Re: [PATCH v7 7/9] serial: max310x: schedule tx_work directly from the IRQ handler

[sashiko-bot@kernel.org]

> The TXEMPTY interrupt asks for a FIFO refill, and start_tx() does
> nothing beyond scheduling tx_work, so going through it makes no
> functional difference. It does conflate two distinct events, though:
> start_tx() is the serial core starting a new transmission, while
> TXEMPTY can only fire for a transmission that is already running -
> the bit latches on the FIFO's non-empty to empty transition, and the
> IRQ handler's read of IRQSTS consumes the latch, so a stale TXEMPTY
> cannot exist on an idle port (if the bit were level-triggered, the
> handler's read-until-clear loop would never terminate).
> 
> Schedule tx_work directly, keeping the interrupt path a pure FIFO
> refill. This is preparation for a following patch that adds
> software-timed RS485 RTS control, where start_tx() also starts the
> RTS envelope and a refill must not restart it.
> 
> No functional change.
> 
> Assisted-by: Claude:claude-fable-5
> Signed-off-by: Tapio Reijonen <tapio.reijonen@vaisala.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261005-max310x-rs485-sw-delay-v7-0-6ae392eca08c@vaisala.com?part=7