From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacek Anaszewski Subject: Re: [PATCH v3 1/2] dt: bindings: lm3692x: Add bindings for lm3692x LED driver Date: Thu, 16 Nov 2017 21:14:13 +0100 Message-ID: <82336eb7-2b89-d37b-d688-4e4302766346@gmail.com> References: <20171115194203.13572-1-dmurphy@ti.com> <0a78c883-f074-cc19-3c0c-fc05607400e9@ti.com> <20171115222323.GA18290@amd> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20171115222323.GA18290@amd> Sender: linux-leds-owner@vger.kernel.org To: Pavel Machek , Dan Murphy Cc: robh+dt@kernel.org, mark.rutland@arm.com, rpurdie@rpsys.net, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org, Lee Jones , Daniel Thompson , Jingoo Han List-Id: devicetree@vger.kernel.org Hi Dan and Pavel, On 11/15/2017 11:23 PM, Pavel Machek wrote: > Hi! > >>> Shouldn't the driver be targeted for backlight subsystem then? >>> >>> Adding backlight maintainers. >>> >> >> Great point! I was not aware of the backlight subsystem. >> >> Looks like I need to create a back light version as well. >> >> Like the lp8788 did since this can be used as a LED driver beyond >> display back lighting. > > No, definitely not two drivers for lp8788 hardware. I agree. > If that does not yet exist... you want to create glue layer to be able > to use LED as a display backlight. (It may already exist, no idea). > > ... > > Actually or maybe a LED trigger. Just set LED's trigger to "this is > display backlight". There is one already: drivers/leds/trigger/ledtrig-backlight.c It adds a LED class device to the fb_notifier_list (drivers/video/fbdev/core/fb_notify.c) using fb_register_client(). The same is used in backlight_device_register (drivers/video/backlight/backlight.c). Actually why do you want to have this driver in the LED subsystem, if it is advertised as "designed for LCD display backlighting"? As a side note I can say that I've been always wondering why the two subsystems for similar type of hardware. -- Best regards, Jacek Anaszewski