From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756071Ab2DTR2y (ORCPT ); Fri, 20 Apr 2012 13:28:54 -0400 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:44985 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752137Ab2DTR2w (ORCPT ); Fri, 20 Apr 2012 13:28:52 -0400 Date: Fri, 20 Apr 2012 19:28:49 +0200 From: Johan Hovold To: Greg Kroah-Hartman Cc: Richard Purdie , Samuel Ortiz , Arnd Bergmann , Florian Tobias Schandinat , Andrew Morton , linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org Subject: Re: [PATCH 2/4] misc: add LM3533 ambient light sensor driver Message-ID: <20120420172849.GB12376@localhost> References: <1334935826-12527-1-git-send-email-jhovold@gmail.com> <1334935826-12527-3-git-send-email-jhovold@gmail.com> <20120420155734.GE8327@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120420155734.GE8327@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: boundary0_high boundary0_low boundary1_high boundary1_low boundary2_high boundary2_low boundary3_high boundary3_low gain target1_0 target1_1 target1_2 target1_3 target1_4 target2_0 target2_1 target2_2 target2_3 target2_4 target3_0 target3_1 target3_2 target3_3 target3_4 These define the "five light zones and three sets of corresponding brightness target levels" mentioned in the Kconfig entry and provides a gain setting. Each entry also corresponds to an 8-bit register, which is documented along with the overall ALS functionality in the datasheets (which will be published on the TI web page soon). So I think anyone integrating this IC (or anyone who has access to the datasheets) will have no problem with this interface, but I'd be happy to write something to put under Documentation as well. The end-customer insisted on sysfs configurability, but I'll probably add these settings to the platform data later as well. > 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. Thanks, Johan