From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: Re: [PATCH] OMAP: DSS2: DSI: Support non-dcs long read Date: Fri, 05 Aug 2011 10:53:07 +0300 Message-ID: <1312530787.1907.28.camel@deskari> References: <1309405483-6876-1-git-send-email-arve@android.com> <1312459611.2143.18.camel@deskari> <1312528148.1907.13.camel@deskari> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from na3sys009aog113.obsmtp.com ([74.125.149.209]:36863 "EHLO na3sys009aog113.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750881Ab1HEHxM (ORCPT ); Fri, 5 Aug 2011 03:53:12 -0400 Received: by mail-fx0-f54.google.com with SMTP id 4so5667444fxe.27 for ; Fri, 05 Aug 2011 00:53:10 -0700 (PDT) In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Arve =?ISO-8859-1?Q?Hj=F8nnev=E5g?= Cc: linux-omap@vger.kernel.org, Dima Zavin Hi, On Fri, 2011-08-05 at 00:17 -0700, Arve Hj=C3=B8nnev=C3=A5g wrote: > 2011/8/5 Tomi Valkeinen : > > On Thu, 2011-08-04 at 18:15 -0700, Arve Hj=C3=B8nnev=C3=A5g wrote: > >> 2011/8/4 Tomi Valkeinen : > >> > Hi, > >> > > >> > On Wed, 2011-06-29 at 20:44 -0700, Arve Hj=C3=B8nnev=C3=A5g wrot= e: > >> >> Change-Id: I18168c887e1384c07dc033a1ffc57abdacb26073 > >> >> Signed-off-by: Arve Hj=C3=B8nnev=C3=A5g > >> >> --- > >> >> drivers/video/omap2/dss/dsi.c | 7 ++++++- > >> >> 1 files changed, 6 insertions(+), 1 deletions(-) > >> > > >> > This feels somehow partial... Why do you want to read generic pa= ckets if > >> > there are no functions to send generic packets? > >> > > >> > >> The chip responds with a generic packet when reading from some > >> registers. This is a simple fix while adding support for sending > >> generic packets would probably require an api change. > > > > What command do you use to read the register? DCS? If so, sounds ra= ther > > strange HW implementation. > > >=20 > This change modifies dsi_vc_dcs_read to accept a generic response Ok, so you do send a DCS read command, and you get a generic response. > packet. If you want a separate generic read command that would also > work, but the it would make it a little harder to write the driver > since you then would need to know what type of response the chip > sends. Well, you do know what type of response the chip sends. According to MIPI DSI spec, a DCS read is answered with DCS short/long response, and a generic read is answered with generic short/long response. If your HW doesn't work like that, it's against the spec. If a broken chip like that was widely used, I guess we would have to add a hack for that, but until such day I want to keep the driver working as the spec says. Tomi -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html