Add a base schema initially compatible with x1e80100 to describe MIPI CSI2
PHY devices.

The hardware can support both C-PHY and D-PHY modes. The CSIPHY devices
have their own pinouts on the SoC as well as their own individual voltage
rails.

The need to model voltage rails on a per-PHY basis leads us to define
CSIPHY devices as individual nodes.

Two nice outcomes in terms of schema and DT arise from this change.

1. The ability to define on a per-PHY basis voltage rails.
2. The ability to require those voltage.

We have had a complete bodge upstream for this where a single set of
voltage rail for all CSIPHYs has been buried inside of CAMSS.

Much like the I2C bus which is dedicated to Camera sensors - the CCI bus in
CAMSS parlance, the CSIPHY devices should be individually modelled.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
  .../phy/qcom,x1e80100-mipi-csi2-combo-phy.yaml     | 95 ++++++++++++++++++++++
  1 file changed, 95 insertions(+)

diff --git a/Documentation/devicetree/bindings/phy/qcom,x1e80100-mipi-csi2-combo-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,x1e80100-mipi-csi2-combo-phy.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..e0976f012516452ae3632ff4732620b5c5402d3b
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/qcom,x1e80100-mipi-csi2-combo-phy.yaml

@@ -0,0 +1,95 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/qcom,x1e80100-mipi-csi2-combo-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm MIPI CSI2 Combo PHY
+
+maintainers:
+  - Bryan O'Donoghue <bod@kernel.org>
+
+description:
+  Qualcomm MIPI CSI2 C-PHY/D-PHY combination PHY. Connects MIPI CSI2 sensors
+  to Qualcomm's Camera CSI Decoder. The PHY supports both C-PHY and D-PHY
+  modes.
+
+properties:
+  compatible:
+    const: qcom,x1e80100-mipi-csi2-combo-phy
+
+  reg:
+    maxItems: 1
+
+  "#phy-cells":
+    const: 0
+
+  clocks:
+    maxItems: 4
+
+  clock-names:
+    items:
+      - const: camnoc_axi
+      - const: cpas_ahb
+      - const: csiphy
+      - const: csiphy_timer
+
+  interrupts:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  vdda-0p8-supply:
+    description: Phandle to a 0.8V regulator supply to a PHY.
+
+  vdda-1p2-supply:
+    description: Phandle to 1.2V regulator supply to a PHY.
+
+  phy-type:
+    description: D-PHY or C-PHY mode
+    enum: [ 10, 11 ]
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+required:
+  - compatible
+  - reg
+  - "#phy-cells"
+  - clocks
+  - clock-names
+  - vdda-0p8-supply
+  - vdda-1p2-supply
+  - phy-type
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/qcom,x1e80100-camcc.h>
+    #include <dt-bindings/clock/qcom,x1e80100-gcc.h>
+    #include <dt-bindings/phy/phy.h>
+
+    csiphy0: csiphy@ace4000 {
+        compatible = "qcom,x1e80100-mipi-csi2-combo-phy";
+        reg = <0x0ace4000 0x2000>;
+        #phy-cells = <0>;
+
+        clocks = <&camcc CAM_CC_CAMNOC_AXI_RT_CLK>,
+                 <&camcc CAM_CC_CPAS_AHB_CLK>,
+                 <&camcc CAM_CC_CSIPHY0_CLK>,
+                 <&camcc CAM_CC_CSI0PHYTIMER_CLK>;
+        clock-names = "camnoc_axi",
+                      "cpas_ahb",
+                      "csiphy",
+                      "csiphy_timer";
+
+        interrupts = <GIC_SPI 477 IRQ_TYPE_EDGE_RISING>;
+
+        power-domains = <&camcc CAM_CC_TITAN_TOP_GDSC>;
+
+        vdda-0p8-supply = <&vreg_l2c_0p8>;
+        vdda-1p2-supply = <&vreg_l1c_1p2>;
+
+        phy-type = <PHY_TYPE_DPHY>;
+    };