From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760954AbdEWKmL (ORCPT ); Tue, 23 May 2017 06:42:11 -0400 Received: from galahad.ideasonboard.com ([185.26.127.97]:46393 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757457AbdEWKmJ (ORCPT ); Tue, 23 May 2017 06:42:09 -0400 From: Laurent Pinchart To: Tomi Valkeinen Cc: Peter Ujfalusi , airlied@linux.ie, jsarha@ti.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] drm/omap: displays: encoder-tpd12s015: Support for hot plug detection Date: Tue, 23 May 2017 13:42:25 +0300 Message-ID: <2146476.yg7iIlQTUW@avalon> User-Agent: KMail/4.14.10 (Linux/4.9.16-gentoo; KDE/4.14.32; x86_64; ; ) In-Reply-To: <7be9f55e-7d81-d9c8-9e30-1ddc284137e3@ti.com> References: <20170515090312.32051-1-peter.ujfalusi@ti.com> <8383085.j5ORBifRWg@avalon> <7be9f55e-7d81-d9c8-9e30-1ddc284137e3@ti.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Tomi, On Tuesday 23 May 2017 13:25:34 Tomi Valkeinen wrote: > On 23/05/17 12:48, Laurent Pinchart wrote: > > As the connector code can handle GPIO HPD thanks to patch 2/3, why does it > > have to be duplicated here ? I agree that encoders should support > > reporting of hotplug events when the HPD signal is connected to an > > encoder, but if it's connected to a GPIO, it seems to me that it should > > be the sole responsibility of the connector code to handle it. > > The HPD line goes from the connector to TPD12S015. From TPD12S015 > another line goes to the SoCs GPIO. Isn't it the same signal, just with glitches filtered ? The TPD12S015 is an ESD clamp, level shifter and DC-DC converter, if it wasn't for the two control inputs CT_CP_HPD and LS_OE, we could probably do without a driver. I wouldn't add HPD support to this driver, as the chip really can't detect HPD. -- Regards, Laurent Pinchart