Add device tree binding documentation for the Qualcomm Shared Memory Device, used for communication between the various CPUs in the Qualcomm SoCs. Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx> --- No changes since v2 .../devicetree/bindings/soc/qcom/qcom,smd.txt | 79 ++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 Documentation/devicetree/bindings/soc/qcom/qcom,smd.txt diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smd.txt b/Documentation/devicetree/bindings/soc/qcom/qcom,smd.txt new file mode 100644 index 000000000000..f65c76db9859 --- /dev/null +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smd.txt @@ -0,0 +1,79 @@ +Qualcomm Shared Memory Driver (SMD) binding + +This binding describes the Qualcomm Shared Memory Driver, a fifo based +communication channel for sending data between the various subsystems in +Qualcomm platforms. + +- compatible: + Usage: required + Value type: <stringlist> + Definition: must be "qcom,smd" + += EDGES + +Each subnode of the SMD node represents a remote subsystem or a remote +processor of some sort - or in SMD language an "edge". The name of the edges +are not important. +The edge is described by the following properties: + +- interrupts: + Usage: required + Value type: <prop-encoded-array> + Definition: should specify the IRQ used by the remote processor to + signal this processor about communication related updates + +- qcom,ipc: + Usage: required + Value type: <prop-encoded-array> + Definition: three entries specifying the outgoing ipc bit used for + signaling the remote processor: + - phandle to a syscon node representing the apcs registers + - u32 representing offset to the register within the syscon + - u32 representing the ipc bit within the register + +- qcom,smd-edge: + Usage: required + Value type: <u32> + Definition: the identifier of the remote processor in the smd channel + allocation table + += SMD DEVICES + +In turn, subnodes of the "edges" represent devices tied to SMD channels on that +"edge". The names of the devices are not important. The properties of these +nodes are defined by the individual bindings for the SMD devices - but must +contain the following property: + +- qcom,smd-channels: + Usage: required + Value type: <stringlist> + Definition: a list of channels tied to this device, used for matching + the device to channels + += EXAMPLE + +The following example represents a smd node, with one edge representing the +"rpm" subsystem. For the "rpm" subsystem we have a device tied to the +"rpm_request" channel. + + apcs: syscon@f9011000 { + compatible = "syscon"; + reg = <0xf9011000 0x1000>; + }; + + smd { + compatible = "qcom,smd"; + + rpm { + interrupts = <0 168 1>; + qcom,ipc = <&apcs 8 0>; + qcom,smd-edge = <15>; + + rpm_requests { + compatible = "qcom,rpm-msm8974"; + qcom,smd-channels = "rpm_requests"; + + ... + }; + }; + }; -- 1.8.2.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html