From: Mike Frysinger <vapier@gentoo.org>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: uclinux-dist-devel@blackfin.uclinux.org,
alsa-devel@alsa-project.org, Lars-Peter Clausen <lars@metafoo.de>,
device-drivers-devel@blackfin.uclinux.org,
Liam Girdwood <lrg@slimlogic.co.uk>
Subject: Re: [Device-drivers-devel] [uclinux-dist-devel] [PATCH 1/4] Blackfin: Use 8bit spi transfers for the ad1836
Date: Fri, 6 May 2011 09:12:34 -0400 [thread overview]
Message-ID: <BANLkTimDtzLgG10bV080kXYr8Ujh775pkA@mail.gmail.com> (raw)
In-Reply-To: <20110506124858.GA11701@sirena.org.uk>
On Fri, May 6, 2011 at 08:48, Mark Brown wrote:
> On Fri, May 06, 2011 at 02:28:32PM +0200, Lars-Peter Clausen wrote:
>> The snd_soc_cache infrastructure has several helper functions for writing spi
>> on a spi bus. The one used by the ad1836 was specifically added for the ad1836
>> and is special compared to the other spi helper functions in the regard that it
>> swaps the upper and the lower byte of the to be transferred data.
>> While this works on blackfin which is litte-endian this scheme will obviously
>> fail on big-endian machines. Also this might not work for other codecs which
>> want to reuse the same helper function.
>
> So clearly the cache stuff ought to be using cpu_to_be16 for this stuff.
> At present we've been lazy about this as on most CPUs the swap boils
> down to a noop. If we do end up needing both swaps then we just add
> this as another parameter in the cache infrastructure.
indeed ... this is the direction i'd rather head rather than drop all
the existing stuff down to 8bit only.
-mike
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next prev parent reply other threads:[~2011-05-06 13:12 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-05 17:52 [PATCH 1/4] Blackfin: Use 8bit spi transfers for the ad1836 Lars-Peter Clausen
2011-05-05 17:52 ` [PATCH 2/4] ASoC: Do not swap upper and lower byte in snd_soc_4_12_spi_write Lars-Peter Clausen
2011-05-05 17:52 ` [PATCH 3/4] ASoC: Get rid of snd_soc_*_*_spi_write wrapper functions Lars-Peter Clausen
2011-05-12 12:25 ` Barry Song
2011-05-05 17:52 ` [PATCH 4/4] ASoC: Use spi_write in do_spi_write Lars-Peter Clausen
2011-05-05 22:56 ` [uclinux-dist-devel] [PATCH 1/4] Blackfin: Use 8bit spi transfers for the ad1836 Mike Frysinger
2011-05-06 12:28 ` Lars-Peter Clausen
2011-05-06 12:48 ` Mark Brown
2011-05-06 13:12 ` Mike Frysinger [this message]
2011-05-06 13:19 ` Lars-Peter Clausen
2011-05-06 13:26 ` Mark Brown
2011-05-06 13:31 ` Lars-Peter Clausen
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