On 22/06/2026 14:08, Laurent Pinchart wrote: > On Mon, Jun 22, 2026 at 05:31:36PM +0530, Mohit Dsor wrote: >> On Thu, Jun 11, 2026 at 12:40:38PM +0200, Krzysztof Kozlowski wrote: >>> On Thu, Jun 11, 2026 at 02:44:56AM +0530, Mohit Dsor wrote: >>>> Add a new optional `lontium,port-select` property to describe the DSI >>>> input port configuration for the LT9611C variant, which supports >>>> single-port (A or B) and dual-port (A+B) operation. >>>> >>>> This property allows explicitly selecting the active DSI input port(s): >>>> 0 = port A (default) >>>> 1 = port B >>>> 2 = ports A and B (dual-port) >>>> >>>> Signed-off-by: Mohit Dsor <[email protected]> >>>> --- >>>> .../devicetree/bindings/display/bridge/lontium,lt9611.yaml | 13 >>>> +++++++++++++ >>>> 1 file changed, 13 insertions(+) >>>> >>>> diff --git >>>> a/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml >>>> b/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml >>>> index e0821a63d9d7..77220f893bf8 100644 >>>> --- a/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml >>>> +++ b/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml >>>> @@ -41,6 +41,17 @@ properties: >>>> vcc-supply: >>>> description: Regulator for 3.3V IO power. >>>> >>>> + lontium,port-select: >>>> + $ref: /schemas/types.yaml#/definitions/uint32 >>>> + enum: [0, 1, 2] >>>> + default: 0 >>>> + description: | >>>> + Selects which DSI input port(s) the bridge uses. Only relevant for >>>> + the lontium,lt9611c compatible. >>>> + 0 = PORT_SELECT_A - single DSI port A (default) >>>> + 1 = PORT_SELECT_B - single DSI port B >>>> + 2 = PORT_SELECT_AB - dual DSI ports A and B >>> >>> Why graph is not enough? Seems exactly duplicating the graph ports. >>> >>> Best regards, >>> Krzysztof >>> >> Hi Krzysztof, >> >> Thanks for the review. >> >> The graph describes the physical connectivity between endpoints, >> however it does not fully capture the internal mode of operation of >> the LT9611C. This variant supports multiple functional configurations >> (single-port A, single-port B, or dual-port A+B), which affect how the >> hardware internally combines or selects DSI inputs. >> >> In particular: >> - The graph can describe connections to both ports, but it does not >> indicate whether the device should operate in single-port or dual-port >> aggregation mode. >> - For single-port use, both ports may be described in DT for board >> consistency, while the driver still needs to know which port is >> actively selected. >> - Dual-port mode requires explicit configuration even when both >> endpoints are present in the graph. > > If both modes of operation are possible on a given board, then it sounds > like the mode should be selected at runtime, not hardcoded in the device > tree.
Yeah. Especially "while the driver still needs to know which port is actively selected" for a case when DT already clearly defines which ports are available, feels like 100% runtime decision, e.g. based on what is actually plugged into the connector. Best regards, Krzysztof
