linux-kernel - Re: [PATCH 1/5] spi: add spi_optimize

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Date: Tue, 13 Feb 2024 18:55:00 +0000
From: Mark Brown <broonie@...nel.org>
To: David Lechner <dlechner@...libre.com>
Cc: Martin Sperl <kernel@...tin.sperl.org>,
	David Jander <david@...tonic.nl>,
	Jonathan Cameron <jic23@...nel.org>,
	Michael Hennerich <michael.hennerich@...log.com>,
	Nuno Sá <nuno.sa@...log.com>,
	Alain Volmat <alain.volmat@...s.st.com>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Alexandre Torgue <alexandre.torgue@...s.st.com>,
	linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-kernel@...ts.infradead.org, linux-iio@...r.kernel.org
Subject: Re: [PATCH 1/5] spi: add spi_optimize_message() APIs

On Mon, Feb 12, 2024 at 05:26:41PM -0600, David Lechner wrote:

> This adds a new spi_optimize_message() function that can be used to
> optimize SPI messages that are used more than once. Peripheral drivers
> that use the same message multiple times can use this API to perform SPI
> message validation and controller-specific optimizations once and then
> reuse the message while avoiding the overhead of revalidating the
> message on each spi_(a)sync() call.

This looks basically fine.  Some small comments:

> +/**
> + * __spi_unoptimize_message - shared implementation of spi_unoptimize_message()
> + *                            and spi_maybe_unoptimize_message()
> + * @msg: the message to unoptimize

There's no need for kerneldoc for internal only functions and it can
make the generated documentation a bit confusing for users.  Just skip
the /** for /*.

> +static int __spi_optimize_message(struct spi_device *spi,
> +				  struct spi_message *msg,
> +				  bool pre_optimized)
> +{
> +	struct spi_controller *ctlr = spi->controller;
> +	int ret;
> +
> +	ret = __spi_validate(spi, msg);
> +	if (ret)
> +		return ret;
> +
> +	if (ctlr->optimize_message) {
> +		ret = ctlr->optimize_message(msg);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	msg->pre_optimized = pre_optimized;

It would probably be clearer to name the parameter pre_optimising rather
than pre_optimized, as it is the logic is a bit confusing.  Either that
or some comments.  A similar issue applies on the cleanup path.

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