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Date: Fri, 20 Apr 2012 10:37:54 -0700
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Johan Hovold <jhovold@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>, Samuel Ortiz <sameo@linux.intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Florian Tobias Schandinat <FlorianSchandinat@gmx.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org
Subject: Re: [PATCH 2/4] misc: add LM3533 ambient light sensor driver
Message-ID: <20120420173754.GA22222@kroah.com>
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On Fri, Apr 20, 2012 at 07:28:49PM +0200, Johan Hovold wrote:
> On Fri, Apr 20, 2012 at 08:57:34AM -0700, Greg Kroah-Hartman wrote:
> > On Fri, Apr 20, 2012 at 05:30:24PM +0200, Johan Hovold wrote:
> > > Add sub-driver for the ambient light sensor in National Semiconductor /
> > > TI LM3533 lighting power chips.
> > > 
> > > Raw ADC values as well as current ALS zone can be retrieved through
> > > sysfs. The ALS zone can also be read using a character device
> > > (/dev/lm3533-als) which is updated on zone changes (interrupt driven or
> > > polled).
> > > 
> > > The driver provides a configuration interface through sysfs.
> > 
> > Which seems to not be documented at all :(
> 
> There are the following sysfs entries for configuring ALS control:

<snip>

That's fine, but you need a Documentation/ABI entry for any new sysfs
file you create.
> > What about using the iio interface for this instead?  Doesn't that
> > already provide this standard interface you are looking for?
> 
> I had a look at iio last fall and decided not to use it at the time. I
> can't remember exactly what the reasons were right now, so I'll have
> to get back to you on this.

Please look into this, the iio framework is about to move out of the
staging tree for 3.5, so there should not be any reason for you to
create yet-another user api for this type of thing.

thanks,

greg k-h