HSI: Add common DT binding for HSI client devices

Implement and document generic DT bindings for HSI clients.

Signed-off-by: Sebastian Reichel <sre@kernel.org>

1 files changed, 44 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/hsi/client-devices.txt b/Documentation/devicetree/bindings/hsi/client-devices.txt
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+Each HSI port is supposed to have one child node, which
+symbols the remote device connected to the HSI port. The
+following properties are standardized for HSI clients:
+
+Required HSI configuration properties:
+
+- reg:			A list of channel ids
+
+- hsi-rx-mode:		Receiver Bit transmission mode ("stream" or "frame")
+- hsi-tx-mode:		Transmitter Bit transmission mode ("stream" or "frame")
+- hsi-mode:		May be used instead hsi-rx-mode and hsi-tx-mode if
+			the transmission mode is the same for receiver and
+			transmitter
+- hsi-speed-kbps:	Max bit transmission speed in kbit/s
+- hsi-flow:		RX flow type ("synchronized" or "pipeline")
+- hsi-arb-mode:		Arbitration mode for TX frame ("round-robin", "priority")
+
+Optional HSI configuration properties:
+
+- reg-names:		A list with one name per channel specified in the
+			reg property
+
+
+Device Tree node example for an HSI client:
+
+hsi-controller {
+	hsi-port {
+		modem: hsi-client {
+			compatible = "nokia,n900-modem";
+
+			reg = <0>, <1>, <2>, <3>;
+			reg-names = "mcsaab-control",
+				    "speech-control",
+				    "speech-data",
+				    "mcsaab-data";
+			hsi-speed-kbps = <55000>;
+			hsi-mode = "frame";
+			hsi-flow = "synchronized";
+			hsi-arb-mode = "round-robin";
+
+			/* more client specific properties */
+		};
+	};
+};