From patchwork Wed Jan 10 14:12:26 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Walleij X-Patchwork-Id: 10155219 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4D8ED60231 for ; Wed, 10 Jan 2018 14:12:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3EA352845C for ; Wed, 10 Jan 2018 14:12:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 336E52858E; Wed, 10 Jan 2018 14:12:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id CA1D62845C for ; Wed, 10 Jan 2018 14:12:42 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B34C56E2D8; Wed, 10 Jan 2018 14:12:41 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-lf0-x244.google.com (mail-lf0-x244.google.com [IPv6:2a00:1450:4010:c07::244]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9DB2D6E2D8 for ; Wed, 10 Jan 2018 14:12:40 +0000 (UTC) Received: by mail-lf0-x244.google.com with SMTP id m8so13930057lfc.6 for ; Wed, 10 Jan 2018 06:12:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=/gBFTrI0KIXSs8pCWtsRDDOFrm0TSyo4lpBgEk5HEB8=; b=d50GunxG0Uc7yi4AAOOzReTtyfF6EM2H7w3PRri/y2Fyr2L/pt3oMjEvCVc2hQ7yaI i/F2fItEPt19fYjGan/jmz056bY89N4QPEmKtEZm/MPu5Luxb1H/WIUeFjA2chlfWPOj GovQxm12+iYzmXNiCISpnhgLJlclD8FCyjAyY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=/gBFTrI0KIXSs8pCWtsRDDOFrm0TSyo4lpBgEk5HEB8=; b=P8cNN2ZMT3hVD2eKNt9OY4LSMbTmO5PN1l8JLuuUeNduhoxkvmN3KQESTyQ5pkxyEA y+gN/e3seeCp30MB+sPt6gQCGxX/TTxJOrx4aAeP9qphdcpVzpDTQdsHvRYZ7IzEpC1s +BLlOWp3nNeWoxRFZWgACqi8v8vTM62Z/XL1obdYJkMB5zvZnMbiazHNK9ZhRnDhl6CE cEDCD8quL80R+IkzfbxccMsyAaOaXSKqz9FlIZzg7/KRuid8xtAlHW1KBkrDJ351RUHx vVPQFChxvyMzl5Z7vrYjKNNNdY+LFzEr8C/cfVYOMvLNwD8MhSIWYviWcJIq8tBwC1EJ fzRg== X-Gm-Message-State: AKwxytcjp7RuQpWHuDUWNRs8gGBxF5chjCYmnIGyGU+GqFaXJ3Jgni2g 1xLODDQL2hiBfc16jKngzY6lXA== X-Google-Smtp-Source: ACJfBotq1q6c5nrgUJrVwk6TCelvMChofRlBUhXp4aVELEnW5qn13L0q6oHmbfR+RCLXzbO4sO2jnQ== X-Received: by 10.25.212.83 with SMTP id l80mr8683204lfg.83.1515593558862; Wed, 10 Jan 2018 06:12:38 -0800 (PST) Received: from genomnajs.ideon.se ([85.235.10.227]) by smtp.gmail.com with ESMTPSA id u72sm1019258lfi.64.2018.01.10.06.12.37 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 10 Jan 2018 06:12:38 -0800 (PST) From: Linus Walleij To: Archit Taneja , Andrzej Hajda , Laurent Pinchart Subject: [PATCH 4/4 v6] drm/pl111: Support handling bridge timings Date: Wed, 10 Jan 2018 15:12:26 +0100 Message-Id: <20180110141226.27826-4-linus.walleij@linaro.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180110141226.27826-1-linus.walleij@linaro.org> References: <20180110141226.27826-1-linus.walleij@linaro.org> Cc: linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP If the bridge has a too strict setup time for the incoming signals, we may not be fast enough and then we need to compensate by outputting the signal on the inverse clock edge so it is for sure stable when the bridge samples it. Since bridges in difference to panels does not expose their connectors, make the connector optional in the display setup code. Acked-by: Laurent Pinchart Signed-off-by: Linus Walleij Reviewed-by: Eric Anholt --- ChangeLog v5->v6: - Collect Laurent's ACK. ChangeLog v4->v5: - Use the new bridge timings setup method. --- drivers/gpu/drm/pl111/Kconfig | 1 + drivers/gpu/drm/pl111/pl111_display.c | 35 +++++++++++++++++++++++++++++++---- drivers/gpu/drm/pl111/pl111_drv.c | 20 +++++++++++--------- 3 files changed, 43 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/pl111/Kconfig