[PATCH v2 20/23] dt-bindings: ata: ahci: Add Baikal-T1 AHCI SATA controller DT schema

[Serge Semin]

Baikal-T1 AHCI controller is based on the DWC AHCI SATA IP-core v4.10a
with the next specific settings: two SATA ports, cascaded CSR access based
on two clock domains (APB and AXI), selectable source of the reference
clock (though stable work is currently available from the external source
only), two reset lanes for the application and SATA ports domains. Other
than that the device is fully compatible with the generic DWC AHCI SATA
bindings.

Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>

---

Changelog v2:
- Rename 'syscon' property to 'baikal,bt1-syscon'.
- Drop macro usage from the example node.
---
 .../bindings/ata/baikal,bt1-ahci.yaml         | 127 ++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml

diff --git a/Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml b/Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml
new file mode 100644
index 000000000000..7c2eae75434f
--- /dev/null
+++ b/Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml
@@ -0,0 +1,127 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ata/baikal,bt1-ahci.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Baikal-T1 SoC AHCI SATA controller
+
+maintainers:
+  - Serge Semin <fancer.lancer@xxxxxxxxx>
+
+description: |
+  AHCI SATA controller embedded into the Baikal-T1 SoC is based on the
+  DWC AHCI SATA v4.10a IP-core.
+
+allOf:
+  - $ref: snps,dwc-ahci.yaml#
+
+properties:
+  compatible:
+    contains:
+      const: baikal,bt1-ahci
+
+  clocks:
+    items:
+      - description: Peripheral APB bus clock source
+      - description: Application AXI BIU clock
+      - description: Internal SATA Ports reference clock
+      - description: External SATA Ports reference clock
+
+  clock-names:
+    items:
+      - const: pclk
+      - const: aclk
+      - const: ref_int
+      - const: ref_ext
+
+  resets:
+    items:
+      - description: Application AXI BIU domain reset
+      - description: SATA Ports clock domain reset
+
+  reset-names:
+    items:
+      - const: arst
+      - const: ref
+
+  baikal,bt1-syscon:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle reference to the CCU system controller. It is required to
+      switch between internal and external SATA reference clock sources.
+
+  ports-implemented:
+    maximum: 0x3
+
+patternProperties:
+  "^sata-port@[0-9a-e]$":
+    type: object
+
+    properties:
+      reg:
+        minimum: 0
+        maximum: 1
+
+      snps,tx-ts-max:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          Due to having AXI3 bus interface utilized the maximum Tx DMA
+          transaction size can't exceed 16 beats (AxLEN[3:0]).
+        minimum: 1
+        maximum: 16
+
+      snps,rx-ts-max:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          Due to having AXI3 bus interface utilized the maximum Rx DMA
+          transaction size can't exceed 16 beats (AxLEN[3:0]).
+        minimum: 1
+        maximum: 16
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - resets
+  - baikal,bt1-syscon
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    sata@1f050000 {
+      compatible = "baikal,bt1-ahci", "snps,dwc-ahci";
+      reg = <0x1f050000 0x2000>;
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      interrupts = <0 64 4>;
+
+      clocks = <&ccu_sys 1>, <&ccu_axi 2>, <&ccu_sys 0>, <&clk_sata>;
+      clock-names = "pclk", "aclk", "ref_int", "ref_ext";
+
+      resets = <&ccu_axi 2>, <&ccu_sys 0>;
+      reset-names = "arst", "ref";
+
+      baikal,bt1-syscon = <&syscon>;
+
+      ports-implemented = <0x3>;
+
+      sata-port@0 {
+        reg = <0>;
+
+        snps,tx-ts-max = <4>;
+        snps,rx-ts-max = <4>;
+      };
+
+      sata-port@1 {
+        reg = <1>;
+
+        snps,tx-ts-max = <4>;
+        snps,rx-ts-max = <4>;
+      };
+    };
+...
-- 
2.35.1