[PATCH v14 1/7] dt-bindings: arm: Add support for Qualcomm TGU trace

[Songwei Chai <songwei.chai@oss.qualcomm.com>]

The Trigger Generation Unit (TGU) is designed to detect patterns or
sequences within a specific region of the System on Chip (SoC). Once
configured and activated, it monitors sense inputs and can detect a
pre-programmed state or sequence across clock cycles, subsequently
producing a trigger.

   TGU configuration space
        offset table
 x-------------------------x
 |                         |
 |                         |
 |                         |                           Step configuration
 |                         |                             space layout
 |   coresight management  |                           x-------------x
 |        registers        |                     |---> |             |
 |                         |                     |     |  reserve    |
 |                         |                     |     |             |
 |-------------------------|                     |     |-------------|
 |                         |                     |     | priority[3] |
 |         step[7]         |<--                  |     |-------------|
 |-------------------------|   |                 |     | priority[2] |
 |                         |   |                 |     |-------------|
 |           ...           |   |Steps region     |     | priority[1] |
 |                         |   |                 |     |-------------|
 |-------------------------|   |                 |     | priority[0] |
 |                         |<--                  |     |-------------|
 |         step[0]         |-------------------->      |             |
 |-------------------------|                           |  condition  |
 |                         |                           |             |
 |     control and status  |                           x-------------x
 |           space         |                           |             |
 x-------------------------x                           |Timer/Counter|
                                                       |             |
						       x-------------x
TGU Configuration in Hardware

The TGU provides a step region for user configuration, similar
to a flow chart. Each step region consists of three register clusters:

1.Priority Region: Sets the required signals with priority.
2.Condition Region: Defines specific requirements (e.g., signal A
reaches three times) and the subsequent action once the requirement is
met.
3.Timer/Counter (Optional): Provides timing or counting functionality.

Add a new tgu.yaml file to describe the bindings required to
define the TGU in the device trees.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Songwei Chai <songwei.chai@oss.qualcomm.com>
---
 .../devicetree/bindings/arm/qcom,tgu.yaml     | 71 +++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/qcom,tgu.yaml

diff --git a/Documentation/devicetree/bindings/arm/qcom,tgu.yaml b/Documentation/devicetree/bindings/arm/qcom,tgu.yaml
new file mode 100644
index 000000000000..76440f2497b9
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/qcom,tgu.yaml
@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+# Copyright (c) 2025 Qualcomm Innovation Center, Inc. All rights reserved.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/qcom,tgu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Trigger Generation Unit - TGU
+
+description: |
+  The Trigger Generation Unit (TGU) is a Data Engine which can be utilized
+  to sense a plurality of signals and create a trigger into the CTI or
+  generate interrupts to processors. The TGU is like the trigger circuit
+  of a Logic Analyzer. The corresponding trigger logic can be realized by
+  configuring the conditions for each step after sensing the signal.
+  Once setup and enabled, it will observe sense inputs and based upon
+  the activity of those inputs, even over clock cycles, may detect a
+  preprogrammed state/sequence and then produce a trigger or interrupt.
+
+  The primary use case of the TGU is to detect patterns or sequences on a
+  given set of signals within some region to identify the issue in time
+  once there is abnormal behavior in the subsystem.
+
+maintainers:
+  - Mao Jinlong <jinlong.mao@oss.qualcomm.com>
+  - Songwei Chai <songwei.chai@oss.qualcomm.com>
+
+# Need a custom select here or 'arm,primecell' will match on lots of nodes
+select:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - qcom,tgu
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - const: qcom,tgu
+      - const: arm,primecell
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: apb_pclk
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+
+additionalProperties: false
+
+examples:
+  - |
+    tgu@10b0e000 {
+        compatible = "qcom,tgu", "arm,primecell";
+        reg = <0x10b0e000 0x1000>;
+
+        clocks = <&aoss_qmp>;
+        clock-names = "apb_pclk";
+    };
+...
-- 
2.34.1