From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Murphy Subject: Re: [PATCH v4 2/7] dt-bindings: ti-lmu: Modify dt bindings for the LM3697 Date: Thu, 25 Oct 2018 13:07:25 -0500 Message-ID: References: <20181023170623.31820-1-dmurphy@ti.com> <20181023170623.31820-2-dmurphy@ti.com> <20181024090421.GB24997@amd> <20181024145434.GC9327@bogus> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181024145434.GC9327@bogus> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Rob Herring Cc: Pavel Machek , jacek.anaszewski@gmail.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org, lee.jones@linaro.org, tony@atomide.com List-Id: devicetree@vger.kernel.org Rob On 10/24/2018 09:54 AM, Rob Herring wrote: > On Wed, Oct 24, 2018 at 07:07:57AM -0500, Dan Murphy wrote: >> Pavel >> >> On 10/24/2018 04:04 AM, Pavel Machek wrote: >>> Hi! >>> >>>> The LM3697 is a single function LED driver. The single function LED >>>> driver needs to reside in the LED directory as a dedicated LED driver >>>> and not as a MFD device. The device does have common brightness and ramp >>> >>> So it is single function LED driver. That does not mean it can not >>> share bindings with the rest. Where the bindings live is not imporant. >>> >> >> It can share bindings that are correctly done, not ones that are incomplete and incorrect. >> >> Where bindings live is important to new Linux kernel developers and product >> developers looking for the proper documentation on the H/W bindings. >> >>>> reside in the Documentation/devicetree/bindings/leds directory and follow the >>>> current LED and general bindings guidelines. >>> >>> What you forgot to tell us in the changelog: >> >> I can add this to the changelog. >> >>> >>>> +Optional child properties: >>>> + - runtime-ramp-up-msec: Current ramping from one brightness level to >>>> + the a higher brightness level. >>>> + Range from 2048 us - 117.44 s >>> >>> The other binding uses "ramp-up-msec". Tell us why you are changing this, or >>> better don't change things needlessly. >>> >>> We don't want to be using "runtime-ramp-up-msec" for one device and >>> "ramp-up-msec" for the other. >> >> This is another example of how the original bindings were incorrect and misleading. >> >> The LM3697 have 2 ramp implementations that can be used. >> >> Startup/Shutdown ramp and Runtime Ramp. Same Ramp rates different registers and >> different end user experience. >> >> So having a single node call ramp-up-msec is misleading and it does not >> indicate what the H/W will do. > > The existing ones aren't documented (present in the example is not > documented). This seems like something that should be common rather than > TI specific. Though it also seems more like something the user would > want to control (i.e. sysfs) rather than fixed in DT. > Changing the runtime ramping or startup/shutdown ramping could also be done via sysfs. I am not dedicated to having it in the DT file I was following prior art. Jacek Do you have an opinion on this? Dan > Rob > -- ------------------ Dan Murphy