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[1/3] dt-bindings: usb: fsa4480: Add data-lanes property to endpoint

Message ID 20231013-fsa4480-swap-v1-1-b877f62046cc@fairphone.com
State New
Headers show
Series Handle reversed SBU orientation for FSA4480 | expand

Commit Message

Luca Weiss Oct. 13, 2023, 11:38 a.m. UTC
Allow specifying data-lanes to reverse the SBU muxing orientation where
necessary by the hardware design.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 .../devicetree/bindings/usb/fcs,fsa4480.yaml       | 29 +++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

Comments

Rob Herring (Arm) Oct. 16, 2023, 2:22 p.m. UTC | #1
On Fri, Oct 13, 2023 at 01:38:05PM +0200, Luca Weiss wrote:
> Allow specifying data-lanes to reverse the SBU muxing orientation where
> necessary by the hardware design.

What situation in the hardware design makes this necessary. Please 
describe the problem.

> 
> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> ---
>  .../devicetree/bindings/usb/fcs,fsa4480.yaml       | 29 +++++++++++++++++++++-
>  1 file changed, 28 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
> index f6e7a5c1ff0b..86f6d633c2fb 100644
> --- a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
> +++ b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
> @@ -32,10 +32,37 @@ properties:
>      type: boolean
>  
>    port:
> -    $ref: /schemas/graph.yaml#/properties/port
> +    $ref: /schemas/graph.yaml#/$defs/port-base
>      description:
>        A port node to link the FSA4480 to a TypeC controller for the purpose of
>        handling altmode muxing and orientation switching.
> +    unevaluatedProperties: false
> +
> +    properties:
> +      endpoint:
> +        $ref: /schemas/graph.yaml#/$defs/endpoint-base
> +        unevaluatedProperties: false
> +
> +        properties:
> +          data-lanes:
> +            $ref: /schemas/types.yaml#/definitions/uint32-array
> +            description:
> +              Specifies how the AUX+/- lines are connected to SBU1/2.

Doesn't this depend on the connector orientation? Or it is both that and 
the lines can be swapped on the PCB?

Seems like an abuse of data-lanes which already has a definition which 
is not about swapping + and - differential lanes.

Rob
Neil Armstrong Oct. 16, 2023, 2:32 p.m. UTC | #2
On 16/10/2023 16:22, Rob Herring wrote:
> On Fri, Oct 13, 2023 at 01:38:05PM +0200, Luca Weiss wrote:
>> Allow specifying data-lanes to reverse the SBU muxing orientation where
>> necessary by the hardware design.
> 
> What situation in the hardware design makes this necessary. Please
> describe the problem.
> 
>>
>> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
>> ---
>>   .../devicetree/bindings/usb/fcs,fsa4480.yaml       | 29 +++++++++++++++++++++-
>>   1 file changed, 28 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
>> index f6e7a5c1ff0b..86f6d633c2fb 100644
>> --- a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
>> +++ b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
>> @@ -32,10 +32,37 @@ properties:
>>       type: boolean
>>   
>>     port:
>> -    $ref: /schemas/graph.yaml#/properties/port
>> +    $ref: /schemas/graph.yaml#/$defs/port-base
>>       description:
>>         A port node to link the FSA4480 to a TypeC controller for the purpose of
>>         handling altmode muxing and orientation switching.
>> +    unevaluatedProperties: false
>> +
>> +    properties:
>> +      endpoint:
>> +        $ref: /schemas/graph.yaml#/$defs/endpoint-base
>> +        unevaluatedProperties: false
>> +
>> +        properties:
>> +          data-lanes:
>> +            $ref: /schemas/types.yaml#/definitions/uint32-array
>> +            description:
>> +              Specifies how the AUX+/- lines are connected to SBU1/2.
> 
> Doesn't this depend on the connector orientation? Or it is both that and
> the lines can be swapped on the PCB?
> 
> Seems like an abuse of data-lanes which already has a definition which
> is not about swapping + and - differential lanes.

The FSA acts as a mux between DP AUX, Audio lanes on one side and
the USB-C SBU lanes on the other side.
_______          ______
       |          |     |
       |-- HP   --|     |
       |-- MIC  --|     |or
SoC   |          | MUX |-- SBU1 --->  To the USB-C
Codec |-- AUX+ --|     |-- SBU2 --->  connected
       |-- AUX- --|     |
______|          |____ |

The SBU1 & SBU2 are connected to the USB-C connector, and the actual orientation
to the connected devices/cable/whatever is determined by the TPCM and the MUX in
the FSA4480 with be dynamically changed according to the CC1/CC2 detection and PD alt mode.

