From patchwork Wed Sep 1 20:19:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 12470177 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9DB2C19F3A for ; Wed, 1 Sep 2021 20:20:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B49636109E for ; Wed, 1 Sep 2021 20:20:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245426AbhIAUVd (ORCPT ); Wed, 1 Sep 2021 16:21:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55284 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245154AbhIAUVc (ORCPT ); Wed, 1 Sep 2021 16:21:32 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 639BAC0617AE for ; Wed, 1 Sep 2021 13:20:28 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id w7so620420pgk.13 for ; Wed, 01 Sep 2021 13:20:28 -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=MFz/J7aAijkpNMg5cMsZk7y0NR1FdTOY1jwRJZxc2nE=; b=f5Rs2FjUW6nkR+AHabo7d9WoP1/vWzHJZv9+bW4me5pWqFLdEYjIS+1PUPQ+PFZ2+F uZ4RJoMTRSOrTb4aB9brFgTboAtAPRO4wfnaMb86fjyTkkJcnxUE47msuUGg7A3aj9H4 qevn5ZG395T+ZN4kb2Qr3SSsuEgZRbY290rn8= 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=MFz/J7aAijkpNMg5cMsZk7y0NR1FdTOY1jwRJZxc2nE=; b=X22CYSLZFbMRhi1Bw3xLz0wKLganF0q97AY1ucYGcqybWunL6FGZFTJqn9y6nyHTyE 8UGUooHhxNuIpx0UvGY2T9Bwo6NZjbnIhvAoShdChC+v7GuO6xUw4CLVidI5xGF7Jjjy CZiHSZL7pY9MP+GOUnj7XbqIXyb2WVv8rNvZNN1q/uKNrurpfoU4TSDpv5PTMZRsOyk3 HVdyuZlvCXD8iYyvLHwFIqIgQkpniISnogurQjV1Ln+9QEvlsnVRKMU52X3yGGDnoZHd 0JqKiInYkm26G6xKPs61h8eZqmUeiMZdZwU9CfKWMKcoaDOiHHCsJ4IopMI6ic66x1ay AslA== X-Gm-Message-State: AOAM531LN/Hbjc+olCZd80R8/Y/rsNf5jB/5GLRHKljRjw+qMVmYtkHo R+fC8roS4gEQ5V9zGImi+hm2fQ== X-Google-Smtp-Source: ABdhPJzG561MW4j1aGa/s8L4HHSGGsl+PzC3APu3L1sVM4dFh/eFb6YO0xt2ZtmTRVxRFQ3ueRbOrg== X-Received: by 2002:a63:4b53:: with SMTP id k19mr783896pgl.3.1630527627758; Wed, 01 Sep 2021 13:20:27 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:201:958b:b561:a735:e774]) by smtp.gmail.com with ESMTPSA id x15sm321178pfq.31.2021.09.01.13.20.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Sep 2021 13:20:27 -0700 (PDT) From: Douglas Anderson To: Thierry Reding , Rob Herring , Sam Ravnborg Cc: Maarten Lankhorst , linux-arm-msm@vger.kernel.org, Bjorn Andersson , Linus W , Daniel Vetter , devicetree@vger.kernel.org, Steev Klimaszewski , Thomas Zimmermann , Maxime Ripard , David Airlie , dri-devel@lists.freedesktop.org, Douglas Anderson , Rob Herring , linux-kernel@vger.kernel.org Subject: [PATCH v3 01/16] dt-bindings: drm/panel-simple-edp: Introduce generic eDP panels Date: Wed, 1 Sep 2021 13:19:19 -0700 Message-Id: <20210901131531.v3.1.I1116e79d34035338a45c1fc7cdd14a097909c8e0@changeid> X-Mailer: git-send-email 2.33.0.259.gc128427fd7-goog In-Reply-To: <20210901201934.1084250-1-dianders@chromium.org> References: <20210901201934.1084250-1-dianders@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org eDP panels generally contain almost everything needed to control them in their EDID. This comes from their DP heritage were a computer needs to be able to properly control pretty much any DP display that's plugged into it. The one big issue with eDP panels and the reason that we need a panel driver for them is that the power sequencing can be different per panel. While it is true that eDP panel sequencing can be arbitrarily complex, in practice it turns out that many eDP panels are compatible with just some slightly different delays. See the contents of the bindings file introduced in this patch for some details. The fact that eDP panels are 99% probable and that the power sequencing (especially power up) can be compatible between many panels means that there's a constant desire to plug multiple different panels into the same board. This could be for second sourcing purposes or to support multiple SKUs (maybe a 11" and a 13", for instance). As discussed [1], it should be OK to support this by adding two properties to the device tree to specify the delays needed for powering up the panel the first time. We'll create a new "edp-panel" bindings file and define the two delays that might need to be specified. NOTE: in the vast majority of the cases (HPD is hooked up and isn't glitchy or is debounced) even these delays aren't needed. [1] https://lore.kernel.org/r/CAD=FV=VZYOMPwQZzWdhJGh5cjJWw_EcM-wQVEivZ-bdGXjPrEQ@mail.gmail.com Signed-off-by: Douglas Anderson Reviewed-by: Rob Herring --- (no changes since v2) Changes in v2: - No longer allow fallback to panel-simple. - Add "-ms" suffix to delays. .../bindings/display/panel/panel-edp.yaml | 188 ++++++++++++++++++ 1 file changed, 188 insertions(+) create mode 100644 Documentation/devicetree/bindings/display/panel/panel-edp.yaml diff --git a/Documentation/devicetree/bindings/display/panel/panel-edp.yaml b/Documentation/devicetree/bindings/display/panel/panel-edp.yaml new file mode 100644 index 000000000000..6a621376ff86 --- /dev/null +++ b/Documentation/devicetree/bindings/display/panel/panel-edp.yaml @@ -0,0 +1,188 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/display/panel/panel-edp.