[PATCH v4 1/2] dt-bindings: i2c: Add Synopsys DWC_i2c controller

[Aniket Limaye <a-limaye@ti.com>]

Add documentation for the Synopsys Advanced I2C (DWC_i2c) controller, as
found on the TI TDA54 SoC.

The block cannot work on its own and needs SoC integration, e.g. the
FIFO depths are not discoverable from the IP. Do not add a generic
compatible and only list SoC specific compatibles. The file is named
after the IP so that other SoCs integrating it can be added here.

Signed-off-by: Aniket Limaye <a-limaye@ti.com>

---

Changes in v4:
- Drop the approach of extending the existing i2c-designware-* driver
  with a MODEL_TI_TDA54 variant. Instead, add a new standalone driver
  (i2c-dwc-adv.c) and a new binding (snps,dwc-adv-i2c.yaml), since
  DWC_i2c is not register compatible with DW_apb_i2c. (Andy Shevchenko)
- Drop the snps,tx-fifo-depth/snps,rx-fifo-depth DT properties from
  the new binding; FIFO depth is now tied to the compatible string via
  driver match data instead. (Conor Dooley)
- Link to v3: https://lore.kernel.org/all/20260925-tda54-upstream-i2c-v3-1-544d74e992ff@ti.com/

Changes in v2:
- Rename snps,dwc-i2c to ti,tda54-i2c
- Link to v1: https://lore.kernel.org/r/20260919-tda54-upstream-i2c-v1-1-b0b9f77be18b@ti.com/
---
 .../devicetree/bindings/i2c/snps,dwc-adv-i2c.yaml  | 75 ++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/snps,dwc-adv-i2c.yaml b/Documentation/devicetree/bindings/i2c/snps,dwc-adv-i2c.yaml
new file mode 100644
index 000000000000..7ad22536825e
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/snps,dwc-adv-i2c.yaml
@@ -0,0 +1,75 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/snps,dwc-adv-i2c.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Synopsys DesignWare Advanced I2C (DWC_i2c) Controller
+
+maintainers:
+  - Aniket Limaye <a-limaye@ti.com>
+
+allOf:
+  - $ref: /schemas/i2c/i2c-controller.yaml#
+
+properties:
+  compatible:
+    enum:
+      - ti,tda54-i2c
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: I2C functional clock (ic_clk)
+      - description: Register interface clock (pclk)
+
+  clock-names:
+    items:
+      - const: ref
+      - const: pclk
+
+  resets:
+    maxItems: 1
+
+  clock-frequency:
+    enum: [100000, 400000, 1000000, 3400000]
+    default: 400000
+
+  i2c-sda-hold-time-ns: true
+
+  i2c-scl-falling-time-ns:
+    default: 300
+
+  i2c-sda-falling-time-ns:
+    default: 300
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    i2c@53b00000 {
+        compatible = "ti,tda54-i2c";
+        reg = <0x53b00000 0x1000>;
+        interrupts = <GIC_SPI 166 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&sysclk>, <&pclk>;
+        clock-names = "ref", "pclk";
+        clock-frequency = <400000>;
+        i2c-sda-hold-time-ns = <300>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+    };
+...

-- 
2.53.0