From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:3192 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753224Ab0IET22 (ORCPT ); Sun, 5 Sep 2010 15:28:28 -0400 Message-ID: <4C83F0AF.9070603@redhat.com> Date: Sun, 05 Sep 2010 21:34:07 +0200 From: Hans de Goede MIME-Version: 1.0 To: Andy Walls CC: Jean-Francois Moine , linux-media@vger.kernel.org Subject: Re: [PATCH] LED control References: <20100904131048.6ca207d1@tele> <4C834D46.5030801@redhat.com> <20100905105627.0d5d3dab@tele> <4C83A12F.1070009@redhat.com> <1283712207.2057.77.camel@morgan.silverblock.net> In-Reply-To: <1283712207.2057.77.camel@morgan.silverblock.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit List-ID: Sender: Mauro Carvalho Chehab Hi, On 09/05/2010 08:43 PM, Andy Walls wrote: > On Sun, 2010-09-05 at 15:54 +0200, Hans de Goede wrote: >> Hi, >> >> On 09/05/2010 10:56 AM, Jean-Francois Moine wrote: >>> On Sun, 05 Sep 2010 09:56:54 +0200 >>> Hans de Goede wrote: >>> >>>> I think that using one control for both status leds (which is what we >>>> are usually talking about) and illuminator(s) is a bad idea. I'm fine >>>> with standardizing these, but can we please have 2 CID's one for >>>> status lights and one for the led. Esp, as I can easily see us >>>> supporting a microscope in the future where the microscope itself or >>>> other devices with the same bridge will have a status led, so then we >>>> will need 2 separate controls anyways. >>> >>> Hi Hans, >>> >>> I was not thinking about the status light (I do not see any other usage >>> for it), but well about illuminators which I saw only in microscopes. >>> >> >> Ah, ok thanks for clarifying. For some more on this see p.s. below. >> >>> So, which is the better name? V4L2_CID_LAMPS? V4L2_CID_ILLUMINATORS? >> >> I think that V4L2_CID_ILLUMINATORS together with a comment in the .h >> and explanation in the spec that this specifically applies to microscopes >> would be good. > > I concur with ILLUMINATORS. The word makes it very clear the control is > about actively putting light on a subject. A quick Goggle search shows > that the term 'illuminator" appears to apply to photography and IR > cameras as well. > > >> Regards, >> >> Hans >> >> p.s. >> >> I think it would be good to have a V4L2_CID_STATUS_LED too. In many drivers >> we are explicitly controlling the led by register writes. Some people may very >> well prefer the led to always be off. I know that uvc logitech cameras have >> controls for the status led through the extended uvc controls. Once we have >> a standardized LED control, we can move the logitech uvc cams over from >> using their own private one to this one. > > I saw two use cases mentioned for status LEDs: > > 1. always off > 2. driver automatically controls the LEDs. > > Can't that choice be handled with a module option Sure, just like all other v4l2 controls could be a module option, that is not very userfriendly though. , is there a case where > one needs more control? Not really. Regards, Hans