From: David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
To: Mark Jackson <mpfj-kZtEnBLzDKq1Qrn1Bg8BZw@public.gmane.org>
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
Alessandro Zummo
<alessandro.zummo-BfzFCNDTiLLj+vYz1yj4TQ@public.gmane.org>,
lkml <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
Subject: Re: [PATCH] Add Dallas DS1390 RTC chip
Date: Fri, 17 Oct 2008 08:29:06 -0700 [thread overview]
Message-ID: <200810170829.06699.david-b@pacbell.net> (raw)
In-Reply-To: <48F8467C.5010902-kZtEnBLzDKq1Qrn1Bg8BZw@public.gmane.org>
On Friday 17 October 2008, Mark Jackson wrote:
> >> + /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
> >> + xfer.tx_buf = chip->tx_buf;
> >> + xfer.rx_buf = chip->rx_buf;
> >
> > you use the same buffer a few functions below. either
> > one way or the other. please investigate with the spi subsystem maintainer.
>
> David,
>
> Just to double check (as per Alessandro's suggestion), is this okay use of the
> spi buffers ?
Yes. That comment deserves to be updated.
SPI does bi-directional I/O, and the underlying controller
should be able to just replace the contents of a buffer
with a spi_transfer that uses the same rx and tx buffers.
- Dave
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next prev parent reply other threads:[~2008-10-17 15:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <48F452BE.2030901@mimc.co.uk>
[not found] ` <20081014101703.1ded0259@i1501.lan.towertech.it>
2008-10-17 8:02 ` [PATCH] Add Dallas DS1390 RTC chip Mark Jackson
[not found] ` <48F8467C.5010902-kZtEnBLzDKq1Qrn1Bg8BZw@public.gmane.org>
2008-10-17 15:29 ` David Brownell [this message]
[not found] ` <200810170829.06699.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-10-17 18:57 ` Mark Jackson
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