From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-f67.google.com ([209.85.221.67]:41750 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726874AbfFIMXW (ORCPT ); Sun, 9 Jun 2019 08:23:22 -0400 Subject: Re: [PATCH v2 1/2] dt-bindings: Add docs for EL15203000 References: <20190607184022.13793-1-oleg@kaa.org.ua> <27c0b356-8111-6b36-23cc-8e654147178f@kaa.org.ua> <2eba86cb-01be-c002-32d0-80ab2ab14f97@gmail.com> <7e787498-537b-390d-589a-577f34ffbc3f@kaa.org.ua> From: Jacek Anaszewski Message-ID: <44b77942-232d-4b23-1da9-f59644492d74@gmail.com> Date: Sun, 9 Jun 2019 14:23:18 +0200 MIME-Version: 1.0 In-Reply-To: <7e787498-537b-390d-589a-577f34ffbc3f@kaa.org.ua> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: devicetree-owner@vger.kernel.org To: Oleh Kravchenko , Dan Murphy , devicetree@vger.kernel.org, linux-leds@vger.kernel.org List-ID: Hi Oleh, On 6/7/19 11:48 PM, Oleh Kravchenko wrote: > Jacek, > > 08.06.19 00:23, Jacek Anaszewski пише: >> Hi Oleh. >> >> On 6/7/19 11:17 PM, Oleh Kravchenko wrote: >>> Dan, >>> >>> On 08.06.19 00:04, Dan Murphy wrote: >>>> Oleh >>>> But this is not really max_brightness now this is a feature and now >>>> does not make sense in this context >>>>>> >>>>>> You may need to use something different for this property or expose >>>>>> a file in the driver. >>>>>> >>>>>> >>>>> Protocol for this board define 0x32 as brightness level. >>>>> This behaviur needed to keep backward compatibity. >>>>> >>>>> >>>> Backwards compatibility to what? >>> With old/new boards. >> >> You have in your driver the following: >> >> + * BRIGHTNESS    Can be 0x30 (OFF), 0x31 (ON). >> + *         0x32 (Effect) can be used for 0x50 (leaking) and >> + *         for 0x53 (blinking) >> >> If your max-brightness DT property is to be used for controlling this, >> then I don't see how it would be backward compatible with anything. >> >> Clearly, you don't need max-brightness DT property at all. > > What I should do with board which accept brightness in range 0x30 - 0x3a? > Where 0x3a means special effect. I believe 0x3a is a typo since above you have 0x32 for the effect. Anyway, we shouldn't propagate hardware design flaws to the userspace interface. You have ON/OFF register values for manipulating brightness, so use them appropriately. struct led_classdev's max_brightness property should be set to 1, as already pointed out by Dan. >> For blinking you can use blink_set op. To be able to recommend >> you anoptimal solution for the effect we would need more >> details regarding its nature. > > Thanks, I will do that. > But how to properly handle other effects? Not only blinking? For the effects we could probably use pattern trigger, but we need more information on how it can be configured. > And how to define it by device tree? > Driver can't get this information about what is really supported. > I don't want define effect code inside DT. We now have led-pattern DT property, which allows to initialize a LED with the DT provided pattern (see Documentation/devicetree/bindings/leds/common.txt). >>>> This is a new driver there should be no DT that has this compatible or >>>> definition. >>>> >>>> I will let Rob ack or nack this node. >>>> >>>> Dan >>>> >>> >>> >> > -- Best regards, Jacek Anaszewski