scsi: ufs: dt-bindings: Document bindings for SA8255P UFS Host Controller

Document the device tree bindings for UFS host controller on Qualcomm
SA8255P platform which integrates firmware-managed resources.

The platform firmware implements the SCMI server and manages resources
such as the PHY, clocks, regulators and resets via the SCMI power
protocol. As a result, the OS-visible DT only describes the controller’s
MMIO, interrupt, IOMMU and power-domain interfaces.

The generic "qcom,ufshc" and "jedec,ufs-2.0" compatible strings are
removed from the binding, since this firmware managed design won't be
compatible with the drivers doing full resource management.

Co-developed-by: Anjana Hari <anjana.hari@oss.qualcomm.com>
Signed-off-by: Anjana Hari <anjana.hari@oss.qualcomm.com>
Signed-off-by: Ram Kumar Dwivedi <ram.dwivedi@oss.qualcomm.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Acked-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20260113080046.284089-3-ram.dwivedi@oss.qualcomm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/Documentation/devicetree/bindings/ufs/qcom,sa8255p-ufshc.yaml b/Documentation/devicetree/bindings/ufs/qcom,sa8255p-ufshc.yaml
new file mode 100644 (file)
index 0000000..75fae9f
--- /dev/null
+++ b/Documentation/devicetree/bindings/ufs/qcom,sa8255p-ufshc.yaml
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ufs/qcom,sa8255p-ufshc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm SA8255P UFS Host Controller
+
+maintainers:
+  - Ram Kumar Dwivedi <ram.dwivedi@oss.qualcomm.com>
+
+properties:
+  compatible:
+    const: qcom,sa8255p-ufshc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  iommus:
+    maxItems: 1
+
+  dma-coherent: true
+
+  power-domains:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - power-domains
+  - iommus
+  - dma-coherent
+
+allOf:
+  - $ref: ufs-common.yaml
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    ufshc@1d84000 {
+        compatible = "qcom,sa8255p-ufshc";
+        reg = <0x01d84000 0x3000>;
+        interrupts = <GIC_SPI 265 IRQ_TYPE_LEVEL_HIGH>;
+        lanes-per-direction = <2>;
+
+        iommus = <&apps_smmu 0x100 0x0>;
+        power-domains = <&scmi3_pd 0>;
+        dma-coherent;
+    };