From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.irobotique.be ([92.243.18.41]:43792 "EHLO perceval.irobotique.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751582Ab0IMGnL (ORCPT ); Mon, 13 Sep 2010 02:43:11 -0400 From: Laurent Pinchart To: Andy Walls Subject: Re: [PATCH] LED control Date: Mon, 13 Sep 2010 08:43:52 +0200 Cc: Hans de Goede , "Jean-Francois Moine" , linux-media@vger.kernel.org References: <20100904131048.6ca207d1@tele> <4C83A12F.1070009@redhat.com> <1283712207.2057.77.camel@morgan.silverblock.net> In-Reply-To: <1283712207.2057.77.camel@morgan.silverblock.net> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201009130843.53344.laurent.pinchart@ideasonboard.com> List-ID: Sender: Hi Andy, On Sunday 05 September 2010 20:43:27 Andy Walls wrote: > On Sun, 2010-09-05 at 15:54 +0200, Hans de Goede wrote: > > 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, is there a case where > one needs more control? On Logitech UVC cameras, the status led can be set to - always on - always off - controlled by the camera - blinking (with a configurable frequency) -- Regards, Laurent Pinchart