Messages in this thread | | | Date | Thu, 12 Oct 2023 20:35:59 +0200 | From | m.brock@vanmierl ... | Subject | Re: [PATCH V2 1/2] dt-bindings: Add optional gpio property to uartps node to support rs485 |
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Manikanta Guntupalli wrote on 2023-10-11 16:56: > Add optional gpio property to uartps node and reference to rs485.yaml > > On Xilinx/AMD Kria SOM KD240 board rs485 connects via TI ISOW1432 > Transceiver device, where one GPIO is used for driving DE/RE signals. > With rs485 half duplex configuration, DE and RE shorts to each other,
s/shorts/are connected
> and at a time, any node acts as either a driver or a receiver. > > Here, > DE - Driver enable. If pin is floating, driver is disabled. > RE - Receiver enable. If pin is floating, receiver buffer is disabled.
Please use DE and /RE to indicate DE is active high and /RE is active low.
> xlnx,phy-ctrl-gpios is optional property, because it is not required > for uart console node.
How about introducing an rs485 generic gpios property instead of xlnx private one? See also rs485-term-gpios and rs485-rx-during-tx-gpios.
Also note that every kernel driver expects to use RTS for this purpose. So why not give this driver the option to choose a gpio instead of its native RTS? And from there on use the rts route? What if someone wants to use normal (non-rs485) RTS on a GPIO instead of the native pin?
@Rob Herring I am curious to know how the rs485 maintainers look at this.
Maarten
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