Re: [PATCH 2/7] dt-bindings: serial: Add the line transceiver enable GPIO

[sashiko-bot@kernel.org]

> A UART's line transceiver (RS-232, RS-485, an isolated or a
> multiprotocol part) is a dumb device with no node of its own, yet on
> many boards it is the largest consumer behind the port and can be
> switched off, through a shutdown input of the part or a switch in its
> supply. Device trees have no way to say so, and the transceiver stays
> powered for as long as the system is up, whether or not the port is
> open.
> 
> Add transceiver-enable-gpios, the GPIO that turns the transceiver on,
> as a property of the UART node alongside the transceiver pins that
> rs485.yaml already describes, and transceiver-startup-delay-us for the
> time the part needs to become operational: a transceiver that
> generates its own supplies behind a shutdown input can take a
> millisecond until they are up. The GPIO belongs to one port; on a
> multi-port controller it is a property of the port's child node. A
> serial device with a driver of its own, such as a Bluetooth module,
> remains a child node of the UART.
> 
> Signed-off-by: Tapio Reijonen <tapio.reijonen@vaisala.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261111-serial-transceiver-supply-v1-0-40bad0f912f2@vaisala.com?part=2