dt-bindings: Add SLIMbus bindings

SLIMbus (Serial Low Power Interchip Media Bus) is a specification
developed by MIPI (Mobile Industry Processor Interface) alliance.
SLIMbus is a 2-wire implementation, which is used to communicate with
peripheral components like audio-codec.

This patch adds device tree bindings for the slimbus.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviwed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/slimbus/bus.txt b/Documentation/devicetree/bindings/slimbus/bus.txt
new file mode 100644 (file)
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+++ b/Documentation/devicetree/bindings/slimbus/bus.txt
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+SLIM(Serial Low Power Interchip Media Bus) bus
+
+SLIMbus is a 2-wire bus, and is used to communicate with peripheral
+components like audio-codec.
+
+Required property for SLIMbus controller node:
+- compatible   - name of SLIMbus controller
+
+Child nodes:
+Every SLIMbus controller node can contain zero or more child nodes
+representing slave devices on the bus. Every SLIMbus slave device is
+uniquely determined by the enumeration address containing 4 fields:
+Manufacturer ID, Product code, Device index, and Instance value for
+the device.
+If child node is not present and it is instantiated after device
+discovery (slave device reporting itself present).
+
+In some cases it may be necessary to describe non-probeable device
+details such as non-standard ways of powering up a device. In
+such cases, child nodes for those devices will be present as
+slaves of the SLIMbus controller, as detailed below.
+
+Required property for SLIMbus child node if it is present:
+- reg          - Should be ('Device index', 'Instance ID') from SLIMbus
+                 Enumeration  Address.
+                 Device Index Uniquely identifies multiple Devices within
+                 a single Component.
+                 Instance ID Is for the cases where multiple Devices of the
+                 same type or Class are attached to the bus.
+
+- compatible   -"slimMID,PID". The textual representation of Manufacturer ID,
+                 Product Code, shall be in lower case hexadecimal with leading
+                 zeroes suppressed
+
+SLIMbus example for Qualcomm's slimbus manager component:
+
+       slim@28080000 {
+               compatible = "qcom,apq8064-slim", "qcom,slim";
+               reg = <0x28080000 0x2000>,
+               interrupts = <0 33 0>;
+               clocks = <&lcc SLIMBUS_SRC>, <&lcc AUDIO_SLIMBUS_CLK>;
+               clock-names = "iface", "core";
+               #address-cells = <2>;
+               #size-cell = <0>;
+
+               codec: wcd9310@1,0{
+                       compatible = "slim217,60";
+                       reg = <1 0>;
+               };
+       };