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 3B475CCA47E for ; Tue, 7 Jun 2022 06:44:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237196AbiFGGom (ORCPT ); Tue, 7 Jun 2022 02:44:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232554AbiFGGok (ORCPT ); Tue, 7 Jun 2022 02:44:40 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 560B7B0A76; Mon, 6 Jun 2022 23:44:38 -0700 (PDT) X-UUID: f2ff2b99b3a6428b81381a0435a5737a-20220607 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.5,REQID:bd6e63f1-6500-4bea-bd3e-52a63a9384c9,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:2a19b09,CLOUDID:bde48d21-199a-43f9-af93-057fe480bdd5,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:0,File:nil ,QS:0,BEC:nil X-UUID: f2ff2b99b3a6428b81381a0435a5737a-20220607 Received: from mtkexhb01.mediatek.inc [(172.21.101.102)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 528559842; Tue, 07 Jun 2022 14:44:33 +0800 Received: from mtkmbs11n1.mediatek.inc (172.21.101.185) by mtkmbs11n1.mediatek.inc (172.21.101.185) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.792.3; Tue, 7 Jun 2022 14:44:32 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.3 via Frontend Transport; Tue, 7 Jun 2022 14:44:32 +0800 Message-ID: Subject: Re: [PATCH v10 18/21] drm/mediatek: Add mt8195 Embedded DisplayPort driver From: CK Hu To: Rex-BC Chen , Guillaume Ranquet , Chun-Kuang Hu , "Philipp Zabel" , David Airlie , "Daniel Vetter" , Rob Herring , "Krzysztof Kozlowski" , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Matthias Brugger , Chunfeng Yun , "Kishon Vijay Abraham I" , Vinod Koul , "Helge Deller" , Jitao shi CC: Markus Schneider-Pargmann , , , , , , , Date: Tue, 7 Jun 2022 14:44:32 +0800 In-Reply-To: <20220523104758.29531-19-granquet@baylibre.com> References: <20220523104758.29531-1-granquet@baylibre.com> <20220523104758.29531-19-granquet@baylibre.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: devicetree@vger.kernel.org Hi, Rex: On Mon, 2022-05-23 at 12:47 +0200, Guillaume Ranquet wrote: > From: Markus Schneider-Pargmann > > This patch adds a 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 > Jason-JH.Lin . > > Signed-off-by: Markus Schneider-Pargmann > Signed-off-by: Guillaume Ranquet > --- [snip] > + > +static int mtk_dp_train_handler(struct mtk_dp *mtk_dp) > +{ > + bool training_done = false; > + short max_retry = 50; > + int ret = 0; > + > + do { > + switch (mtk_dp->train_state) { > + case MTK_DP_TRAIN_STATE_STARTUP: mtk_dp->train_state is initialized as MTK_DP_TRAIN_STATE_STARTUP even though HPD ISR does not exist. Does this mean HPD ISR is redundant? If HPD ISR is not redundant, create a new state MTK_DP_TRAIN_STATE_NONE for init state. > + mtk_dp_state_handler(mtk_dp); > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_CHECKCAP; > + break; > + > + case MTK_DP_TRAIN_STATE_CHECKCAP: > + if (mtk_dp_parse_capabilities(mtk_dp)) { > + mtk_dp->train_info.check_cap_count = 0; > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_CHECKEDID; > + } else { > + mtk_dp->train_info.check_cap_count++; > + > + if (mtk_dp->train_info.check_cap_count > > > + MTK_DP_CHECK_SINK_CAP_TIMEOUT_COUNT > ) { > + mtk_dp- > >train_info.check_cap_count = 0; > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_DPIDLE; > + ret = -ETIMEDOUT; > + } > + } > + break; > + > + case MTK_DP_TRAIN_STATE_CHECKEDID: > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_TRAINING_PRE; MTK_DP_TRAIN_STATE_CHECKEDID is a redundant state, drop it. > + break; > + > + case MTK_DP_TRAIN_STATE_TRAINING_PRE: > + mtk_dp_state_handler(mtk_dp); > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_TRAINING; > + break; > + > + case MTK_DP_TRAIN_STATE_TRAINING: > + ret = mtk_dp_train_start(mtk_dp); > + if (ret == 0) { > + mtk_dp_video_mute(mtk_dp, true); > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_NORMAL; > + mtk_dp_fec_enable(mtk_dp, mtk_dp- > >has_fec); > + } else if (ret != -EAGAIN) { > + mtk_dp->train_state = > MTK_DP_TRAIN_STATE_DPIDLE; > + } > + break; > + case MTK_DP_TRAIN_STATE_NORMAL: > + mtk_dp_state_handler(mtk_dp); > + training_done = true; > + break; > + case MTK_DP_TRAIN_STATE_DPIDLE: When would this case happen? Regards, CK > + break; > + default: > + break; > + } > + > + if (ret) { > + if (ret == -EAGAIN) > + continue; > + /* > + * If we get any other error number, it doesn't > + * make any sense to keep iterating. > + */ > + break; > + } > + } while (!training_done || --max_retry); > + > + return ret; > +}