From befc8236a74feb912e5f02ae6764f5400297b2d6 Mon Sep 17 00:00:00 2001
From: Joseph Lo <josephl@nvidia.com>
Date: Thu, 9 Apr 2020 19:52:32 +0200
Subject: [PATCH] dt-bindings: memory: tegra: Add external memory controller
 binding for Tegra210

Add the binding document for the external memory controller (EMC) which
communicates with external LPDDR4 devices. It includes the bindings of
the EMC node and a sub-node of EMC table which under the reserved memory
node. The EMC table contains the data of the rates that EMC supported.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Rob Herring <robh@kernel.org>
---
 .../nvidia,tegra210-emc.yaml                  | 82 +++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.yaml

diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.yaml b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.yaml
new file mode 100644
index 000000000000..49ab09252e52
--- /dev/null
+++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.yaml
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/nvidia,tegra210-emc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra210 SoC External Memory Controller
+
+maintainers:
+  - Thierry Reding <thierry.reding@gmail.com>
+  - Jon Hunter <jonathanh@nvidia.com>
+
+description: |
+  The EMC interfaces with the off-chip SDRAM to service the request stream
+  sent from the memory controller.
+
+properties:
+  compatible:
+    const: nvidia,tegra210-emc
+
+  reg:
+    maxItems: 3
+
+  clocks:
+    items:
+      - description: external memory clock
+
+  clock-names:
+    items:
+      - const: emc
+
+  interrupts:
+    items:
+      - description: EMC general interrupt
+
+  memory-region:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      phandle to a reserved memory region describing the table of EMC
+      frequencies trained by the firmware
+
+  nvidia,memory-controller:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      phandle of the memory controller node
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - nvidia,memory-controller
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/tegra210-car.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    reserved-memory {
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges;
+
+        emc_table: emc-table@83400000 {
+            compatible = "nvidia,tegra210-emc-table";
+            reg = <0x83400000 0x10000>;
+        };
+    };
+
+    external-memory-controller@7001b000 {
+        compatible = "nvidia,tegra210-emc";
+        reg = <0x7001b000 0x1000>,
+              <0x7001e000 0x1000>,
+              <0x7001f000 0x1000>;
+        clocks = <&tegra_car TEGRA210_CLK_EMC>;
+        clock-names = "emc";
+        interrupts = <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>;
+        memory-region = <&emc_table>;
+        nvidia,memory-controller = <&mc>;
+    };