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+NVIDIA Tegra Combined UART (TCU)
+
+The TCU is a system for sharing a hardware UART instance among multiple
+systems within the Tegra SoC. It is implemented through a mailbox-
+based protocol where each "virtual UART" has a pair of mailboxes, one
+for transmitting and one for receiving, that is used to communicate
+with the hardware implementing the TCU.
+
+Required properties:
+- name : Should be tcu
+- compatible
+    Array of strings
+    One of:
+    - "nvidia,tegra194-tcu"
+- mbox-names:
+    "rx" - Mailbox for receiving data from hardware UART
+    "tx" - Mailbox for transmitting data to hardware UART
+- mboxes: Mailboxes corresponding to the mbox-names.
+
+This node is a mailbox consumer. See the following files for details of
+the mailbox subsystem, and the specifiers implemented by the relevant
+provider(s):
+
+- .../mailbox/mailbox.txt
+- .../mailbox/nvidia,tegra186-hsp.txt
+
+Example bindings:
+-----------------
+
+tcu: tcu {
+	compatible = "nvidia,tegra194-tcu";
+	mboxes = <&hsp_top0 TEGRA_HSP_MBOX_TYPE_SM 0>,
+	         <&hsp_aon TEGRA_HSP_MBOX_TYPE_SM 1>;
+	mbox-names = "rx", "tx";
+};