From patchwork Fri Aug 5 10:14:56 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: 12937153 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 4A2E6C00140 for ; Fri, 5 Aug 2022 10:15:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240611AbiHEKPP (ORCPT ); Fri, 5 Aug 2022 06:15:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231225AbiHEKPN (ORCPT ); Fri, 5 Aug 2022 06:15:13 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0F936D550; Fri, 5 Aug 2022 03:15:09 -0700 (PDT) X-UUID: ef2f6b40a6394a8eab4fab23b6e088fb-20220805 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From; bh=nfIRO5FTp4YZRztdUpgyKztSf349oawEmxk993clnQE=; b=KcnK/6V4j0Reh2c//mQDPAyncKYfCOGcpDscf07yk33emRgyVYePTSR7SdBTcxPHjsWrLjmDgVmU/ivOTx122sSJ7ynChgWC4vjZ0ZRlJL+BaorS0CurSzeAGQHbv9WlydXCf1hWs5nlxw4rBxDPY4X2xgvJJzOl9ZhGLHVsvsI=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.8,REQID:5d7e92db-50b4-4e01-a45d-c1bb034fdd27,OB:0,LO B:0,IP:0,URL:5,TC:0,Content:-5,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACT ION:release,TS:0 X-CID-META: VersionHash:0f94e32,CLOUDID:fe10e19b-da39-4e3b-a854-56c7d2111b46,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:1,File:nil ,QS:nil,BEC:nil,COL:0 X-UUID: ef2f6b40a6394a8eab4fab23b6e088fb-20220805 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 2061949579; Fri, 05 Aug 2022 18:15:01 +0800 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.15; Fri, 5 Aug 2022 18:15:00 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 5 Aug 2022 18:15:00 +0800 From: Bo-Chen Chen To: , , , , , , , , , CC: , , , , , , , , , , , , , , Bo-Chen Chen Subject: [PATCH v16 5/8] drm/mediatek: add hpd debounce Date: Fri, 5 Aug 2022 18:14:56 +0800 Message-ID: <20220805101459.3386-6-rex-bc.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220805101459.3386-1-rex-bc.chen@mediatek.com> References: <20220805101459.3386-1-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 Reviewed-by: AngeloGioacchino Del Regno --- drivers/gpu/drm/mediatek/mtk_dp.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index 00971ea2fadf..487f3ed0c19f 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -95,6 +95,8 @@ struct mtk_dp { bool enabled; struct drm_connector *conn; + bool need_debounce; + struct timer_list debounce_timer; }; struct mtk_dp_data { @@ -1479,6 +1481,9 @@ static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev) dev_dbg(mtk_dp->dev, "MTK_DP_HPD_INTERRUPT\n"); + if (mtk_dp->need_debounce && mtk_dp->train_info.cable_plugged_in) + msleep(100); + drm_helper_hpd_irq_event(mtk_dp->bridge.dev); mtk_dp->train_info.hpd_inerrupt = false; mtk_dp_hpd_sink_event(mtk_dp); @@ -1525,6 +1530,10 @@ static irqreturn_t mtk_dp_hpd_event(int hpd, void *dev) mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE, DP_PWR_STATE_BANDGAP_TPLL, DP_PWR_STATE_MASK); + + mod_timer(&mtk_dp->debounce_timer, + jiffies + msecs_to_jiffies(100) - 1); + mtk_dp->need_debounce = false; } else { mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE, DP_PWR_STATE_BANDGAP_TPLL_LANE, @@ -1945,6 +1954,13 @@ 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; @@ -2020,6 +2036,9 @@ 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); @@ -2032,6 +2051,7 @@ 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);