firmware: ti_sci: Add support to get TISCI handle using of_phandle

TISCI has been updated to have support for Resource management(like
interrupts etc..). And there can be multiple device instances of a
resource type in a SoC. So every driver corresponding to a resource type
should get a TISCI handle so that it can make TISCI calls. And each
DT node corresponding to a device should exist under its corresponding
bus node as per the SoC architecture.

But existing apis in TISCI library assumes that all TISCI users are
child nodes of TISCI. Which is not true in the above case. So introduce
(devm_)ti_sci_get_by_phandle() apis that can be used by TISCI users
to get TISCI handle using of phandle property.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

include/linux/soc/ti/ti_sci_protocol.h

@@ -217,6 +217,10 @@ struct ti_sci_handle {
 const struct ti_sci_handle *ti_sci_get_handle(struct device *dev);
 int ti_sci_put_handle(const struct ti_sci_handle *handle);
 const struct ti_sci_handle *devm_ti_sci_get_handle(struct device *dev);
+const struct ti_sci_handle *ti_sci_get_by_phandle(struct device_node *np,
+						  const char *property);
+const struct ti_sci_handle *devm_ti_sci_get_by_phandle(struct device *dev,
+						       const char *property);
 
 #else	/* CONFIG_TI_SCI_PROTOCOL */
 
@@ -236,6 +240,19 @@ const struct ti_sci_handle *devm_ti_sci_get_handle(struct device *dev)
 	return ERR_PTR(-EINVAL);
 }
 
+static inline
+const struct ti_sci_handle *ti_sci_get_by_phandle(struct device_node *np,
+						  const char *property)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline
+const struct ti_sci_handle *devm_ti_sci_get_by_phandle(struct device *dev,
+						       const char *property)
+{
+	return ERR_PTR(-EINVAL);
+}
 #endif	/* CONFIG_TI_SCI_PROTOCOL */
 
 #endif	/* __TISCI_PROTOCOL_H */