From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp-vbr7.xs4all.nl ([194.109.24.27]:4726 "EHLO smtp-vbr7.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751880AbaBMJv1 (ORCPT ); Thu, 13 Feb 2014 04:51:27 -0500 Message-ID: <52FC94C0.5000904@xs4all.nl> Date: Thu, 13 Feb 2014 10:47:44 +0100 From: Hans Verkuil MIME-Version: 1.0 To: Laurent Pinchart CC: linux-media@vger.kernel.org, Hans Verkuil , Lars-Peter Clausen Subject: Re: [PATCH 43/47] adv7604: Control hot-plug detect through a GPIO References: <1391618558-5580-1-git-send-email-laurent.pinchart@ideasonboard.com> <1391618558-5580-44-git-send-email-laurent.pinchart@ideasonboard.com> <52F9F6DB.1080700@xs4all.nl> <1637754.DCKyOCpBtn@avalon> In-Reply-To: <1637754.DCKyOCpBtn@avalon> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 02/11/14 13:03, Laurent Pinchart wrote: > Hi Hans, > > On Tuesday 11 February 2014 11:09:31 Hans Verkuil wrote: >> On 02/05/14 17:42, Laurent Pinchart wrote: >>> Replace the ADV7604-specific hotplug notifier with a GPIO to control the >>> HPD pin directly instead of going through the bridge driver. >> >> Hmm, that's not going to work for me. I don't have a GPIO pin here, instead >> it is a bit in a register that I have to set. > > But that bit controls a GPIO, doesn't it ? In that case it should be exposed > as a GPIO controller. I feel unhappy about losing this notifier for two reasons: first adding a GPIO controller just to toggle a bit adds 40 lines to my driver, and that doesn't sit well with me. It's basically completely unnecessary overhead. The second reason is that in some cases you want to do something in addition to just toggling the hotplug pin. In particular for CEC support this could be quite useful. In fact, if the adv7604 supports the ARC feature (Audio Return Channel), then this is really needed because in that case the hotplug toggling would have to be done via CEC CDC commands. However, while this webpage claims that the ARC is supported, I can't find any other information about that. http://www.analog.com/en/audiovideo-products/analoghdmidvi-interfaces/adv7604/products/product.html Lars-Peter, do you know anything about ARC support in the adv7604? Regards, Hans