Re: [PATCH v4 3/6] dt-bindings: serial: add binding for rs485 rx-enable state when rs485 is disabled

From: Quentin Schulz
Date: Mon Jan 29 2024 - 07:27:11 EST


Hi Conor,

On 1/28/24 18:38, Conor Dooley wrote:
On Fri, Jan 26, 2024 at 03:55:12PM +0100, Farouk Bouabid wrote:
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.

Why do you need a dedicated property for this when there exists a device
specific compatible for the uart on both of the affected rockchip
systems?


This has nothing to do with Rockchip's IP but the HW design of our carrierboard, so using the "rockchip,px30-uart" for that (which I assume is what was suggested here?) is incorrect since it'll also apply to PX30, RK3399 and RK3588-based Q7 SoCs we manufacture.

Did I understand the suggestion correctly?

Cheers,
Quentin