From patchwork Thu Sep 1 04:41:48 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: 12961757 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 81E09C64991 for ; Thu, 1 Sep 2022 04:42:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232365AbiIAEmJ (ORCPT ); Thu, 1 Sep 2022 00:42:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232176AbiIAEmF (ORCPT ); Thu, 1 Sep 2022 00:42:05 -0400 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABEEBE1AA5; Wed, 31 Aug 2022 21:42:02 -0700 (PDT) X-UUID: a0a740fcb3f849f6833c07684c6a1073-20220901 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=KUl585Ew6V3M6jylysyr0wYhICqdfWGeJ4BWd0htx6k=; b=GI9zVnWRu1HCAxa8AHBgK2zSf6qWerF4WzToep8rSRLWkBpNg9P1mbMlE37egQh3N7f5pUT4miX7/Tlh/PpAwIlKg0Z5PbiW+gcOrmEivk2LoROkIrCHcIkJTy5V6gqCFxm533FTBrjAy65FdE2o/tRr7GCVm+45QLHNnsK2WVw=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.10,REQID:17c21edc-953e-472c-86e9-517504ecc20b,OB:0,L OB:0,IP:0,URL:0,TC:0,Content:-25,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Releas e_Ham,ACTION:release,TS:-25 X-CID-META: VersionHash:84eae18,CLOUDID:c918c520-1c20-48a5-82a0-25f9c331906d,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:11|1,File: nil,Bulk:nil,QS:nil,BEC:nil,COL:0 X-UUID: a0a740fcb3f849f6833c07684c6a1073-20220901 Received: from mtkmbs11n2.mediatek.inc [(172.21.101.187)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1572896759; Thu, 01 Sep 2022 12:41:54 +0800 Received: from mtkmbs11n1.mediatek.inc (172.21.101.186) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.792.15; Thu, 1 Sep 2022 12:41:53 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.15 via Frontend Transport; Thu, 1 Sep 2022 12:41:53 +0800 From: Bo-Chen Chen To: , , , , , , , , , CC: , , , , , , , , , , , , , , Bo-Chen Chen Subject: [PATCH v17 09/10] drm/mediatek: dp: Add hpd debounce Date: Thu, 1 Sep 2022 12:41:48 +0800 Message-ID: <20220901044149.16782-10-rex-bc.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220901044149.16782-1-rex-bc.chen@mediatek.com> References: <20220901044149.16782-1-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 Reviewed-by: CK Hu --- drivers/gpu/drm/mediatek/mtk_dp.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index 11a94927c0d0..dd34dae417e5 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -87,6 +87,7 @@ struct mtk_dp_efuse_fmt { struct mtk_dp { bool enabled; + bool need_debounce; u8 max_lanes; u8 max_linkrate; u8 rx_cap[DP_RECEIVER_CAP_SIZE]; @@ -109,6 +110,7 @@ struct mtk_dp { struct platform_device *phy_dev; struct phy *phy; struct regmap *regs; + struct timer_list debounce_timer; }; struct mtk_dp_data { @@ -1475,14 +1477,24 @@ static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev) unsigned long flags; u32 status; + if (mtk_dp->need_debounce && mtk_dp->train_info.cable_plugged_in) + msleep(100); + spin_lock_irqsave(&mtk_dp->irq_thread_lock, flags); status = mtk_dp->irq_thread_handle; mtk_dp->irq_thread_handle = 0; spin_unlock_irqrestore(&mtk_dp->irq_thread_lock, flags); - if (status & MTK_DP_THREAD_CABLE_STATE_CHG) + if (status & MTK_DP_THREAD_CABLE_STATE_CHG) { drm_helper_hpd_irq_event(mtk_dp->bridge.dev); + if (!mtk_dp->train_info.cable_plugged_in) { + mtk_dp->need_debounce = false; + mod_timer(&mtk_dp->debounce_timer, + jiffies + msecs_to_jiffies(100) - 1); + } + } + if (status & MTK_DP_THREAD_HPD_EVENT) dev_dbg(mtk_dp->dev, "Receive IRQ from sink devices\n"); @@ -1996,6 +2008,13 @@ 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; @@ -2069,6 +2088,9 @@ 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); @@ -2081,6 +2103,7 @@ static int mtk_dp_remove(struct platform_device *pdev) pm_runtime_put(&pdev->dev); pm_runtime_disable(&pdev->dev); + del_timer_sync(&mtk_dp->debounce_timer); drm_bridge_remove(&mtk_dp->bridge); platform_device_unregister(mtk_dp->phy_dev);