[alsa-devel] [PATCH] [ALSA] Allow setting codec register with sys filesystem

Takashi Iwai tiwai at suse.de
Mon Oct 6 12:03:32 CEST 2008


At Mon, 6 Oct 2008 10:58:57 +0100,
Mark Brown wrote:
> 
> On Sat, Oct 04, 2008 at 04:54:09PM -0700, Troy Kisky wrote:
> > i.e. echo 6 59 >/sys/devices/platform/soc-audio.0/codec_reg
> > will set register 0x06 to a value of 0x59
> 
> > Signed-off-by: Troy Kisky <troy.kisky at boundarydevices.com>
> 
> I'd probably take a patch to do this in debugfs but I don't think it is
> appropriate to do this in sysfs.  Writing to the registers outside the
> control of the drivers can seriously interfere with their operation and
> confuse user space - it's something you can get away with if you know
> what you're doing but it's not something that should be available as a
> standard, advertised interface.  There's also the possibility of the
> driver trampling over any settings made with this interface which
> wouldn't be helpful either.

Putting into debugfs sounds like a saner option, as this is only for
debugging.

OTOH, symmetrical read/write operations also good.
Will be the sysfs register show op moved to debugfs, too?


thanks,

Takashi


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