ram: Introduce K3 AM654 DDR Sub System driver

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

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Schuyler Patton <spatton@ti.com>
Signed-off-by: James Doublesin <doublesin@ti.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/ram/k3-am654-ddrss.txt b/doc/device-tree-bindings/ram/k3-am654-ddrss.txt
new file mode 100644
index 0000000000..4ed731c524
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+++ b/doc/device-tree-bindings/ram/k3-am654-ddrss.txt
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+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;
+		};