From patchwork Thu Apr 23 16:25:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 11506033 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C889C159A for ; Thu, 23 Apr 2020 16:26:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACA1620857 for ; Thu, 23 Apr 2020 16:26:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="dIQkxfsL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729674AbgDWQ0g (ORCPT ); Thu, 23 Apr 2020 12:26:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33908 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1729675AbgDWQ0Q (ORCPT ); Thu, 23 Apr 2020 12:26:16 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BA7FC09B043 for ; Thu, 23 Apr 2020 09:26:15 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id p8so3136672pgi.5 for ; Thu, 23 Apr 2020 09:26:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=vgEC77DVt2b0ue/xtejv20IChECVhC3qlcIR/cy95lM=; b=dIQkxfsLIvlw5/ZBCbkq5EOQs4v/Xx8/bczbStS1CbtDaXlX1du/8xNyoi9zxrO8wy xCZG+UFD0Qo2YWWLTn4BFjDZJ7dPoW7Apt0UdwirEIPuGqnhGNnFwDHEDZtGP/yUtbkH 0mGvdMGciBK/YMuN75ZWyDjPFnnmDjvcN31zE= 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:mime-version:content-transfer-encoding; bh=vgEC77DVt2b0ue/xtejv20IChECVhC3qlcIR/cy95lM=; b=gCKWmC/nEZKB87sJlwoA1s3IpNYirTqyQH1XMEWcUDbImRQ722zoTPYw3ZAREaZIUh tRLzc3ylQfKEyurM0ZOWPHTiaiPdniE9aTymsDJWze8k4SD8UfFjW9CCW3h5eZo7QgHj Zd8y08ht7qhbhdLlZ+ZmiieR6XORb3vM8nm3LSfgJ5KDTEFsImp4xG2HO5lcZjYFDDz5 rSn2aNBqRYujzlosCZMoXKB78y1WT4sJvzezAIwfGjBW+qvxkZlxmCnDEO1ArljwCTbh gg80ZFf8WGWia9/MNg0vW8C9JD74rOqQ6/6cn7v+yG3oWxK0XTnnoj7UIWF62GYauZsz BfvQ== X-Gm-Message-State: AGi0PubA9PQ3A34/3ZR6G5ls3+pq9VHX6hwpusWzrnf8fT8T+PWj3RK+ ei8NPKhjTXwjvvGGbeU9WSy2sg== X-Google-Smtp-Source: APiQypJbY1uOcfqhXECjapoDNvjxQ+p7yxJMMo1seFLcbhpcLb0ieFKg+o1JEoEOyTU0pOKfA9+86A== X-Received: by 2002:aa7:94a3:: with SMTP id a3mr4562496pfl.101.1587659175113; Thu, 23 Apr 2020 09:26:15 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id d12sm2841927pfq.36.2020.04.23.09.26.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Apr 2020 09:26:14 -0700 (PDT) From: Douglas Anderson To: linus.walleij@linaro.org, bgolaszewski@baylibre.com, airlied@linux.ie, daniel@ffwll.ch, robh+dt@kernel.org, narmstrong@baylibre.com, a.hajda@samsung.com, Laurent.pinchart@ideasonboard.com, spanda@codeaurora.org Cc: swboyd@chromium.org, devicetree@vger.kernel.org, linux-gpio@vger.kernel.org, jeffrey.l.hugo@gmail.com, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, robdclark@chromium.org, jernej.skrabec@siol.net, jonas@kwiboo.se, bjorn.andersson@linaro.org, Douglas Anderson , Sam Ravnborg , Thierry Reding , linux-kernel@vger.kernel.org Subject: [PATCH v3 3/6] drm/panel-simple: Support hpd-gpios for delaying prepare() Date: Thu, 23 Apr 2020 09:25:45 -0700 Message-Id: <20200423092431.v3.3.I53fed5b501a31e7a7fa13268ebcdd6b77bd0cadd@changeid> X-Mailer: git-send-email 2.26.1.301.g55bc3eb7cb9-goog In-Reply-To: <20200423162548.129661-1-dianders@chromium.org> References: <20200423162548.129661-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org People use panel-simple when they have panels that are builtin to their device. In these cases the HPD (Hot Plug Detect) signal isn't really used for hotplugging devices but instead is used for power sequencing. Panel timing diagrams (especially for eDP panels) usually have the HPD signal in them and it acts as an indicator that the panel is ready