b/drivers/gpu/drm/pl111/Kconfig index e5e2abd66491..82cb3e60ddc8 100644 --- a/drivers/gpu/drm/pl111/Kconfig +++ b/drivers/gpu/drm/pl111/Kconfig @@ -8,6 +8,7 @@ config DRM_PL111 select DRM_GEM_CMA_HELPER select DRM_BRIDGE select DRM_PANEL_BRIDGE + select DRM_DUMB_VGA_DAC select VT_HW_CONSOLE_BINDING if FRAMEBUFFER_CONSOLE help Choose this option for DRM support for the PL111 CLCD controller. diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c index 06c4bf756b69..7fe4040aea46 100644 --- a/drivers/gpu/drm/pl111/pl111_display.c +++ b/drivers/gpu/drm/pl111/pl111_display.c @@ -94,6 +94,7 @@ static void pl111_display_enable(struct drm_simple_display_pipe *pipe, const struct drm_display_mode *mode = &cstate->mode; struct drm_framebuffer *fb = plane->state->fb; struct drm_connector *connector = priv->connector; + struct drm_bridge *bridge = priv->bridge; u32 cntl; u32 ppl, hsw, hfp, hbp; u32 lpp, vsw, vfp, vbp; @@ -143,11 +144,37 @@ static void pl111_display_enable(struct drm_simple_display_pipe *pipe, if (mode->flags & DRM_MODE_FLAG_NVSYNC) tim2 |= TIM2_IVS; - if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW) - tim2 |= TIM2_IOE; + if (connector) { + if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW) + tim2 |= TIM2_IOE; - if (connector->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE) - tim2 |= TIM2_IPC; + if (connector->display_info.bus_flags & + DRM_BUS_FLAG_PIXDATA_NEGEDGE) + tim2 |= TIM2_IPC; + } + + if (bridge) { + const struct drm_bridge_timings *btimings = bridge->timings; + + /* + * Here is when things get really fun. Sometimes the bridge + * timings are such that the signal out from PL11x is not + * stable before the receiving bridge (such as a dumb VGA DAC + * or similar) samples it. If that happens, we compensate by + * the only method we have: output the data on the opposite + * edge of the clock so it is for sure stable when it gets + * sampled. + * + * The PL111 manual does not contain proper timining diagrams + * or data for these details, but we know from experiments + * that the setup time is more than 3000 picoseconds (3 ns). + * If we have a bridge that requires the signal to be stable + * earlier than 3000 ps before the clock pulse, we have to + * output the data on the opposite edge to avoid flicker. + */ + if (btimings && btimings->setup_time_ps >= 3000) + tim2 ^= TIM2_IPC; + } tim2 |= cpl << 16; writel(tim2, priv->regs + CLCD_TIM2); diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c index 201d57d5cb54..101a9c7db6ff 100644 --- a/drivers/gpu/drm/pl111/pl111_drv.c +++ b/drivers/gpu/drm/pl111/pl111_drv.c @@ -107,11 +107,17 @@ static int pl111_modeset_init(struct drm_device *dev) ret = PTR_ERR(bridge); goto out_config; } - /* - * TODO: when we are using a different bridge than a panel - * (such as a dumb VGA connector) we need to devise a different - * method to get the connector out of the bridge. - */ + } else if (bridge) { + dev_info(dev->dev, "Using non-panel bridge\n"); + } else { + dev_err(dev->dev, "No bridge, exiting\n"); + return -ENODEV; + } + + priv->bridge = bridge; + if (panel) { + priv->panel = panel; + priv->connector = panel->connector; } ret = pl111_display_init(dev); @@ -125,10 +131,6 @@ static int pl111_modeset_init(struct drm_device *dev) if (ret) return ret; - priv->bridge = bridge; - priv->panel = panel; - priv->connector = panel->connector; - ret = drm_vblank_init(dev, 1); if (ret != 0) { dev_err(dev->dev, "Failed to init vblank\n");