From: David Lechner <dlechner@baylibre.com>
To: nuno.sa@analog.com
Cc: linux-iio@vger.kernel.org, Lars-Peter Clausen <lars@metafoo.de>,
Michael Hennerich <Michael.Hennerich@analog.com>,
Jonathan Cameron <jic23@kernel.org>
Subject: Re: [PATCH] iio: adc: ad9467: use DMA safe buffer for spi
Date: Tue, 7 May 2024 16:43:18 -0500 [thread overview]
Message-ID: <CAMknhBHf5f_z9iG89sfHOZ5F_q+Ho+zKDXA0M10U3BBMuSUh0w@mail.gmail.com> (raw)
In-Reply-To: <20240506-dev-ad9467-dma-v1-1-e5c31b464e8f@analog.com>
On Mon, May 6, 2024 at 9:55 AM Nuno Sa via B4 Relay
<devnull+nuno.sa.analog.com@kernel.org> wrote:
>
> From: Nuno Sa <nuno.sa@analog.com>
>
> Make sure we use a DMA safe buffer (IIO_DMA_MINALIGN) for all the spi
> transfers.
>
> Note that as we noe use a shared buffer, lock guards had to be added
s/noe/now
> accordingly.
>
> Fixes: ad6797120238 ("iio: adc: ad9467: add support AD9467 ADC")
> Signed-off-by: Nuno Sa <nuno.sa@analog.com>
> ---
> drivers/iio/adc/ad9467.c | 87 ++++++++++++++++++++++++------------------------
> 1 file changed, 44 insertions(+), 43 deletions(-)
>
> diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c
> index e85b763b9ffcb..368546b032891 100644
> --- a/drivers/iio/adc/ad9467.c
> +++ b/drivers/iio/adc/ad9467.c
> @@ -141,55 +141,55 @@ struct ad9467_state {
> struct gpio_desc *pwrdown_gpio;
> /* ensure consistent state obtained on multiple related accesses */
> struct mutex lock;
> + union {
> + u8 buf[3];
> + u8 tbuf[2];
> + u8 rbuf[1];
> + } __aligned(IIO_DMA_MINALIGN);
> };
>
> -static int ad9467_spi_read(struct spi_device *spi, unsigned int reg)
> +static int ad9467_spi_read(struct ad9467_state *st, unsigned int reg)
> {
> - unsigned char tbuf[2], rbuf[1];
> int ret;
>
> - tbuf[0] = 0x80 | (reg >> 8);
> - tbuf[1] = reg & 0xFF;
> + st->tbuf[0] = 0x80 | (reg >> 8);
> + st->tbuf[1] = reg & 0xFF;
>
> - ret = spi_write_then_read(spi,
> - tbuf, ARRAY_SIZE(tbuf),
> - rbuf, ARRAY_SIZE(rbuf));
> + ret = spi_write_then_read(st->spi, st->tbuf, ARRAY_SIZE(st->tbuf),
> + st->rbuf, ARRAY_SIZE(st->rbuf));
spi_write_then_read() copies the buffers, so technically we don't need
to change this one.
>
> if (ret < 0)
> return ret;
>
> - return rbuf[0];
> + return st->rbuf[0];
> }
>
prev parent reply other threads:[~2024-05-07 21:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 14:55 [PATCH] iio: adc: ad9467: use DMA safe buffer for spi Nuno Sa via B4 Relay
2024-05-07 21:43 ` David Lechner [this message]
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