Changed to static inline and added a condition into C file:
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/power/domain/power-domain-uclass.c b/drivers/power/domain/power-domain-uclass.c
index 2ea0ff2..c961436 100644
--- a/drivers/power/domain/power-domain-uclass.c
+++ b/drivers/power/domain/power-domain-uclass.c
@@ -107,6 +107,27 @@
 	return ops->off(power_domain);
 }
 
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+int dev_power_domain_on(struct udevice *dev)
+{
+	struct power_domain pd;
+	int i, count, ret;
+
+	count = dev_count_phandle_with_args(dev, "power-domains",
+					    "#power-domain-cells");
+	for (i = 0; i < count; i++) {
+		ret = power_domain_get_by_index(dev, &pd, i);
+		if (ret)
+			return ret;
+		ret = power_domain_on(&pd);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+#endif
+
 UCLASS_DRIVER(power_domain) = {
 	.id		= UCLASS_POWER_DOMAIN,
 	.name		= "power_domain",