for us to talk to it. Sometimes the HPD signal is hooked up to a normal GPIO on a system. In this case we need to poll it in the correct place to know that the panel is ready for us. In some system designs the right place for this is panel-simple. When adding this support, we'll account for the case that there might be a circular dependency between panel-simple and the provider of the GPIO. The case this was designed for was for the "ti-sn65dsi86" bridge chip. If HPD is hooked up to one of the GPIOs provided by the bridge chip then in our probe function we'll always get back -EPROBE_DEFER. Let's handle this by allowing this GPIO to show up late if we saw -EPROBE_DEFER during probe. NOTE: since the gpio_get_optional() is used, if the "hpd-gpios" isn't there our variable will just be NULL and we won't do anything in prepare(). Signed-off-by: Douglas Anderson Reviewed-by: Stephen Boyd Reviewed-by: Linus Walleij --- Changes in v3: - Remind how gpio_get_optional() works in the commit message. Changes in v2: - ("simple...hpd-gpios") is 1/2 of replacement for ("Allow...bridge GPIOs") drivers/gpu/drm/panel/panel-simple.c | 53 ++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c index 3ad828eaefe1..f816e2aa29cd 100644 --- a/drivers/gpu/drm/panel/panel-simple.c +++ b/drivers/gpu/drm/panel/panel-simple.c @@ -23,6 +23,7 @@ #include #include +#include #include #include #include @@ -108,6 +109,7 @@ struct panel_simple { struct i2c_adapter *ddc; struct gpio_desc *enable_gpio; + struct gpio_desc *hpd_gpio; struct drm_display_mode override_mode; }; @@ -259,11 +261,37 @@ static int panel_simple_unprepare(struct drm_panel *panel) return 0; } +static int panel_simple_get_hpd_gpio(struct device *dev, + struct panel_simple *p, bool from_probe) +{ + int err; + + p->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN); + if (IS_ERR(p->hpd_gpio)) { + err = PTR_ERR(p->hpd_gpio); + + /* + * If we're called from probe we won't consider '-EPROBE_DEFER' + * to be an error--we'll leave the error code in "hpd_gpio". + * When we try to use it we'll try again. This allows for + * circular dependencies where the component providing the + * hpd gpio needs the panel to init before probing. + */ + if (err != -EPROBE_DEFER || !from_probe) { + dev_err(dev, "failed to get 'hpd' GPIO: %d\n", err); + return err; + } + } + + return 0; +} + static int panel_simple_prepare(struct drm_panel *panel) { struct panel_simple *p = to_panel_simple(panel); unsigned int delay; int err; + int hpd_asserted; if (p->prepared) return 0; @@ -282,6 +310,26 @@ static int panel_simple_prepare(struct drm_panel *panel) if (delay) msleep(delay); + if (p->hpd_gpio) { + if (IS_ERR(p->hpd_gpio)) { + err = panel_simple_get_hpd_gpio(panel->dev, p, false); + if (err) + return err; + } + + err = readx_poll_timeout(gpiod_get_value_cansleep, p->hpd_gpio, + hpd_asserted, hpd_asserted, + 1000, 2000000); + if (hpd_asserted < 0) + err = hpd_asserted; + + if (err) { + dev_err(panel->dev, + "error waiting for hpd GPIO: %d\n", err); + return err; + } + } + p->prepared = true; return 0; @@ -462,6 +510,11 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc) panel->desc = desc; panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd"); + if (!panel->no_hpd) { + err = panel_simple_get_hpd_gpio(dev, panel, true); + if (err) + return err; + } panel->supply = devm_regulator_get(dev, "power"); if (IS_ERR(panel->supply))