From patchwork Thu May 7 21:34:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 11534949 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 2EA1914B4 for ; Thu, 7 May 2020 21:35:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1403020CC7 for ; Thu, 7 May 2020 21:35:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="UxYcP2Wv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727770AbgEGVfn (ORCPT ); Thu, 7 May 2020 17:35:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727100AbgEGVfd (ORCPT ); Thu, 7 May 2020 17:35:33 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26EBAC05BD43 for ; Thu, 7 May 2020 14:35:32 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id y25so3647676pfn.5 for ; Thu, 07 May 2020 14:35:32 -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=N1E8hpQtZ5Dwx/KP93WpgOlFW3tR/zc7YU1QsvmgG9E=; b=UxYcP2WvfAqPASGNjeeemSarAPyqIB5ndoLfcsfFgS9gQOwJrFk2aKOh1KzGZYYy82 MVqQM2Z9Eu6nEAMRz38aA8GtbyhtKb1LBugXREv71ZH7Kuhn4AiB/nQodsQk699Pd4iK LBd1QBUUbblSZzVCQcLBA0Dui7ESeYRg5Gc9Q= 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=N1E8hpQtZ5Dwx/KP93WpgOlFW3tR/zc7YU1QsvmgG9E=; b=LZnqTN1lF+fQEUcYZpvICzgwD4f1bMqutTac51fKgxDq9Haua3vfTHqS9ruYXOC1we o5ayerSLCeAAX0TUZ3CxOdDIX8FpD/yxjz+W/CeHiZlroHR3ntj950iWKbPGzWDk9sRw nyH4oLwKQzkQkzywwhsIbRqRxbKbJhxfENMXc99FAZKA4dkOg5CyvuRghCR9hrrGJtFT ie1bCcz5q6KQtKNi+A4aoxLuMpRKTVmxwdk6vEHZKZIZdyfVHMZjt5WntYss/nxE3nV2 IYSayk7yI8CJ28wKAXsgMWklNOv+WxO6D8Lu2nMfWJtc1gE5YrOlGrzQ4rEBqcZq8Qcz NvOA== X-Gm-Message-State: AGi0PubY1CVAW3I0bgZA9YZF3QFmSCKF2Y5VN02jfpy/Xp6xUJmpjP5I V/Jav7uqAcQpK+VwM3OVlIv1HQ== X-Google-Smtp-Source: APiQypJf8281mnDUYU9yJA5Uh+czWYF/8KtOZ4222MJHsTw/dKf4hUC4S7EBQIFd2vuunMvdXj/GFA== X-Received: by 2002:a63:f960:: with SMTP id q32mr12548727pgk.357.1588887330910; Thu, 07 May 2020 14:35:30 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id i10sm5884860pfa.166.2020.05.07.14.35.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 May 2020 14:35:30 -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 Cc: jonas@kwiboo.se, jeffrey.l.hugo@gmail.com, linux-gpio@vger.kernel.org, bjorn.andersson@linaro.org, swboyd@chromium.org, jernej.skrabec@siol.net, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, robdclark@chromium.org, Douglas Anderson , Sam Ravnborg , Thierry Reding , linux-kernel@vger.kernel.org Subject: [PATCH v5 3/6] drm/panel-simple: Support hpd-gpios for delaying prepare() Date: Thu, 7 May 2020 14:34:57 -0700 Message-Id: <20200507143354.v5.3.I53fed5b501a31e7a7fa13268ebcdd6b77bd0cadd@changeid> X-Mailer: git-send-email 2.26.2.645.ge9eca65c58-goog In-Reply-To: <20200507213500.241695-1-dianders@chromium.org> References: <20200507213500.241695-1-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 v5: None 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))