But on the other side the orientation of the AUX+/AUX- connected to the SoC
is not tied to the USB-C orientation but how it's routed on the PCB.

This describes how the AUX+/AUX- are physically routed to the FSA4480 chip.

Neil

> 
> Rob
Rob Herring (Arm) Oct. 17, 2023, 7:12 p.m. UTC | #3
On Mon, Oct 16, 2023 at 04:32:55PM +0200, Neil Armstrong wrote:
> On 16/10/2023 16:22, Rob Herring wrote:
> > On Fri, Oct 13, 2023 at 01:38:05PM +0200, Luca Weiss wrote:
> > > Allow specifying data-lanes to reverse the SBU muxing orientation where
> > > necessary by the hardware design.
> > 
> > What situation in the hardware design makes this necessary. Please
> > describe the problem.
> > 
> > > 
> > > Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> > > ---
> > >   .../devicetree/bindings/usb/fcs,fsa4480.yaml       | 29 +++++++++++++++++++++-
> > >   1 file changed, 28 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
> > > index f6e7a5c1ff0b..86f6d633c2fb 100644
> > > --- a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
> > > +++ b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
> > > @@ -32,10 +32,37 @@ properties:
> > >       type: boolean
> > >     port:
> > > -    $ref: /schemas/graph.yaml#/properties/port
> > > +    $ref: /schemas/graph.yaml#/$defs/port-base
> > >       description:
> > >         A port node to link the FSA4480 to a TypeC controller for the purpose of
> > >         handling altmode muxing and orientation switching.
> > > +    unevaluatedProperties: false
> > > +
> > > +    properties:
> > > +      endpoint:
> > > +        $ref: /schemas/graph.yaml#/$defs/endpoint-base
> > > +        unevaluatedProperties: false
> > > +
> > > +        properties:
> > > +          data-lanes:
> > > +            $ref: /schemas/types.yaml#/definitions/uint32-array
> > > +            description:
> > > +              Specifies how the AUX+/- lines are connected to SBU1/2.
> > 
> > Doesn't this depend on the connector orientation? Or it is both that and
> > the lines can be swapped on the PCB?
> > 
> > Seems like an abuse of data-lanes which already has a definition which
> > is not about swapping + and - differential lanes.
> 
> The FSA acts as a mux between DP AUX, Audio lanes on one side and
> the USB-C SBU lanes on the other side.
> _______          ______
>       |          |     |
>       |-- HP   --|     |
>       |-- MIC  --|     |or
> SoC   |          | MUX |-- SBU1 --->  To the USB-C
> Codec |-- AUX+ --|     |-- SBU2 --->  connected
>       |-- AUX- --|     |
> ______|          |____ |
> 
> The SBU1 & SBU2 are connected to the USB-C connector, and the actual orientation
> to the connected devices/cable/whatever is determined by the TPCM and the MUX in
> the FSA4480 with be dynamically changed according to the CC1/CC2 detection and PD alt mode.
> 
> But on the other side the orientation of the AUX+/AUX- connected to the SoC
> is not tied to the USB-C orientation but how it's routed on the PCB.
> 
> This describes how the AUX+/AUX- are physically routed to the FSA4480 chip.

I'd hate for this ASCII art to go to waste. Please add this detail to 
the commit message.

Rob
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
index f6e7a5c1ff0b..86f6d633c2fb 100644
--- a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
+++ b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
@@ -32,10 +32,37 @@  properties:
     type: boolean
 
   port:
-    $ref: /schemas/graph.yaml#/properties/port
+    $ref: /schemas/graph.yaml#/$defs/port-base
     description:
       A port node to link the FSA4480 to a TypeC controller for the purpose of
       handling altmode muxing and orientation switching.
+    unevaluatedProperties: false
+
+    properties:
+      endpoint:
+        $ref: /schemas/graph.yaml#/$defs/endpoint-base
+        unevaluatedProperties: false
+
+        properties:
+          data-lanes:
+            $ref: /schemas/types.yaml#/definitions/uint32-array
+            description:
+              Specifies how the AUX+/- lines are connected to SBU1/2.
+            oneOf:
+              - items:
+                  - const: 0
+                  - const: 1
+                description: |
+                  Default AUX/SBU layout
+                  - AUX+ connected to SBU2
+                  - AUX- connected to SBU1
+              - items:
+                  - const: 1
+                  - const: 0
+                description: |
+                  Swapped AUX/SBU layout
+                  - AUX+ connected to SBU1
+                  - AUX- connected to SBU2
 
 required:
   - compatible