From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C6D4C49ED7 for ; Mon, 16 Sep 2019 10:36:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DA6221848 for ; Mon, 16 Sep 2019 10:36:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=onstation.org header.i=@onstation.org header.b="mYdC2Jos" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731104AbfIPKgR (ORCPT ); Mon, 16 Sep 2019 06:36:17 -0400 Received: from onstation.org ([52.200.56.107]:40790 "EHLO onstation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728134AbfIPKgR (ORCPT ); Mon, 16 Sep 2019 06:36:17 -0400 Received: from localhost (c-98-239-145-235.hsd1.wv.comcast.net [98.239.145.235]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: masneyb) by onstation.org (Postfix) with ESMTPSA id 35DF83E8F9; Mon, 16 Sep 2019 10:36:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=onstation.org; s=default; t=1568630176; bh=4KQmgz71YU3A68V+Z3HaVPiT+RBIQPuGE3xqAmSJ6fE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mYdC2Jostpc6JnzwEQKwLhjI7/uhjM7Lt0RJ5HB20fuJn1eObXMqrg4rMz0NWQAha 9mZxUJPUj3+2M4JFGaGm27QPrkXQDLGJNiBeRsEplRktcZoLHydxXxBglCpX5+wd9L fPvoREGjrIlTtEyAFeXHDspo9m5N2e4aerYO4rDQ= Date: Mon, 16 Sep 2019 06:36:14 -0400 From: Brian Masney To: Andrzej Hajda Cc: bjorn.andersson@linaro.org, robh+dt@kernel.org, agross@kernel.org, narmstrong@baylibre.com, robdclark@gmail.com, sean@poorly.run, airlied@linux.ie, daniel@ffwll.ch, mark.rutland@arm.com, Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se, jernej.skrabec@siol.net, linus.walleij@linaro.org, enric.balletbo@collabora.com, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, freedreno@lists.freedesktop.org Subject: Re: [PATCH 05/11] drm/bridge: analogix-anx78xx: correct value of TX_P0 Message-ID: <20190916103614.GA1644@onstation.org> References: <20190815004854.19860-1-masneyb@onstation.org> <20190815004854.19860-6-masneyb@onstation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 16, 2019 at 12:02:09PM +0200, Andrzej Hajda wrote: > On 15.08.2019 02:48, Brian Masney wrote: > > When attempting to configure this driver on a Nexus 5 phone (msm8974), > > setting up the dummy i2c bus for TX_P0 would fail due to an -EBUSY > > error. The downstream MSM kernel sources [1] shows that the proper value > > for TX_P0 is 0x78, not 0x70, so correct the value to allow device > > probing to succeed. > > > > [1] https://github.com/AICP/kernel_lge_hammerhead/blob/n7.1/drivers/video/slimport/slimport_tx_reg.h > > > > Signed-off-by: Brian Masney > > --- > > drivers/gpu/drm/bridge/analogix-anx78xx.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/bridge/analogix-anx78xx.h b/drivers/gpu/drm/bridge/analogix-anx78xx.h > > index 25e063bcecbc..bc511fc605c9 100644 > > --- a/drivers/gpu/drm/bridge/analogix-anx78xx.h > > +++ b/drivers/gpu/drm/bridge/analogix-anx78xx.h > > @@ -6,7 +6,7 @@ > > #ifndef __ANX78xx_H > > #define __ANX78xx_H > > > > -#define TX_P0 0x70 > > +#define TX_P0 0x78 > > > This bothers me little. There are no upstream users, grepping android > sources suggests that both values can be used [1][2]  (grep for "#define > TX_P0"), moreover there is code suggesting both values can be valid [3]. > > Could you verify datasheet which i2c slave addresses are valid for this > chip, if both I guess this patch should be reworked. > > > [1]: > https://android.googlesource.com/kernel/msm/+/android-msm-flo-3.4-jb-mr2/drivers/misc/slimport_anx7808/slimport_tx_reg.h > > [2]: > https://github.com/AndroidGX/SimpleGX-MM-6.0_H815_20d/blob/master/drivers/video/slimport/anx7812/slimport7812_tx_reg.h > > [3]: > https://github.com/commaai/android_kernel_leeco_msm8996/blob/master/drivers/video/msm/mdss/dp/slimport_custom_declare.h#L73 This address is 0x78 on my Nexus 5. Given [3] above it looks like we need to support both addresses. What do you think about moving these addresses into device tree? The downstream and upstream kernel sources divide these addresses by two to get the i2c address. Here's the code in upstream: https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/bridge/analogix-anx78xx.c#L1353 https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/bridge/analogix-anx78xx.c#L41 I'm not sure why the actual i2c address isn't used in this code. Brian