| Message ID | 20240126-dev-rx-enable-v5-3-5d934eda05ca@theobroma-systems.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v5,1/6] dt-bindings: serial: Add binding for rs485 receiver enable GPIO | expand |
On Fri, Jan 26, 2024 at 06:27:44PM +0100, Farouk Bouabid wrote: > RS485 can have a receiver-enable gpio (rx-enable-gpios). When rs485 is s/gpio/GPIO/ > enabled, this gpio, if provided, must be driven active while receiving. > However when RS485 is disabled this gpio should not have an undefined > state. In that case, as DE and RE pins can be connected both to this gpio, > if its state is not properly defined, can cause unexpected transceiver > behavior. > This binding depend on rx-enable-gpios to be implemented. Sounds like a constraint: dependencies: rs485-rx-enable-inactive-when-rs485-disabled: [ rx-enable-gpios ] > > Signed-off-by: Farouk Bouabid <farouk.bouabid@theobroma-systems.com> > --- > Documentation/devicetree/bindings/serial/rs485.yaml | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/Documentation/devicetree/bindings/serial/rs485.yaml b/Documentation/devicetree/bindings/serial/rs485.yaml > index b64577036b5c..4c79dfaaf460 100644 > --- a/Documentation/devicetree/bindings/serial/rs485.yaml > +++ b/Documentation/devicetree/bindings/serial/rs485.yaml > @@ -55,6 +55,11 @@ properties: > description: GPIO to handle a separate RS485 receive enable signal > maxItems: 1 > > + rs485-rx-enable-inactive-when-rs485-disabled: For something a bit shorter, perhaps: rs485-rx-enable-inactive-on-disable > + description: rx-enable GPIO is not active when RS485 is disabled. If missing, active-state > + is assumed. > + $ref: /schemas/types.yaml#/definitions/flag > + > rs485-term-gpios: > description: GPIO pin to enable RS485 bus termination. > maxItems: 1 > > -- > 2.34.1 >
diff --git a/Documentation/devicetree/bindings/serial/rs485.yaml b/Documentation/devicetree/bindings/serial/rs485.yaml index b64577036b5c..4c79dfaaf460 100644 --- a/Documentation/devicetree/bindings/serial/rs485.yaml +++ b/Documentation/devicetree/bindings/serial/rs485.yaml @@ -55,6 +55,11 @@ properties: description: GPIO to handle a separate RS485 receive enable signal maxItems: 1 + rs485-rx-enable-inactive-when-rs485-disabled: + description: rx-enable GPIO is not active when RS485 is disabled. If missing, active-state + is assumed. + $ref: /schemas/types.yaml#/definitions/flag + rs485-term-gpios: description: GPIO pin to enable RS485 bus termination. maxItems: 1
RS485 can have a receiver-enable gpio (rx-enable-gpios). When rs485 is enabled, this gpio, if provided, must be driven active while receiving. However when RS485 is disabled this gpio should not have an undefined state. In that case, as DE and RE pins can be connected both to this gpio, if its state is not properly defined, can cause unexpected transceiver behavior. This binding depend on rx-enable-gpios to be implemented. Signed-off-by: Farouk Bouabid <farouk.bouabid@theobroma-systems.com> --- Documentation/devicetree/bindings/serial/rs485.yaml | 5 +++++ 1 file changed, 5 insertions(+)