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Probable (via DP AUX / EDID) eDP Panels with simple poweron sequences + +maintainers: + - Douglas Anderson + +description: | + This binding file can be used to indicate that an eDP panel is connected + to a Embedded DisplayPort AUX bus (see display/dp-aux-bus.yaml) without + actually specifying exactly what panel is connected. This is useful for + the case that more than one different panel could be connected to the + board, either for second-sourcing purposes or to support multiple SKUs + with different LCDs that hook up to a common board. + + As per above, a requirement for using this binding is that the panel is + represented under the DP AUX bus. This means that we can use any + information provided by the DP AUX bus (including the EDID) to identify + the panel. We can use this to identify display size, resolution, and + timings among other things. + + One piece of information about eDP panels that is typically _not_ + provided anywhere on the DP AUX bus is the power sequencing timings. + This is the reason why, historically, we've always had to explicitly + list eDP panels. We solve that here with two tricks. The "worst case" + power on timings for any panels expected to be connected to a board are + specified in these bindings. Once we've powered on, it's expected that + the operating system will lookup the panel in a table (based on EDID + information) to figure out other power sequencing timings. + + eDP panels in general can have somewhat arbitrary power sequencing + requirements. However, even though it's arbitrary in general, the + vast majority of panel datasheets have a power sequence diagram that + looks the exactly the same as every other panel. Each panel datasheet + cares about different timings in this diagram but the fact that the + diagram is so similar means we can come up with a single driver to + handle it. + + These diagrams all look roughly like this, sometimes labeled with + slightly different numbers / lines but all pretty much the same + sequence. This is because much of this diagram comes straight from + the eDP Standard. + + __________________________________________________ + Vdd ___/: :\____ / + _/ : : \_____/ + ::: :<--T10-->::: + : +-----------------------+---------+---------+ + eDP -----------+ Black video | Src vid | Blk vid + + Display : +-----------------------+---------+---------+ + : _______________________:_________:_________: + HPD :| : : | + ___________| : : |_____________ + : : : : + Sink +-----------------------:---------:---------+ + AUX CH -----------+ AUX Ch operational : : +------------- + +-----------------------:---------:---------+ + : : : : + :: :: : : + Src main +------+------+--------------+---------+ + lnk data----------------+LnkTrn| Idle |Valid vid data| Idle/off+------------- + +------+------+--------------+---------+ + : :<-T6->:<-T8->: : + :__:: + LED_EN | | + _____________________________________| |____________________________ + : : + __________:__:_ + PWM | : : | + __________________________| : : |__________________________ + : : : : + _____________:__________:__:_:______ + Bklight ____/: : : : : :\____ + power _______/ :<---T13---->: : : :: \______________ + (Vbl) ::<---------T14--------->: :<-T15->:: + + The above looks fairly complex but, as per above, each panel only cares + about a subset of those timings. + +allOf: + - $ref: panel-common.yaml# + +properties: + compatible: + const: edp-panel + + hpd-reliable-delay-ms: + description: + A fixed amount of time that must be waited after powering on the + panel's power-supply before the HPD signal is a reliable way to know + when the AUX channel is ready. This is useful for panels that glitch + the HPD at the start of power-on. This value is not needed if HPD is + always reliable for all panels that might be connected. + + hpd-absent-delay-ms: + description: + The panel specifies that HPD will be asserted this many milliseconds + from power on (timing T3 in the diagram above). If we have no way to + measure HPD then a fixed delay of this many milliseconds can be used. + This can also be used as a timeout when waiting for HPD. Does not + include the hpd-reliable-delay, so if hpd-reliable-delay was 80 ms + and hpd-absent-delay was 200 ms then we'd do a fixed 80 ms delay and + then we know HPD would assert in the next 120 ms. This value is not + needed if HPD hooked up, either through a GPIO in the panel node or + hooked up directly to the eDP controller. + + backlight: true + enable-gpios: true + port: true + power-supply: true + no-hpd: true + hpd-gpios: true + +additionalProperties: false + +required: + - compatible + - power-supply + +examples: + - | + #include + #include + #include + + i2c { + #address-cells = <1>; + #size-cells = <0>; + + bridge@2d { + compatible = "ti,sn65dsi86"; + reg = <0x2d>; + + interrupt-parent = <&tlmm>; + interrupts = <10 IRQ_TYPE_LEVEL_HIGH>; + + enable-gpios = <&tlmm 102 GPIO_ACTIVE_HIGH>; + + vpll-supply = <&src_pp1800_s4a>; + vccio-supply = <&src_pp1800_s4a>; + vcca-supply = <&src_pp1200_l2a>; + vcc-supply = <&src_pp1200_l2a>; + + clocks = <&rpmhcc RPMH_LN_BB_CLK2>; + clock-names = "refclk"; + + no-hpd; + + ports { + #address-cells = <1>; + #size-cells = <0>; + + port@0 { + reg = <0>; + endpoint { + remote-endpoint = <&dsi0_out>; + }; + }; + + port@1 { + reg = <1>; + sn65dsi86_out: endpoint { + remote-endpoint = <&panel_in_edp>; + }; + }; + }; + + aux-bus { + panel { + compatible = "edp-panel"; + power-supply = <&pp3300_dx_edp>; + backlight = <&backlight>; + hpd-gpios = <&sn65dsi86_bridge 2 GPIO_ACTIVE_HIGH>; + hpd-reliable-delay-ms = <15>; + + port { + panel_in_edp: endpoint { + remote-endpoint = <&sn65dsi86_out>; + }; + }; + }; + }; + }; + };