From: Lars-Peter Clausen <lars@metafoo.de>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Jonathan Cameron <jic23@cam.ac.uk>,
linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
patrick.vasseur@c-s.fr
Subject: Re: [PATCH v2] IIO ADC support for AD7923
Date: Tue, 12 Feb 2013 19:54:55 +0100 [thread overview]
Message-ID: <511A8FFF.8020807@metafoo.de> (raw)
In-Reply-To: <201302121710.r1CHAWES027406@localhost.localdomain>
On 02/12/2013 06:10 PM, Christophe Leroy wrote:
> This patch adds support for Analog Devices AD7923 ADC in the IIO Subsystem.
>
> Signed-off-by: Patrick Vasseur <patrick.vasseur@c-s.fr>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Looks good to me except for one small, but important issue.
[...]
> diff -urN linux-next-e347c98/drivers/iio/adc/ad7923.c linux-next-e347c98.new/drivers/iio/adc/ad7923.c
> --- linux-next-e347c98/drivers/iio/adc/ad7923.c 1970-01-01 01:00:00.000000000 +0100
> +++ linux-next-e347c98.new/drivers/iio/adc/ad7923.c 2013-02-12 15:16:29.000000000 +0100
[...]
> +
> +struct ad7923_state {
> + struct spi_device *spi;
> + struct spi_transfer ring_xfer[6];
I think 5 is the max number of transfers, one for each channel and one extra to
read the last result.
> + struct spi_transfer scan_single_xfer[2];
> + struct spi_message ring_msg;
> + struct spi_message scan_single_msg;
> + /*
> + * DMA (thus cache coherency maintenance) requires the
> + * transfer buffers to live in their own cache lines.
> + */
> + __be16 rx_buf[4] ____cacheline_aligned;
> + __be16 tx_buf[2];
The tx buffer also needs to be 4 elements.
> +};
[...]
next prev parent reply other threads:[~2013-02-12 18:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-12 17:10 [PATCH v2] IIO ADC support for AD7923 Christophe Leroy
2013-02-12 18:54 ` Lars-Peter Clausen [this message]
2013-02-13 6:47 ` leroy christophe
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