[PATCH v27 2/4] dt-bindings: i2c: ast2600-i2c.yaml: Add global-regs and transfer-mode properties

[Ryan Chen <ryan_chen@aspeedtech.com>]

The AST2600 I2C controller supports three transfer modes (byte, buffer,
DMA). Add "aspeed,transfer-mode" so DT can select the preferred transfer
method per controller instance. Also add the "aspeed,global-regs"
phandle to reference the AST2600 global registers syscon/regmap used by
the controller.

These properties apply only to the AST2600 binding and are not part of
the legacy binding, which uses a mixed controller/target register layout
and does not have the split register blocks or these new configuration
registers. Legacy DTs remain unchanged.

Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
---
Changes in v27:
- change aspeed,transfer-mode to aspeed,enable-dma.
---
 .../devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml     | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml b/Documentation/devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml
index de2c359037da..38da6fc6424f 100644
--- a/Documentation/devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml
+++ b/Documentation/devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml
@@ -37,6 +37,21 @@ properties:
   resets:
     maxItems: 1
 
+  aspeed,enable-dma:
+    type: boolean
+    description: |
+      I2C bus enable dma mode transfer.
+
+      ASPEED ast2600 platform equipped with 16 I2C controllers that share a
+      single DMA engine. DTS files can specify the data transfer mode to/from
+      the device, either DMA or programmed I/O.
+
+  aspeed,global-regs:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle reference to the i2c global syscon node, containing the
+      SoC-common i2c register set.
+
 required:
   - reg
   - compatible
@@ -59,4 +74,6 @@ examples:
         resets = <&syscon ASPEED_RESET_I2C>;
         clock-frequency = <100000>;
         interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_HIGH>;
+        aspeed,global-regs = <&i2c_global>;
+        aspeed,transfer-mode = "buffer";
     };

-- 
2.34.1