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Message-ID: <0ec567d7df3632a9c8104485c4207a47e159fdb9.camel@gmail.com>
Subject: Re: [PATCH v2 5/5] iio: adc: ad7380: use spi_optimize_message()
From: Nuno =?ISO-8859-1?Q?S=E1?= <noname.nuno@gmail.com>
To: David Lechner <dlechner@baylibre.com>, Mark Brown <broonie@kernel.org>
Cc: Martin Sperl <kernel@martin.sperl.org>, David Jander
 <david@protonic.nl>,  Jonathan Cameron <jic23@kernel.org>, Michael
 Hennerich <michael.hennerich@analog.com>, Nuno =?ISO-8859-1?Q?S=E1?=
 <nuno.sa@analog.com>, Alain Volmat <alain.volmat@foss.st.com>, Maxime
 Coquelin <mcoquelin.stm32@gmail.com>, Alexandre Torgue
 <alexandre.torgue@foss.st.com>,  linux-spi@vger.kernel.org,
 linux-kernel@vger.kernel.org,  linux-stm32@st-md-mailman.stormreply.com,
 linux-arm-kernel@lists.infradead.org,  linux-iio@vger.kernel.org, Julien
 Stephan <jstephan@baylibre.com>
Date: Tue, 20 Feb 2024 11:41:29 +0100
In-Reply-To: <20240219-mainline-spi-precook-message-v2-5-4a762c6701b9@baylibre.com>
References: 
	<20240219-mainline-spi-precook-message-v2-0-4a762c6701b9@baylibre.com>
	 <20240219-mainline-spi-precook-message-v2-5-4a762c6701b9@baylibre.com>
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On Mon, 2024-02-19 at 16:33 -0600, David Lechner wrote:
> This modifies the ad7380 ADC driver to use spi_optimize_message() to
> optimize the SPI message for the buffered read operation. Since buffered
> reads reuse the same SPI message for each read, this can improve
> performance by reducing the overhead of setting up some parts the SPI
> message in each spi_sync() call.
>=20
> Signed-off-by: David Lechner <dlechner@baylibre.com>
> ---
>=20

Reviewed-by: Nuno Sa <nuno.sa@analog.com>

> v2 changes:
> - Removed dynamic allocation of spi xfer/msg
> - Moved spi message optimization to probe function
> - Dropped buffer pre/post callbacks
>=20
> =C2=A0drivers/iio/adc/ad7380.c | 36 ++++++++++++++++++++++++++++++------
> =C2=A01 file changed, 30 insertions(+), 6 deletions(-)
>=20
> diff --git a/drivers/iio/adc/ad7380.c b/drivers/iio/adc/ad7380.c
> index abd746aef868..6b3fd20c8f1f 100644
> --- a/drivers/iio/adc/ad7380.c
> +++ b/drivers/iio/adc/ad7380.c
> @@ -133,6 +133,9 @@ struct ad7380_state {
> =C2=A0	struct spi_device *spi;
> =C2=A0	struct regulator *vref;
> =C2=A0	struct regmap *regmap;
> +	/* xfer and msg for buffer reads */
> +	struct spi_transfer xfer;
> +	struct spi_message msg;
> =C2=A0	/*
> =C2=A0	 * DMA (thus cache coherency maintenance) requires the
> =C2=A0	 * transfer buffers to live in their own cache lines.
> @@ -236,14 +239,9 @@ static irqreturn_t ad7380_trigger_handler(int irq, v=
oid *p)
> =C2=A0	struct iio_poll_func *pf =3D p;
> =C2=A0	struct iio_dev *indio_dev =3D pf->indio_dev;
> =C2=A0	struct ad7380_state *st =3D iio_priv(indio_dev);
> -	struct spi_transfer xfer =3D {
> -		.bits_per_word =3D st->chip_info->channels[0].scan_type.realbits,
> -		.len =3D 4,
> -		.rx_buf =3D st->scan_data.raw,
> -	};
> =C2=A0	int ret;
> =C2=A0
> -	ret =3D spi_sync_transfer(st->spi, &xfer, 1);
> +	ret =3D spi_sync(st->spi, &st->msg);
> =C2=A0	if (ret)
> =C2=A0		goto out;
> =C2=A0
> @@ -335,6 +333,28 @@ static const struct iio_info ad7380_info =3D {
> =C2=A0	.debugfs_reg_access =3D &ad7380_debugfs_reg_access,
> =C2=A0};
> =C2=A0
> +static void ad7380_unoptimize_spi_msg(void *msg)
> +{
> +	spi_unoptimize_message(msg);
> +}
> +
> +static int devm_ad7380_setup_spi_msg(struct device *dev, struct ad7380_s=
tate *st)
> +{
> +	int ret;
> +
> +	st->xfer.bits_per_word =3D st->chip_info->channels[0].scan_type.realbit=
s;
> +	st->xfer.len =3D 4;
> +	st->xfer.rx_buf =3D st->scan_data.raw;
> +
> +	spi_message_init_with_transfers(&st->msg, &st->xfer, 1);
> +
> +	ret =3D spi_optimize_message(st->spi, &st->msg);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to optimize message\n");
> +
> +	return devm_add_action_or_reset(dev, ad7380_unoptimize_spi_msg, &st->ms=
g);
> +}
> +
> =C2=A0static int ad7380_init(struct ad7380_state *st)
> =C2=A0{
> =C2=A0	int ret;
> @@ -411,6 +431,10 @@ static int ad7380_probe(struct spi_device *spi)
> =C2=A0		return dev_err_probe(&spi->dev, PTR_ERR(st->regmap),
> =C2=A0				=C2=A0=C2=A0=C2=A0=C2=A0 "failed to allocate register map\n");
> =C2=A0
> +	ret =3D devm_ad7380_setup_spi_msg(&spi->dev, st);
> +	if (ret)
> +		return ret;
> +
> =C2=A0	indio_dev->channels =3D st->chip_info->channels;
> =C2=A0	indio_dev->num_channels =3D st->chip_info->num_channels;
> =C2=A0	indio_dev->name =3D st->chip_info->name;
>=20