[PATCH 1/2] dt-bindings: phy: qcom: Add SA8797P eUSB2 PHY

[Hiren Gohel]

SA8797p platform abstracts resources such as resets, clocks and
regulators in firmware. The SCMI firmware exposes multiple protocols to
control such resources which are identified by protocol_id.

For this USB phy, 2 SCMI protocols are exposed by the firmware:
* power domain management protocol (protocol_id=0x11)
* performance domain management protocol (protocol_id=0x13)

The power domain has 2 indices: 'core' and 'transfer'.
* core controls the regulators, the clocks and the reset
* transfer only controls the clocks

For example, to power on/off the PHY, we should use the 'core' domain.
To disable data transfer and keeping power enabled, we should use the
'transfer' domain.

Add a new binding for the Synopsys eusb2 High-Speed USB PHY
found in SA8797P.

Note: the performance domain (0x13) exposes opaques values (0xa to 0x11)
for which we don't have any information. Since it is not mandatory
for the PHY to be functional, we have ommited it from the bindings.
We can document it (and make them part of the dt ABI) once we have more
information.

Signed-off-by: Hiren Gohel <hiren.gohel at oss.qualcomm.com>
---
 .../phy/qcom,sa8797p-snps-eusb2-phy.yaml      | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/qcom,sa8797p-snps-eusb2-phy.yaml

diff --git a/Documentation/devicetree/bindings/phy/qcom,sa8797p-snps-eusb2-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sa8797p-snps-eusb2-phy.yaml
new file mode 100644
index 000000000000..0a9f44199490
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/qcom,sa8797p-snps-eusb2-phy.yaml
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/qcom,sa8797p-snps-eusb2-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm SA8797P Synopsys eUSB2 PHY
+
+maintainers:
+  - Hiren Gohel <hiren.gohel at oss.qualcomm.com>
+
+description:
+  The Qualcomm SA8797P platform delegates control of the eUSB2 PHY clocks,
+  reset, and other platform resources to firmware. The SCMI power protocol
+  exposes two power domains for the PHY. The core domain controls the PHY
+  power, reset, and clocks, while the transfer domain controls the clocks used
+  for data transfer. The SCMI performance domain is not required for PHY
+  operation and its opaque performance values are not part of this binding.
+
+properties:
+  compatible:
+    const: qcom,sa8797p-snps-eusb2-phy
+
+  reg:
+    maxItems: 1
+
+  "#phy-cells":
+    const: 0
+
+  power-domains:
+    items:
+      - description: Core domain controlling PHY power, reset, and clocks
+      - description: Transfer domain controlling the data-transfer clocks
+
+  power-domain-names:
+    items:
+      - const: core
+      - const: transfer
+
+  phys:
+    maxItems: 1
+    description:
+      Phandle to the eUSB2 to USB 2.0 repeater.
+
+required:
+  - compatible
+  - reg
+  - "#phy-cells"
+  - power-domains
+  - power-domain-names
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        phy at 88e3000 {
+            compatible = "qcom,sa8797p-snps-eusb2-phy";
+            reg = <0x0 0x088e3000 0x0 0x154>;
+            #phy-cells = <0>;
+
+            power-domains = <&scmi12_pd 1>, <&scmi12_pd 0>;
+            power-domain-names = "core", "transfer";
+        };
+    };
-- 
2.34.1