From patchwork Sat Jul 29 20:43:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Baryshkov X-Patchwork-Id: 13333227 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 EDF39C41513 for ; Sat, 29 Jul 2023 20:43:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229568AbjG2UnO (ORCPT ); Sat, 29 Jul 2023 16:43:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229547AbjG2UnN (ORCPT ); Sat, 29 Jul 2023 16:43:13 -0400 Received: from mail-lf1-x12b.google.com (mail-lf1-x12b.google.com [IPv6:2a00:1450:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67632129 for ; Sat, 29 Jul 2023 13:43:11 -0700 (PDT) Received: by mail-lf1-x12b.google.com with SMTP id 2adb3069b0e04-4fe1a35a135so4637881e87.1 for ; Sat, 29 Jul 2023 13:43:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1690663389; x=1691268189; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=jDXmcqoxmADeVwH/tIKhJpnlMjbMtWv3iZzEIatWUZw=; b=HkMSKw6/PCLIipl8FiTm78l3ypb7hctz3Xfn/gOmLxJ/fYuTukfw1ejsn/q0zK9UsT SH116GxJEl/Q3dsvRSUzTfiDC/m3WqJJ3uXeM43aHy2kibo+wXbS5rzAV+OUEeggBXAb NoLaD9pQT/8b09UhE7o3an3Z2kFRUna54v5EhMcUJHgw7kNzD2v0NRvJyaP1r9BjbDvx nhd1YOfm7+SDwoa6D+RNDhefq9NwGHjXs0YcGumW1kjNN+gUq4CRXEZ5+jshOemMmtp8 9+yr+9hi3uY1prDiJaMnNe6FofthZLm+kJmx4+Wkcd68hdrIwL/92SRyPp2qmqzMuwu8 UxZg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690663389; x=1691268189; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=jDXmcqoxmADeVwH/tIKhJpnlMjbMtWv3iZzEIatWUZw=; b=HrggNOOzWulFrMcRDU59jHkBxvmIKv5og7G7VB1CywHgb+pYhDlVDcF8jkOb1t/N59 2GmSxUrqRUMIGDAXA3lMKcA4F5PrtPo+vz6NKABDf+YXdKgBTUoiNzDGEBrJBjeZzQOV iY7UQ+hQ+4aUSTU1/ce2/3/DVgZkNgU/tP1rB/ZmQhqrsQ+1vNOWq9iL31NI4+K0/ICi DzFOcIURBUDZchccfzGJIoR0yZz07AxL5ARE7mrrZfdGz5XHFDr8jA3Pj2QqqI5JQGMR wEiOq9DJhiyvMtE2h+yNpoNvYOHiBw0MNymOKhAOGX1dAqYQNPy/WO0GG1b0l6SRPiAk 8IPw== X-Gm-Message-State: ABy/qLZVOu9seqQBgytRiRHrwJB6sYWLNBtAKqm+xuASp5+/hjQHIJYI 6uduIC4yZxHBPTGkqvI9RKtiJw== X-Google-Smtp-Source: APBJJlEG7RXwuvRy6gHyJpQWKQOXsq5ExDxgmuPzEO/9ZMBjN/9HwLfl4RJQVaeeQPngeNEsL7Yydg== X-Received: by 2002:a2e:b0d1:0:b0:2b9:4ac9:6071 with SMTP id g17-20020a2eb0d1000000b002b94ac96071mr3844531ljl.10.1690663389536; Sat, 29 Jul 2023 13:43:09 -0700 (PDT) Received: from umbar.unikie.fi ([192.130.178.91]) by smtp.gmail.com with ESMTPSA id v20-20020a2e9614000000b002b9af8422a8sm1705177ljh.130.2023.07.29.13.43.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Jul 2023 13:43:08 -0700 (PDT) From: Dmitry Baryshkov To: David Airlie , Daniel Vetter , Andy Gross , Bjorn Andersson , Konrad Dybcio , Vinod Koul , Kishon Vijay Abraham I , Heikki Krogerus , Greg Kroah-Hartman , Neil Armstrong Cc: dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org, linux-usb@vger.kernel.org Subject: [PATCH 0/3] drm/display: simplify support for transparent DRM bridges Date: Sat, 29 Jul 2023 23:43:04 +0300 Message-Id: <20230729204307.268587-1-dmitry.baryshkov@linaro.org> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Supporting DP/USB-C can result in a chain of several transparent bridges (PHY, redrivers, mux, etc). This results in drivers having similar boilerplate code for such bridges. Next, these drivers are susceptible to -EPROBE_DEFER loops: the next bridge can either be probed from the bridge->attach callback, when it is too late to return -EPROBE_DEFER, or from the probe() callback, when the next bridge might not yet be available, because it depends on the resources provided by the probing device. Last, but not least, this results in the the internal knowledge of DRM subsystem slowly diffusing into other subsystems, like PHY or USB/TYPEC. To solve all these issues, define a separate DRM helper, which creates separate aux device just for the bridge. During probe such aux device doesn't result in the EPROBE_DEFER loops. Instead it allows the device drivers to probe properly, according to the actual resource dependencies. The bridge auxdevs are then probed when the next bridge becomes available, sparing drivers from drm_bridge_attach() returning -EPROBE_DEFER. Proposed merge strategy: immutable branch with the drm commit, which is then merged into PHY and USB subsystems together with the corresponding patch. Dmitry Baryshkov (3): drm/display: add transparent bridge helper phy: qcom: qmp-combo: switch to DRM_SIMPLE_BRIDGE usb: typec: nb7vpq904m: switch to DRM_SIMPLE_BRIDGE drivers/gpu/drm/display/Kconfig | 9 ++ drivers/gpu/drm/display/Makefile | 2 + drivers/gpu/drm/display/drm_simple_bridge.c | 120 ++++++++++++++++++++ drivers/phy/qualcomm/Kconfig | 3 +- drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 44 +------ drivers/usb/typec/mux/Kconfig | 3 +- drivers/usb/typec/mux/nb7vpq904m.c | 44 +------ include/drm/display/drm_simple_bridge.h | 19 ++++ 8 files changed, 156 insertions(+), 88 deletions(-) create mode 100644 drivers/gpu/drm/display/drm_simple_bridge.c create mode 100644 include/drm/display/drm_simple_bridge.h