dt-bindings: soc: qcom: merge qcom,saw2.txt into qcom,spm.yaml

The Qualcomm SPM / SAW2 device is described in two bindigns files:
arm/msm/qcom,saw2.txt and soc/qcom/qcom,spm.yaml. Merge the former into
the latter, adding detailed device node description. While we are at it,
also rename qcom,spm.yaml to qcom,saw2.yaml to follow the actual
compatible used for these devices.

The regulator property is retained as is. It will be changed in the
later patches.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20240102-saw2-spm-regulator-v7-1-0472ec237f49@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: lumag

Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt

@@ -1,18 +1,25 @@
 # SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
 %YAML 1.2
 ---
-$id: http://devicetree.org/schemas/soc/qcom/qcom,spm.yaml#
+$id: http://devicetree.org/schemas/soc/qcom/qcom,saw2.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Qualcomm Subsystem Power Manager
+title: Qualcomm Subsystem Power Manager / SPM AVS Wrapper 2 (SAW2)
 
 maintainers:
   - Andy Gross <agross@kernel.org>
   - Bjorn Andersson <bjorn.andersson@linaro.org>
 
 description: |
-  This binding describes the Qualcomm Subsystem Power Manager, used to control
-  the peripheral logic surrounding the application cores in Qualcomm platforms.
+  The Qualcomm Subsystem Power Manager is used to control the peripheral logic
+  surrounding the application cores in Qualcomm platforms.
+
+  The SAW2 is a wrapper around the Subsystem Power Manager (SPM) and the
+  Adaptive Voltage Scaling (AVS) hardware. The SPM is a programmable
+  power-controller that transitions a piece of hardware (like a processor or
+  subsystem) into and out of low power modes via a direct connection to
+  the PMIC. It can also be wired up to interact with other processors in the
+  system, notifying them when a low power state is entered or exited.
 
 properties:
   compatible:
@@ -34,8 +41,15 @@ properties:
       - const: qcom,saw2
 
   reg:
-    description: Base address and size of the SPM register region
-    maxItems: 1
+    items:
+      - description: Base address and size of the SPM register region
+      - description: Base address and size of the alias register region
+    minItems: 1
+
+  regulator:
+    type: boolean
+    description: Indicates that this SPM device acts as a regulator device
+      device for the core (CPU or Cache) the SPM is attached to.
 
 required:
   - compatible