[PATCH v11 04/14] dt-bindings: Add bindings document of Aspeed PECI adapter

[Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>]

This commit adds bindings document of Aspeed PECI adapter for ASPEED
AST24xx/25xx/26xx SoCs.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Andrew Jeffery <andrew@aj.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason M Biils <jason.m.bills@linux.intel.com>
Cc: Milton Miller II <miltonm@us.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Ryan Chen <ryan_chen@aspeedtech.com>
Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
---
Changes since v10:
- Changed documents format to DT schema format so I dropped all review tags.
  Please review it again.

 .../devicetree/bindings/peci/peci-aspeed.yaml | 124 ++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/peci/peci-aspeed.yaml

diff --git a/Documentation/devicetree/bindings/peci/peci-aspeed.yaml b/Documentation/devicetree/bindings/peci/peci-aspeed.yaml
new file mode 100644
index 000000000000..0f5c2993fe9b
--- /dev/null
+++ b/Documentation/devicetree/bindings/peci/peci-aspeed.yaml
@@ -0,0 +1,124 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/peci/peci-aspeed.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Aspeed PECI Bus Device Tree Bindings
+
+maintainers:
+  - Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
+
+properties:
+  compatible:
+    enum:
+      - aspeed,ast2400-peci
+      - aspeed,ast2500-peci
+      - aspeed,ast2600-peci
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    # Required to define a client address.
+    const: 1
+
+  "#size-cells":
+    # Required to define a client address.
+    const: 0
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: |
+      Clock source for PECI controller. Should reference the external
+      oscillator clock.
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  clock-frequency:
+    # Operation frequency of PECI controller in units of Hz.
+    minimum: 187500
+    maximum: 24000000
+
+  msg-timing:
+    description: |
+      Message timing negotiation period. This value will determine the period
+      of message timing negotiation to be issued by PECI controller. The unit
+      of the programmed value is four times of PECI clock period.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - minimum: 0
+        maximum: 255
+        default: 1
+
+  addr-timing:
+    description: |
+      Address timing negotiation period. This value will determine the period
+      of address timing negotiation to be issued by PECI controller. The unit
+      of the programmed value is four times of PECI clock period.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - minimum: 0
+        maximum: 255
+        default: 1
+
+  rd-sampling-point:
+    description: |
+      Read sampling point selection. The whole period of a bit time will be
+      divided into 16 time frames. This value will determine the time frame
+      in which the controller will sample PECI signal for data read back.
+      Usually in the middle of a bit time is the best.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - minimum: 0
+        maximum: 15
+        default: 8
+
+  cmd-timeout-ms:
+    # Command timeout in units of ms.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - minimum: 1
+        maximum: 60000
+        default: 1000
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+  - interrupts
+  - clocks
+  - resets
+  - clock-frequency
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/ast2600-clock.h>
+    peci: bus@1e78b000 {
+        compatible = "simple-bus";
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0x0 0x1e78b000 0x60>;
+
+        peci0: peci-bus@0 {
+            compatible = "aspeed,ast2600-peci";
+            reg = <0x0 0x100>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+            interrupts = <GIC_SPI 38 IRQ_TYPE_LEVEL_HIGH>;
+            clocks = <&syscon ASPEED_CLK_GATE_REF0CLK>;
+            resets = <&syscon ASPEED_RESET_PECI>;
+            clock-frequency = <24000000>;
+            msg-timing = <1>;
+            addr-timing = <1>;
+            rd-sampling-point = <8>;
+            cmd-timeout-ms = <1000>;
+        };
+    };
+...
-- 
2.17.1