| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | SPM AVS Wrapper 2 (SAW2) |
| 2 | |
| 3 | The SAW2 is a wrapper around the Subsystem Power Manager (SPM) and the |
| 4 | Adaptive Voltage Scaling (AVS) hardware. The SPM is a programmable |
| 5 | power-controller that transitions a piece of hardware (like a processor or |
| 6 | subsystem) into and out of low power modes via a direct connection to |
| 7 | the PMIC. It can also be wired up to interact with other processors in the |
| 8 | system, notifying them when a low power state is entered or exited. |
| 9 | |
| 10 | Multiple revisions of the SAW hardware are supported using these Device Nodes. |
| 11 | SAW2 revisions differ in the register offset and configuration data. Also, the |
| 12 | same revision of the SAW in different SoCs may have different configuration |
| 13 | data due the differences in hardware capabilities. Hence the SoC name, the |
| 14 | version of the SAW hardware in that SoC and the distinction between cpu (big |
| 15 | or Little) or cache, may be needed to uniquely identify the SAW register |
| 16 | configuration and initialization data. The compatible string is used to |
| 17 | indicate this parameter. |
| 18 | |
| 19 | PROPERTIES |
| 20 | |
| 21 | - compatible: |
| 22 | Usage: required |
| 23 | Value type: <string> |
| 24 | Definition: Must have |
| 25 | "qcom,saw2" |
| 26 | A more specific value could be one of: |
| 27 | "qcom,apq8064-saw2-v1.1-cpu" |
| 28 | "qcom,msm8226-saw2-v2.1-cpu" |
| 29 | "qcom,msm8974-saw2-v2.1-cpu" |
| 30 | "qcom,apq8084-saw2-v2.1-cpu" |
| 31 | |
| 32 | - reg: |
| 33 | Usage: required |
| 34 | Value type: <prop-encoded-array> |
| 35 | Definition: the first element specifies the base address and size of |
| 36 | the register region. An optional second element specifies |
| 37 | the base address and size of the alias register region. |
| 38 | |
| 39 | - regulator: |
| 40 | Usage: optional |
| 41 | Value type: boolean |
| 42 | Definition: Indicates that this SPM device acts as a regulator device |
| 43 | device for the core (CPU or Cache) the SPM is attached |
| 44 | to. |
| 45 | |
| 46 | Example 1: |
| 47 | |
| 48 | power-controller@2099000 { |
| 49 | compatible = "qcom,saw2"; |
| 50 | reg = <0x02099000 0x1000>, <0x02009000 0x1000>; |
| 51 | regulator; |
| 52 | }; |
| 53 | |
| 54 | Example 2: |
| 55 | saw0: power-controller@f9089000 { |
| 56 | compatible = "qcom,apq8084-saw2-v2.1-cpu", "qcom,saw2"; |
| 57 | reg = <0xf9089000 0x1000>, <0xf9009000 0x1000>; |
| 58 | }; |