diff --git a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml
index c79c8a167c46..99ed9b416e94 100644
--- a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml
+++ b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml
@@ -22,6 +22,21 @@ allOf:
       properties:
         reg:
           minItems: 2
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - baikal,bt1-sys-ssi
+    then:
+      properties:
+        mux-controls:
+          maxItems: 1
+      required:
+        - mux-controls
+    else:
+      required:
+        - interrupts
 
 properties:
   compatible:
@@ -46,12 +61,16 @@ properties:
           - const: snps,dw-apb-ssi
       - description: Intel Keem Bay SPI Controller
         const: intel,keembay-ssi
+      - description: Baikal-T1 SPI Controller
+        const: baikal,bt1-ssi
+      - description: Baikal-T1 System Boot SPI Controller
+        const: baikal,bt1-sys-ssi
 
   reg:
     minItems: 1
     items:
       - description: DW APB SSI controller memory mapped registers
-      - description: SPI MST region map
+      - description: SPI MST region map or directly mapped SPI ROM
 
   interrupts:
     maxItems: 1
@@ -129,7 +148,6 @@ required:
   - reg
   - "#address-cells"
   - "#size-cells"
-  - interrupts
   - clocks
 
 examples:
@@ -151,4 +169,15 @@ examples:
         rx-sample-delay-ns = <7>;
       };
     };
+  - |
+    spi@1f040100 {
+      compatible = "baikal,bt1-sys-ssi";
+      reg = <0x1f040100 0x900>,
+            <0x1c000000 0x1000000>;
+      #address-cells = <1>;
+      #size-cells = <0>;
+      mux-controls = <&boot_mux>;
+      clocks = <&ccu_sys>;
+      clock-names = "ssi_clk";
+    };
 ...