From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from oyp.chewa.net ([91.121.6.101]:35872 "EHLO oyp.chewa.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754556Ab2EVQ0l convert rfc822-to-8bit (ORCPT ); Tue, 22 May 2012 12:26:41 -0400 From: "=?iso-8859-1?q?R=E9mi?= Denis-Courmont" To: Antti Palosaari Subject: Re: RFC: V4L2 API and radio devices with multiple tuners Date: Tue, 22 May 2012 19:26:37 +0300 Cc: Hans de Goede , Linux Media Mailing List , Hans Verkuil , Ondrej Zary References: <4FB7E489.10803@redhat.com> <4FB7E827.7070701@iki.fi> In-Reply-To: <4FB7E827.7070701@iki.fi> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Message-Id: <201205221926.38970.remi@remlab.net> Sender: linux-media-owner@vger.kernel.org List-ID: Le samedi 19 mai 2012 21:36:23 Antti Palosaari, vous avez écrit : > On 19.05.2012 21:20, Hans de Goede wrote: > > Currently the V4L2 API does not allow for radio devices with more then 1 > > tuner, > > which is a bit of a historical oversight, since many radio devices have 2 > > tuners/demodulators 1 for FM and one for AM. Trying to model this as 1 > > tuner > > really does not work well, as they have 2 completely separate frequency > > bands > > they handle, as well as different properties (the FM part usually is > > stereo capable, the AM part is not). > > > > It is important to realize here that usually the AM/FM tuners are part > > of 1 chip, and often have only 1 frequency register which is used in > > both AM/FM modes. IOW it more or less is one tuner, but with 2 modes, > > and from a V4L2 API pov these modes are best modeled as 2 tuners. > > This is at least true for the radio-cadet card and the tea575x, > > which are the only 2 AM capable radio devices we currently know about. > > For DVB API we changed just opposite direction - from multi-frontend to > single-frontend. I think one device per one standard is good choice. If I understand Hans correctly, he suggests to use two tuners on a *single* radio device node, much like a single video device nodes can have multiple video inputs. So I think you agree with Hans, and so do I. -- Rémi Denis-Courmont http://www.remlab.net/ http://fi.linkedin.com/in/remidenis