Add DT binding document for TI TMDS181 and SN65DP159 HDMI retimers.

The two chips have similar register maps, but different applications
(source vs. sink).

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>

---

Changes in v6:
Rename ti,mode to ti,retimer-mode

Changes in v5:
ti,equalizer and ti,mode changed to enum
Rename ti,slew-rate to slew-rate
Make properties conditional for DP159/TMDS181
Remove ti,dvi-mode (always set to avoid conflict)

Changes in v4:
Use fallback compatible

Changes in v3:
Fix duplicate links
Add vcc-supply and vdd-supply
Fix missing type for ti,slew-rate

Changes in v2:
Document driver specific bindings like slew-rate and threshold

 .../bindings/display/bridge/ti,tmds181.yaml   | 170 ++++++++++++++++++
 1 file changed, 170 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml

diff --git a/Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml b/Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml
new file mode 100644
index 000000000000..9b23221634bb
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml
@@ -0,0 +1,170 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/ti,tmds181.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TMDS181 and SN65DP159 HDMI retimer/redriver chips
+
+maintainers:
+  - Mike Looijmans <mike.looijmans@topic.nl>
+
+description: |
+  Texas Instruments TMDS181 and SN65DP159 retimer and redriver chips.
+  https://www.ti.com/product/TMDS181
+  https://www.ti.com/product/SN65DP159
+  When I2C control is enabled, various pin strapping options like equalizer and
+  slew-rate are unavailable. These can be configured through I2C using the
+  properties defined here.
+  A common application for these chips is to convert AC coupled serdes outputs
+  from an FPGA or SoC into HDMI compliant signals.
+
+properties:
+  compatible:
+    oneOf:
+      - const: ti,tmds181
+      - items:
+          - const: ti,sn65dp159
+          - const: ti,tmds181
+
+  reg:
+    enum:
+      - 0x5b
+      - 0x5c
+      - 0x5d
+      - 0x5e
+
+  reset-gpios:
+    maxItems: 1
+    description: GPIO specifier for OE pin which acts as active low reset.
+
+  vdd-supply:
+    description: Core power supply, 1.1V
+
+  vcc-supply:
+    description: IO power supply, 3.3V
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        unevaluatedProperties: false
+        description: Video port for HDMI (ish) input
+
+        properties:
+          endpoint:
+            $ref: /schemas/media/video-interfaces.yaml#
+            unevaluatedProperties: false
+
+      port@1:
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        unevaluatedProperties: false
+        description: Video port for HDMI output (panel or bridge)
+
+        properties:
+          endpoint:
+            $ref: /schemas/media/video-interfaces.yaml#
+            unevaluatedProperties: false
+
+    required:
+      - port@0
+      - port@1
+
+  ti,retimer-mode:
+    enum:
+      - source
+      - sink
+    description:
+      Force chip to operate in "source" or "sink" mode.
+
+  ti,retimer-threshold-hz:
+    minimum: 25000000
+    maximum: 600000000
+    default: 200000000
+    description:
+      Cross-over point. Up until this pixel clock frequency the chip remains in
+      the low-power redriver mode. Above the threshold the chip should operate
+      in retimer mode.
+
+  slew-rate:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 0
+    maximum: 3
+    default: 3
+    description: Set slew rate, 0 is slowest, 3 is fastest.
+
+  ti,equalizer:
+    enum:
+      - adaptive
+      - disabled
+      - fixed
+    default: adaptive
+    description: Configure the equalizer
+
+if:
+  properties:
+    compatible:
+      contains:
+        const: ti,sn65dp159
+
+then:
+  properties:
+    ti,retimer-mode:
+      default: source
+
+else:
+  properties:
+    ti,retimer-mode:
+      default: sink
+    slew-rate: false
+
+required:
+  - compatible
+  - reg
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        bridge@5b {
+            compatible = "ti,sn65dp159", "ti,tmds181";
+            reg = <0x5b>;
+            vdd-supply = <&vcc_1v1_reg>;
+            vcc-supply = <&vcc_3v3_reg>;
+            reset-gpios = <&gpio2 1 GPIO_ACTIVE_LOW>;
+            slew-rate = <2>;
+            ti,retimer-threshold-hz = <350000000>;
+            ti,retimer-mode = "source";
+            ti,equalizer = "disabled";
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                port@0 {
+                    reg = <0>;
+
+                    endpoint {
+                        remote-endpoint = <&encoder_out>;
+                    };
+                };
+
+                port@1 {
+                    reg = <1>;
+
+                    endpoint {
+                        remote-endpoint = <&hdmi_connector_in>;
+                    };
+                };
+            };
+        };
+    };
-- 
2.43.0


Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: +31 (0) 499 33 69 69
E: mike.looijmans@topic.nl
W: www.topic.nl

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