1Qualcomm Always-On Subsystem side channel binding
2
3This binding describes the hardware component responsible for side channel
4requests to the always-on subsystem (AOSS), used for certain power management
5requests that is not handled by the standard RPMh interface. Each client in the
6SoC has it's own block of message RAM and IRQ for communication with the AOSS.
7The protocol used to communicate in the message RAM is known as Qualcomm
8Messaging Protocol (QMP)
9
10The AOSS side channel exposes control over a set of resources, used to control
11a set of debug related clocks and to affect the low power state of resources
12related to the secondary subsystems. These resources are exposed as a set of
13power-domains.
14
15- compatible:
16	Usage: required
17	Value type: <string>
18	Definition: must be one of:
19		    "qcom,sc7180-aoss-qmp"
20		    "qcom,sdm845-aoss-qmp"
21		    "qcom,sm8150-aoss-qmp"
22
23- reg:
24	Usage: required
25	Value type: <prop-encoded-array>
26	Definition: the base address and size of the message RAM for this
27		    client's communication with the AOSS
28
29- interrupts:
30	Usage: required
31	Value type: <prop-encoded-array>
32	Definition: should specify the AOSS message IRQ for this client
33
34- mboxes:
35	Usage: required
36	Value type: <prop-encoded-array>
37	Definition: reference to the mailbox representing the outgoing doorbell
38		    in APCS for this client, as described in mailbox/mailbox.txt
39
40- #clock-cells:
41	Usage: optional
42	Value type: <u32>
43	Definition: must be 0
44		    The single clock represents the QDSS clock.
45
46- #power-domain-cells:
47	Usage: optional
48	Value type: <u32>
49	Definition: must be 1
50		    The provided power-domains are:
51		    CDSP state (0), LPASS state (1), modem state (2), SLPI
52		    state (3), SPSS state (4) and Venus state (5).
53
54= SUBNODES
55The AOSS side channel also provides the controls for three cooling devices,
56these are expressed as subnodes of the QMP node. The name of the node is used
57to identify the resource and must therefor be "cx", "mx" or "ebi".
58
59- #cooling-cells:
60	Usage: optional
61	Value type: <u32>
62	Definition: must be 2
63
64= EXAMPLE
65
66The following example represents the AOSS side-channel message RAM and the
67mechanism exposing the power-domains, as found in SDM845.
68
69  aoss_qmp: qmp@c300000 {
70	  compatible = "qcom,sdm845-aoss-qmp";
71	  reg = <0x0c300000 0x100000>;
72	  interrupts = <GIC_SPI 389 IRQ_TYPE_EDGE_RISING>;
73	  mboxes = <&apss_shared 0>;
74
75	  #power-domain-cells = <1>;
76
77	  cx_cdev: cx {
78		#cooling-cells = <2>;
79	  };
80
81	  mx_cdev: mx {
82		#cooling-cells = <2>;
83	  };
84  };
85