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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7FE2EC43334 for ; Tue, 12 Jul 2022 06:57:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231730AbiGLG52 (ORCPT ); Tue, 12 Jul 2022 02:57:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229529AbiGLG5Y (ORCPT ); Tue, 12 Jul 2022 02:57:24 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0CFC951CC; Mon, 11 Jul 2022 23:57:22 -0700 (PDT) X-UUID: 098aa1e34f294927bc99f0d4833748ad-20220712 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.8,REQID:cfc356d1-53a1-4a27-8af5-3e9cd555aa1f,OB:0,LO B:0,IP:0,URL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACTI ON:release,TS:0 X-CID-META: VersionHash:0f94e32,CLOUDID:7df7bb32-b9e4-42b8-b28a-6364427c76bb,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:0,File:nil ,QS:nil,BEC:nil,COL:0 X-UUID: 098aa1e34f294927bc99f0d4833748ad-20220712 Received: from mtkmbs10n2.mediatek.inc [(172.21.101.183)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 558935923; Tue, 12 Jul 2022 14:57:17 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs11n2.mediatek.inc (172.21.101.187) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.3; Tue, 12 Jul 2022 14:57:15 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Tue, 12 Jul 2022 14:57:15 +0800 Message-ID: Subject: Re: [PATCH v13 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver From: Rex-BC Chen To: CK Hu , "chunkuang.hu@kernel.org" , "p.zabel@pengutronix.de" , "daniel@ffwll.ch" , "robh+dt@kernel.org" , "krzysztof.kozlowski+dt@linaro.org" , "mripard@kernel.org" , "tzimmermann@suse.de" , "matthias.bgg@gmail.com" , "deller@gmx.de" , "airlied@linux.ie" CC: "msp@baylibre.com" , "granquet@baylibre.com" , "Jitao Shi =?UTF-8?Q?=28=E7=9F=B3=E8=AE=B0=E6=B6=9B=29?=" , "wenst@chromium.org" , "angelogioacchino.delregno@collabora.com" , "LiangXu Xu =?UTF-8?Q?=28=E5=BE=90=E4=BA=AE=29?=" , "dri-devel@lists.freedesktop.org" , "linux-mediatek@lists.infradead.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-fbdev@vger.kernel.org" , Project_Global_Chrome_Upstream_Group Date: Tue, 12 Jul 2022 14:57:15 +0800 In-Reply-To: <6b4a4be9b5c93b1931cdbd5b009eac3bfa9badbe.camel@mediatek.com> References: <20220701062808.18596-1-rex-bc.chen@mediatek.com> <20220701062808.18596-6-rex-bc.chen@mediatek.com> <6b4a4be9b5c93b1931cdbd5b009eac3bfa9badbe.camel@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2022-07-07 at 13:14 +0800, CK Hu wrote: > Hi, Bo-Chen: > > On Fri, 2022-07-01 at 14:28 +0800, Bo-Chen Chen wrote: > > From: Markus Schneider-Pargmann > > > > This patch adds a embedded displayport driver for the MediaTek > > mt8195 > > SoC. > > > > It supports the MT8195, the embedded DisplayPort units. It offers > > DisplayPort 1.4 with up to 4 lanes. > > > > The driver creates a child device for the phy. The child device > > will > > never exist without the parent being active. As they are sharing a > > register range, the parent passes a regmap pointer to the child so > > that > > both can work with the same register range. The phy driver sets > > device > > data that is read by the parent to get the phy device that can be > > used > > to control the phy properties. > > > > This driver is based on an initial version by > > Jitao shi > > > > Signed-off-by: Markus Schneider-Pargmann > > Signed-off-by: Guillaume Ranquet > > Signed-off-by: Bo-Chen Chen > > --- > > [snip] > > > + > > +static ssize_t mtk_dp_hpd_sink_event(struct mtk_dp *mtk_dp) > > The caller never use the return value, so let this function to void. > > > +{ > > + ssize_t ret; > > + u8 sink_count; > > + u8 link_status[DP_LINK_STATUS_SIZE] = {}; > > + u32 sink_count_reg = DP_SINK_COUNT_ESI; > > + u32 link_status_reg = DP_LANE0_1_STATUS; > > + > > + ret = drm_dp_dpcd_readb(&mtk_dp->aux, sink_count_reg, > > &sink_count); > > You read sink_count but never use it, so this read is redundant. > Remove > it. > Hello CK, this is a pre-request for the following codes, so I think we need to keep this. If we failed to read sink_count, we don't need to do the driver under this. > > + if (ret < 1) { > > + drm_err(mtk_dp->drm_dev, "Read sink count failed\n"); > > + return ret == 0 ? -EIO : ret; > > + } > > + > > + ret = drm_dp_dpcd_read(&mtk_dp->aux, link_status_reg, > > link_status, > > + sizeof(link_status)); > > + if (!ret) { > > + drm_err(mtk_dp->drm_dev, "Read link status failed\n"); > > + return ret; > > + } > > + > > + drm_dp_channel_eq_ok(link_status, mtk_dp- > > > train_info.lane_count); > > This function just return true or false, and you does not process the > return value, so this is redundant. Remove it. > I will handle this in next version. BRs, Bo-Chen > Regard, > CK > > > + > > + if (link_status[1] & DP_REMOTE_CONTROL_COMMAND_PENDING) > > + drm_dp_dpcd_writeb(&mtk_dp->aux, > > DP_DEVICE_SERVICE_IRQ_VECTOR, > > + DP_REMOTE_CONTROL_COMMAND_PENDING); > > + > > + return 0; > > +} > >