From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacek Anaszewski Subject: Re: [PATCH v3 3/4] leds: core: add documentation for color extension Date: Fri, 19 Feb 2016 14:59:20 +0100 Message-ID: <56C71FB8.1060006@samsung.com> References: <56C637D2.1090805@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mailout2.w1.samsung.com ([210.118.77.12]:45803 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1425967AbcBSN7W (ORCPT ); Fri, 19 Feb 2016 08:59:22 -0500 Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout2.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0O2S004NBS6X0U60@mailout2.w1.samsung.com> for linux-leds@vger.kernel.org; Fri, 19 Feb 2016 13:59:21 +0000 (GMT) In-reply-to: <56C637D2.1090805@gmail.com> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: Heiner Kallweit Cc: linux-leds@vger.kernel.org Hi Heiner, On 02/18/2016 10:29 PM, Heiner Kallweit wrote: > Document the color extension in Documentation/leds/leds-class.txt > > Signed-off-by: Heiner Kallweit > --- > v2: > - introduced to patch series > v3: > - document extension in more detail > --- > Documentation/leds/leds-class.txt | 24 +++++++++++++++++++----- > 1 file changed, 19 insertions(+), 5 deletions(-) > > diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt > index d406d98..d4bf9c1 100644 > --- a/Documentation/leds/leds-class.txt > +++ b/Documentation/leds/leds-class.txt > @@ -8,6 +8,19 @@ LED is defined in max_brightness file. The brightness file will set the brightne > of the LED (taking a value 0-max_brightness). Most LEDs don't have hardware > brightness support so will just be turned on for non-zero brightness settings. > > +If a driver uses the colour extension of the LED core then the brightness > +file can be used to set hue / saturation / value. The brightness value is > +interpreted as: <0000000F> > +Usage of the least byte is identical to monochrome mode. Saturation can be > +0-255 and hue 0-251 (Colour circle is mapped to 0-252). > +If hue and saturation both are 0 the current colour is not changed and only > +the brightness is set. This ensures backwards compatibility with monochrome > +mode, e.g. in calls like led_set_brightness(LED_FULL). > +This behavior can be overridden with flag F (LED_SET_COLOR). If this flag > +is set then hue and saturation are not checked for being 0 and the color > +components are set unconditionally. Example: > +0x010000ff sets the LED to white color with full brightness. When asking for justifying the need for the flag, I had on mind an explanation of why the flag is needed any not only what are the implications of setting it. My intention was rather to provide a simple use case example, e.g. temperature monitoring, when brightness is set through the trigger, with preset hue and saturation - if I understood properly your idea. > + > The class also introduces the optional concept of an LED trigger. A trigger > is a kernel based source of led events. Triggers can either be simple or > complex. A simple trigger isn't configurable and is designed to slot into > @@ -45,11 +58,12 @@ Is currently of the form: > > "devicename:colour:function" > > -There have been calls for LED properties such as colour to be exported as > -individual led class attributes. As a solution which doesn't incur as much > -overhead, I suggest these become part of the device name. The naming scheme > -above leaves scope for further attributes should they be needed. If sections > -of the name don't apply, just leave that section blank. > +If the colour extension is used hsv / rgb can be used instead of a specific > +colour. There have been calls for LED properties such as colour to be > +exported as individual led class attributes. As a solution which doesn't > +incur as much overhead, I suggest these become part of the device name. > +The naming scheme above leaves scope for further attributes should they be > +needed. If sections of the name don't apply, just leave that section blank. > > > Brightness setting API > -- Best regards, Jacek Anaszewski