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diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,aoss-qmp.txt b/Documentation/devicetree/bindings/soc/qcom/qcom,aoss-qmp.txt new file mode 100644 index 000000000000..954ffee0a9c4 --- /dev/null +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,aoss-qmp.txt @@ -0,0 +1,81 @@ +Qualcomm Always-On Subsystem side channel binding + +This binding describes the hardware component responsible for side channel +requests to the always-on subsystem (AOSS), used for certain power management +requests that is not handled by the standard RPMh interface. Each client in the +SoC has it's own block of message RAM and IRQ for communication with the AOSS. +The protocol used to communicate in the message RAM is known as Qualcomm +Messaging Protocol (QMP) + +The AOSS side channel exposes control over a set of resources, used to control +a set of debug related clocks and to affect the low power state of resources +related to the secondary subsystems. These resources are exposed as a set of +power-domains. + +- compatible: + Usage: required + Value type: <string> + Definition: must be "qcom,sdm845-aoss-qmp" + +- reg: + Usage: required + Value type: <prop-encoded-array> + Definition: the base address and size of the message RAM for this + client's communication with the AOSS + +- interrupts: + Usage: required + Value type: <prop-encoded-array> + Definition: should specify the AOSS message IRQ for this client + +- mboxes: + Usage: required + Value type: <prop-encoded-array> + Definition: reference to the mailbox representing the outgoing doorbell + in APCS for this client, as described in mailbox/mailbox.txt + +- #clock-cells: + Usage: optional + Value type: <u32> + Definition: must be 0 + The single clock represents the QDSS clock. + +- #power-domain-cells: + Usage: optional + Value type: <u32> + Definition: must be 1 + The provided power-domains are: + CDSP state (0), LPASS state (1), modem state (2), SLPI + state (3), SPSS state (4) and Venus state (5). + += SUBNODES +The AOSS side channel also provides the controls for three cooling devices, +these are expressed as subnodes of the QMP node. The name of the node is used +to identify the resource and must therefor be "cx", "mx" or "ebi". + +- #cooling-cells: + Usage: optional + Value type: <u32> + Definition: must be 2 + += EXAMPLE + +The following example represents the AOSS side-channel message RAM and the +mechanism exposing the power-domains, as found in SDM845. + + aoss_qmp: qmp@c300000 { + compatible = "qcom,sdm845-aoss-qmp"; + reg = <0x0c300000 0x100000>; + interrupts = <GIC_SPI 389 IRQ_TYPE_EDGE_RISING>; + mboxes = <&apss_shared 0>; + + #power-domain-cells = <1>; + + cx_cdev: cx { + #cooling-cells = <2>; + }; + + mx_cdev: mx { + #cooling-cells = <2>; + }; + }; |