From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161210AbdKQSDc (ORCPT ); Fri, 17 Nov 2017 13:03:32 -0500 Received: from fllnx210.ext.ti.com ([198.47.19.17]:45101 "EHLO fllnx210.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753307AbdKQSDW (ORCPT ); Fri, 17 Nov 2017 13:03:22 -0500 Subject: Re: [PATCH v3 1/2] dt: bindings: lm3692x: Add bindings for lm3692x LED driver To: Jingoo Han , "'Pavel Machek'" CC: "'Jacek Anaszewski'" , , , , , , , "'Lee Jones'" , "'Daniel Thompson'" References: <20171115194203.13572-1-dmurphy@ti.com> <0a78c883-f074-cc19-3c0c-fc05607400e9@ti.com> <20171115222323.GA18290@amd> <82336eb7-2b89-d37b-d688-4e4302766346@gmail.com> <16189eab-5541-9550-c027-1c9d2b5fa6d7@ti.com> <20171117112032.GA13855@amd> <000b01d35fc1$57ad0500$07070f00$@gmail.com> From: Dan Murphy Message-ID: <17b8e1ce-092a-0449-4733-533162b26499@ti.com> Date: Fri, 17 Nov 2017 12:02:39 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <000b01d35fc1$57ad0500$07070f00$@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Pavel and Jacek On 11/17/2017 10:30 AM, Jingoo Han wrote: > On Friday, November 17, 2017 6:21 AM, Pavel Machek wrote: >> >> Hi! >> >>>>> 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"? >>> >>> Well this is also advertised as a driver for Smart phone and tablet >> devices. And having worked with the Android lighting >>> solutions this is the preferred subsystem for Android. The Android OS >> manages the led brightness based on ALS values and in >>> turn calls into the driver to control the brightness register through >> the vendor provided lighting HAL. >>> >> >> Well.. if it can control other LEDs than just backlight, I believe it >> can stay in the LED subsystem. > > I also agree with your opinion. I will make the necessary changes for v4. Just a heads up I won't be posting v4 until after the US holiday so you don't think I abandoned everything. Dan > > Best regards, > Jingoo Han > >> >>> I am going to look at the backlight source to figure out how to get the >> same functionality using the backlight subsystem. >>> Otherwise I will plug in this driver to the backlight subsystem through >> the notifier. >>> >> >> The backlight trigger should be ok. >> >> Best regards, >> > Pavel >> -- >> (english) http://www.livejournal.com/~pavelmachek >> (cesky, pictures) >> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html > -- ------------------ Dan Murphy