[PATCH v2 0/2] drm: bridge: Add TI tmds181 and sn65dp159 driver (RFC)

[PATCH v2 0/2] drm: bridge: Add TI tmds181 and sn65dp159 driver (RFC)

[Mike Looijmans]

In the past I've seen (and contributed to) hacks that model the chips as
phy or even (really!) clock drivers. Since the chip usually sits between
a signal that is (almost) HDMI and a HDMI connector, I decided to stop
lying and write it as a DRM bridge driver.

Our experience with these chips is that they work best under manual control
enabling them only once the signal is active. At low resolutions (under 4k),
the optimal setting is usually to only use redriver mode. Setting the
termination to 150-300 Ohms improves EMC performance at lower resolutions,
hence the driver enables 75-150 Ohms for HDMI2 modes and defaults to
150-300 Ohm termination for other modes.


Changes in v2:
Document driver specific bindings like slew-rate and threshold
Use atomic_enable/disable
Use #defines for bit fields in registers
Allow HDMI 2 compliance
Filter modes on clock range
Use cross-over pixel frequency instead of manual overides
Devicetree bindings according to standards

Mike Looijmans (2):
  dt-bindings: drm/bridge: ti-tmds181: Add TI TMDS181 and SN65DP159
    bindings
  drm: bridge: Add TI tmds181 and sn65dp159 driver

 .../bindings/display/bridge/ti,tmds181.yaml   | 143 +++++
 drivers/gpu/drm/bridge/Kconfig                |  11 +
 drivers/gpu/drm/bridge/Makefile               |   1 +
 drivers/gpu/drm/bridge/ti-tmds181.c           | 561 ++++++++++++++++++
 4 files changed, 716 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml
 create mode 100644 drivers/gpu/drm/bridge/ti-tmds181.c

-- 
2.43.0

base-commit: 53e760d8949895390e256e723e7ee46618310361
branch: drm-ti-tmds181

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

Please consider the environment before printing this e-mail

[PATCH v2 1/2] dt-bindings: drm/bridge: ti-tmds181: Add TI TMDS181 and SN65DP159 bindings

[Mike Looijmans]

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

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

---

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

 .../bindings/display/bridge/ti,tmds181.yaml   | 143 ++++++++++++++++++
 1 file changed, 143 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..816bea54846f
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml
@@ -0,0 +1,143 @@
+# 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/TMDS181
+
+properties:
+  compatible:
+    enum:
+      - ti,tmds181
+      - ti,sn65dp159
+
+  reg:
+    enum:
+      - 0x5b
+      - 0x5c
+      - 0x5d
+      - 0x5e
+
+  oe-gpios:
+    maxItems: 1
+    description: GPIO specifier for OE pin (active high).
+
+  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,source-mode:
+    type: boolean
+    description:
+      Force chip to operate in "source" mode. Allows to use
+      a TMDS181 chip (which defaults to sink) as cable driver.
+
+  ti,sink-mode:
+    type: boolean
+    description:
+      Force chip to operate in "sink" mode. Allows to use
+      a DP159 chip (defaults to source) for incoming signals.
+
+  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.
+
+  ti,dvi-mode:
+    type: boolean
+    description: Makes the DP159 chip operate in DVI mode.
+
+  ti,slew-rate:
+    minimum: 0
+    maximum: 3
+    default: 3
+    description: Set slew rate, 0 is slowest, 3 is fastest.
+
+  ti,disable-equalizer:
+    type: boolean
+    description: Disable the equalizer (to save power).
+
+  ti,adaptive-equalizer:
+    type: boolean
+    description: Set the equalizer to adaptive mode.
+
+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";
+            reg = <0x5b>;
+
+            oe-gpios = <&gpio2 1 GPIO_ACTIVE_HIGH>;
+
+            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

Please consider the environment before printing this e-mail

Re: [PATCH v2 1/2] dt-bindings: drm/bridge: ti-tmds181: Add TI TMDS181 and SN65DP159 bindings

[Rob Herring (Arm)]

On Tue, 19 Aug 2025 07:31:14 +0200, Mike Looijmans wrote:
> Add DT binding document for TI TMDS181 and SN65DP159 HDMI retimers.
> 
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
> 
> ---
> 
> Changes in v2:
> Document driver specific bindings like slew-rate and threshold
> 
>  .../bindings/display/bridge/ti,tmds181.yaml   | 143 ++++++++++++++++++
>  1 file changed, 143 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml: ti,slew-rate: missing type definition

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20250819053205.9976-2-mike.looijmans@topic.nl

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH v2 1/2] dt-bindings: drm/bridge: ti-tmds181: Add TI TMDS181 and SN65DP159 bindings

[Krzysztof Kozlowski]

On Tue, Aug 19, 2025 at 07:31:14AM +0200, Mike Looijmans wrote:
> Add DT binding document for TI TMDS181 and SN65DP159 HDMI retimers.
> 
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
> 
> ---
> 
> Changes in v2:
> Document driver specific bindings like slew-rate and threshold
> 
>  .../bindings/display/bridge/ti,tmds181.yaml   | 143 ++++++++++++++++++
>  1 file changed, 143 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..816bea54846f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml
> @@ -0,0 +1,143 @@
> +# 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/TMDS181
> +
> +properties:
> +  compatible:
> +    enum:
> +      - ti,tmds181
> +      - ti,sn65dp159

Nothing improved, you did not respond to review, you did not say why it
is not implemented in changelog. You did not explain that choice in
commit msg, either.

Best regards,
Krzysztof

Re: [PATCH v2 1/2] dt-bindings: drm/bridge: ti-tmds181: Add TI TMDS181 and SN65DP159 bindings

[Mike Looijmans]

On 19-08-2025 09:03, Krzysztof Kozlowski wrote:
> On Tue, Aug 19, 2025 at 07:31:14AM +0200, Mike Looijmans wrote:
>> Add DT binding document for TI TMDS181 and SN65DP159 HDMI retimers.
>>
>> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
>>
>> ---
>>
>> Changes in v2:
>> Document driver specific bindings like slew-rate and threshold
>>
>>   .../bindings/display/bridge/ti,tmds181.yaml   | 143 ++++++++++++++++++
>>   1 file changed, 143 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..816bea54846f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/display/bridge/ti,tmds181.yaml
>> @@ -0,0 +1,143 @@
>> +# 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/TMDS181
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - ti,tmds181
>> +      - ti,sn65dp159
> Nothing improved, you did not respond to review, you did not say why it
> is not implemented in changelog. You did not explain that choice in
> commit msg, either.

Apologies, my bad. I totally forgot.


>
> Best regards,
> Krzysztof

-- 
Mike Looijmans