Texas Instruments' K3 AM654 DDRSS
=================================

K3 based AM654 devices has DDR memory subsystem that comprises
Synopys DDR controller, Synopsis DDR phy and wrapper logic to
integrate these blocks into the device. This DDR subsystem
provides an interface to external SDRAM devices. This DDRSS driver
adds support for the initialization of the external SDRAM devices by
configuring the DDRSS registers and using the buitin PHY
initialization routines.

DDRSS device node:
==================
Required properties:
--------------------
- compatible:		Shall be: "ti,am654-ddrss"
- reg-names 		ss - Map the sub system wrapper logic region
			ctl - Map the controller region
			phy - Map the PHY region
- reg:			Contains the register map per reg-names.
- power-domains:	Should contain a phandle to a PM domain provider node
			and an args specifier containing the DDRSS device id
			value. This property is as per the binding,
			doc/device-tree-bindings/power/ti,sci-pm-domain.txt
- clocks:		Must contain an entry for enabling DDR clock. Should
			be defined as per the appropriate clock bindings consumer
			usage in doc/device-tree-bindings/clock/ti,sci-clk.txt


Optional Properties:
--------------------
- clock-frequency:	Frequency at which DDR pll should be locked.
			If not provided, default frequency will be used.

Example (AM65x):
================
		memory-controller: memory-controller@298e000 {
			compatible = "ti,am654-ddrss";
			reg = <0x0298e000 0x200>,
				<0x02980000 0x4000>,
				<0x02988000 0x2000>;
			reg-names = "ss", "ctl", "phy";
			clocks = <&k3_clks 20 0>;
			power-domains = <&k3_pds 20>;
			u-boot,dm-spl;
		};
