From patchwork Thu Apr 30 19:46:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 11521377 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 D5CE581 for ; Thu, 30 Apr 2020 19:46:48 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B47E7207DD for ; Thu, 30 Apr 2020 19:46:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="mr8nNlcK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B47E7207DD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 098B46E952; Thu, 30 Apr 2020 19:46:44 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by gabe.freedesktop.org (Postfix) with ESMTPS id 38A956E94F for ; Thu, 30 Apr 2020 19:46:31 +0000 (UTC) Received: by mail-pl1-x641.google.com with SMTP id u22so2678482plq.12 for ; Thu, 30 Apr 2020 12:46:31 -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=18Forp5+g/d/pxVZSsn0tcdk9UfdWJp9klOtqj0eYRI=; b=mr8nNlcKXcCEZnkHZiBZidBV3UR0TJqCPNQtGgh1fQWaNgl85dgxydxCoz+9L1gnVh 2LNDZgHoAaTe8AHvtVJ4YRq6pEgMPId2Clwccx0CoPy5CTPfnEUZooODm35qX21xzB69 fR9dEgebGVLRbb1nDbdT27qFCYfKQV/OHsHvA= 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=18Forp5+g/d/pxVZSsn0tcdk9UfdWJp9klOtqj0eYRI=; b=Jp9CdgdCBCDEs1VVI6Kyy1R416IT+ZAw0SA0z+gUx6oLbHA8YZG3Os1L4INZIRP5wD LTG5QlfhugTsO7AqCT/0GTcBMwGIcmw2LYKoXk7gPBGr8CGzQNcVfAcn6GF9eQGj9v6F jLor+VT+ATdbcKtEOTK2wbeBwXWvI4mIILYrIItu6ByH8Umt2yr+UWTFEPtSjJ76+EvX yuHSzN5mSVDV24tJOpciif+jBz4HP1cxqg9STpErIeq3SwwNRoTdzpZnpqeN5Aa4DSyK AFwU0AHxkQvToB2A245LyRLkPuoa0wvLMBmyAMTFMHQ57hfk5hME21kF9cNg5QMK5qd1 6rYw== X-Gm-Message-State: AGi0Pub2a9dhua9ZBj7hlzpXG5fzkboUK9jN9WplVa2VmAwaMaayw4Op w8Wepb50sarJQYxQnevFC0VQwQ== X-Google-Smtp-Source: APiQypJiiPg0AHbv1LplSnQZRy3lAkJBvHGsUqdCPSJLVGyrcfUn4eezmereo9Kt5jX7p5OkOuJKlg== X-Received: by 2002:a17:90a:fb4e:: with SMTP id iq14mr486978pjb.146.1588275990734; Thu, 30 Apr 2020 12:46:30 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id u3sm495993pfb.105.2020.04.30.12.46.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Apr 2020 12:46:30 -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 Subject: [PATCH v4 3/6] drm/panel-simple: Support hpd-gpios for delaying prepare() Date: Thu, 30 Apr 2020 12:46:14 -0700 Message-Id: <20200430124442.v4.3.I53fed5b501a31e7a7fa13268ebcdd6b77bd0cadd@changeid> X-Mailer: git-send-email 2.26.2.526.g744177e7f7-goog In-Reply-To: <20200430194617.197510-1-dianders@chromium.org> References: <20200430194617.197510-1-dianders@chromium.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: robdclark@chromium.org, devicetree@vger.kernel.org, jernej.skrabec@siol.net, jeffrey.l.hugo@gmail.com, linux-arm-msm@vger.kernel.org, jonas@kwiboo.se, Douglas Anderson , dri-devel@lists.freedesktop.org, bjorn.andersson@linaro.org, linux-gpio@vger.kernel.org, Thierry Reding , swboyd@chromium.org, Sam Ravnborg , linux-kernel@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 v4: None 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))