From patchwork Fri Jun 10 10:55:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?UmV4LUJDIENoZW4gKOmZs+afj+i+sCk=?= X-Patchwork-Id: 12877448 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 BABBACCA47F for ; Fri, 10 Jun 2022 10:58:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349298AbiFJK6P (ORCPT ); Fri, 10 Jun 2022 06:58:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345119AbiFJK5s (ORCPT ); Fri, 10 Jun 2022 06:57:48 -0400 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B7A622235C; Fri, 10 Jun 2022 03:55:34 -0700 (PDT) X-UUID: 35e72cc4d33540f0af616fb4004f0944-20220610 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.5,REQID:8a8a6ca0-8242-4e59-816a-21b1275ef882,OB:0,LO B:10,IP:0,URL:5,TC:0,Content:-5,EDM:0,RT:0,SF:95,FILE:0,RULE:Release_Ham,A CTION:release,TS:95 X-CID-INFO: VERSION:1.1.5,REQID:8a8a6ca0-8242-4e59-816a-21b1275ef882,OB:0,LOB: 10,IP:0,URL:5,TC:0,Content:-5,EDM:0,RT:0,SF:95,FILE:0,RULE:Spam_GS981B3D,A CTION:quarantine,TS:95 X-CID-META: VersionHash:2a19b09,CLOUDID:57d767e5-2ba2-4dc1-b6c5-11feb6c769e0,C OID:2f937ea71e69,Recheck:0,SF:28|17|19|48,TC:nil,Content:0,EDM:-3,IP:nil,U RL:1,File:nil,QS:0,BEC:nil X-UUID: 35e72cc4d33540f0af616fb4004f0944-20220610 Received: from mtkmbs10n1.mediatek.inc [(172.21.101.34)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1565819683; Fri, 10 Jun 2022 18:55:25 +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; Fri, 10 Jun 2022 18:55:24 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.3 via Frontend Transport; Fri, 10 Jun 2022 18:55:24 +0800 From: Bo-Chen Chen To: , , , , , , , , , CC: , , , , , , , , , , , , , Bo-Chen Chen Subject: [PATCH v11 07/10] drm/mediatek: add hpd debounce Date: Fri, 10 Jun 2022 18:55:19 +0800 Message-ID: <20220610105522.13449-8-rex-bc.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220610105522.13449-1-rex-bc.chen@mediatek.com> References: <20220610105522.13449-1-rex-bc.chen@mediatek.com> MIME-Version: 1.0 X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org From: Jitao Shi From the DP spec 1.4a chapter 3.3, upstream devices should implement HPD signal de-bouncing on an external connection. A period of 100ms should be used to detect an HPD connect event. To cover these cases, HPD de-bounce should be implemented only after HPD low has been detected for at least 100ms. Therefore, 1. If HPD is low (which means plugging out) for longer than 100ms: we need to do de-bouncing (which means we need to wait for 100ms). 2. If HPD low is for less than 100ms: we don't need to care about the de-bouncing. In this patch, we start a 100ms timer and use a need_debounce boolean to implement the feature. Two cases when HPD is high: 1. If the timer is expired (>100ms): - need_debounce is true. - When HPD high (plugging event comes), need_debounce will be true and then we need to do de-bouncing (wait for 100ms). 2. If the timer is not expired (<100ms): - need_debounce is false. - When HPD high (plugging event comes), need_debounce will be false and no need to do de-bouncing. HPD_______ __________________ | |<- 100ms -> |____________| <- 100ms -> Without HPD de-bouncing, USB-C to HDMI Adapaters will not be detected. The change has been successfully tested with the following devices: - Dell Adapter - USB-C to HDMI - Acer 1in1 HDMI dongle - Ugreen 1in1 HDMI dongle - innowatt HDMI + USB3 hub - Acer 2in1 HDMI dongle - Apple 3in1 HDMI dongle (A2119) - J5Create 3in1 HDMI dongle (JAC379) Tested-by: Rex-BC Chen Reviewed-by: Rex-BC Chen Signed-off-by: Jitao Shi Signed-off-by: Guillaume Ranquet Signed-off-by: Bo-Chen Chen --- drivers/gpu/drm/mediatek/mtk_dp.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index 7c2bb2a494dd..2413551bfe9f 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -129,6 +129,8 @@ struct mtk_dp { struct mutex dp_lock; struct drm_connector *conn; + bool need_debounce; + struct timer_list debounce_timer; }; static struct regmap_config mtk_dp_regmap_config = { @@ -1681,6 +1683,9 @@ static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev) if (event < 0) return IRQ_HANDLED; + if (mtk_dp->need_debounce && mtk_dp->train_info.cable_plugged_in) + msleep(100); + dev_info(mtk_dp->dev, "drm_helper_hpd_irq_event\n"); drm_helper_hpd_irq_event(mtk_dp->bridge.dev); @@ -1766,6 +1771,12 @@ static irqreturn_t mtk_dp_hpd_isr_handler(struct mtk_dp *mtk_dp) } train_info->cable_state_change = true; + if (!train_info->cable_plugged_in) { + mod_timer(&mtk_dp->debounce_timer, + jiffies + msecs_to_jiffies(100) - 1); + mtk_dp->need_debounce = false; + } + return IRQ_WAKE_THREAD; } @@ -2216,6 +2227,13 @@ static const struct drm_bridge_funcs mtk_dp_bridge_funcs = { .detect = mtk_dp_bdg_detect, }; +static void mtk_dp_debounce_timer(struct timer_list *t) +{ + struct mtk_dp *mtk_dp = from_timer(mtk_dp, t, debounce_timer); + + mtk_dp->need_debounce = true; +} + static int mtk_dp_probe(struct platform_device *pdev) { struct mtk_dp *mtk_dp; @@ -2295,6 +2313,9 @@ static int mtk_dp_probe(struct platform_device *pdev) drm_bridge_add(&mtk_dp->bridge); + mtk_dp->need_debounce = true; + timer_setup(&mtk_dp->debounce_timer, mtk_dp_debounce_timer, 0); + pm_runtime_enable(dev); pm_runtime_get_sync(dev); @@ -2307,6 +2328,7 @@ static int mtk_dp_remove(struct platform_device *pdev) platform_device_unregister(mtk_dp->phy_dev); mtk_dp_video_mute(mtk_dp, true); + del_timer_sync(&mtk_dp->debounce_timer); pm_runtime_disable(&pdev->dev);