[PATCH RFC v5 1/6] dt-bindings: iio: add Open Sensor Fusion device

[Jinseob Kim <kimjinseob88@gmail.com>]

Add the generic Open Sensor Fusion device binding for a serdev-attached
IIO sensor aggregation hub, and document the opensensorfusion vendor
prefix.

The opensensorfusion,osf compatible describes the generic Open Sensor
Fusion host interface. OSF GREEN is not the Linux compatible identity.
Likewise, OSF0 is the current wire magic and a wire-format detail, not
the Linux driver identity.

The fixed OSF frame header carries protocol_major and protocol_minor at
fixed offsets. This driver currently supports protocol_major 0.
protocol_minor changes are intended to remain backward-compatible within
that fixed header layout. Incompatible wire-format changes require a new
protocol_major. If a future device cannot expose compatible version
discovery through the fixed header layout, it will need a different
compatible.

Require vcc-supply so the driver can enable device power before starting
communication.

Signed-off-by: Jinseob Kim <kimjinseob88@gmail.com>
---
 .../bindings/iio/opensensorfusion,osf.yaml    | 59 +++++++++++++++++++
 .../devicetree/bindings/vendor-prefixes.yaml  |  2 +
 MAINTAINERS                                   | 13 ++++
 3 files changed, 74 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/opensensorfusion,osf.yaml

diff --git a/Documentation/devicetree/bindings/iio/opensensorfusion,osf.yaml b/Documentation/devicetree/bindings/iio/opensensorfusion,osf.yaml
new file mode 100644
index 000000000..012a07fd6
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/opensensorfusion,osf.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/opensensorfusion,osf.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Open Sensor Fusion Sensor Aggregation Hub
+
+maintainers:
+  - Jinseob Kim <kimjinseob88@gmail.com>
+
+description: |
+  Open Sensor Fusion is a sensor aggregation hub. The hub exposes an OSF
+  protocol data stream over its host interface and may report capabilities and
+  samples for multiple sensor classes. The Linux driver discovers the actual
+  sensor channels from OSF capability reports instead of describing those
+  sensors in Device Tree.
+
+  Open Sensor Fusion is not a generic industry standard. Public project
+  documentation is available at:
+
+    https://github.com/opensensorfusion
+
+  The compatible describes the generic Open Sensor Fusion host interface. It
+  is not an OSF GREEN board identity, and it does not encode the OSF0 wire
+  magic. OSF0, protocol_major, and protocol_minor are wire-protocol details
+  exchanged in OSF frames.
+
+allOf:
+  - $ref: /schemas/serial/serial-peripheral-props.yaml#
+
+properties:
+  compatible:
+    const: opensensorfusion,osf
+
+  vcc-supply:
+    description:
+      Regulator supplying power to the Open Sensor Fusion device.
+
+required:
+  - compatible
+  - vcc-supply
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    vcc_sensor: regulator-0 {
+        compatible = "regulator-fixed";
+        regulator-name = "sensor-vcc";
+    };
+
+    serial {
+        sensor {
+            compatible = "opensensorfusion,osf";
+            vcc-supply = <&vcc_sensor>;
+        };
+    };
+...
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index 28784d66a..88172d4a4 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -1237,6 +1237,8 @@ patternProperties:
     description: OpenPandora GmbH
   "^openrisc,.*":
     description: OpenRISC.io
+  "^opensensorfusion,.*":
+    description: Open Sensor Fusion
   "^openwrt,.*":
     description: OpenWrt
   "^option,.*":
diff --git a/MAINTAINERS b/MAINTAINERS
index c2c6d7927..2ddefc42d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20011,6 +20011,19 @@ F:	Documentation/devicetree/
 F:	arch/*/boot/dts/
 F:	include/dt-bindings/
 
+OPEN SENSOR FUSION IIO DRIVER
+M:	Jinseob Kim <kimjinseob88@gmail.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/opensensorfusion,osf.yaml
+F:	Documentation/iio/open-sensor-fusion.rst
+F:	drivers/iio/opensensorfusion/Kconfig
+F:	drivers/iio/opensensorfusion/Makefile
+F:	drivers/iio/opensensorfusion/osf_core.*
+F:	drivers/iio/opensensorfusion/osf_iio.*
+F:	drivers/iio/opensensorfusion/osf_protocol.*
+F:	drivers/iio/opensensorfusion/osf_serdev.c
+F:	drivers/iio/opensensorfusion/osf_stream.*
+
 OPENCOMPUTE PTP CLOCK DRIVER
 M:	Vadim Fedorenko <vadim.fedorenko@linux.dev>
 L:	netdev@vger.kernel.org
-- 
2.43.0