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From: Sean Paul <sean@poorly.run>
To: Douglas Anderson <dianders@chromium.org>
Cc: Sean Paul <seanpaul@chromium.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	Sandeep Panda <spanda@codeaurora.org>,
	linux-arm-msm@vger.kernel.org,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	jsanka@codeaurora.org, ryandcase@chromium.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org, Rob Herring <robh+dt@kernel.org>,
	David Airlie <airlied@linux.ie>,
	Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH 1/6] dt-bindings: drm/panel: simple: Add no-hpd property
Date: Thu, 25 Oct 2018 14:06:22 -0400	[thread overview]
Message-ID: <20181025175118.GJ154160@art_vandelay> (raw)
In-Reply-To: <20181022204639.8558-1-dianders@chromium.org>

On Mon, Oct 22, 2018 at 01:46:34PM -0700, Douglas Anderson wrote:
> Some eDP panels that are designed to be always connected to a board
> use their HPD signal to signal that they've finished powering on and
> they're ready to be talked to.
> 
> However, for various reasons it's possible that the HPD signal from
> the panel isn't actually hooked up.  In the case where the HPD isn't
> hooked up you can look at the timing diagram on the panel datasheet
> and insert a delay for the maximum amount of time that the HPD might
> take to come up.
> 
> Let's add a property in the device tree for this concept.
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Reviewed-by: Sean Paul <sean@poorly.run>

> ---
> 
>  .../devicetree/bindings/display/panel/simple-panel.txt         | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/simple-panel.txt b/Documentation/devicetree/bindings/display/panel/simple-panel.txt
> index 45a457ad38f0..b2b872c710f2 100644
> --- a/Documentation/devicetree/bindings/display/panel/simple-panel.txt
> +++ b/Documentation/devicetree/bindings/display/panel/simple-panel.txt
> @@ -11,6 +11,9 @@ Optional properties:
>  - ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing
>  - enable-gpios: GPIO pin to enable or disable the panel
>  - backlight: phandle of the backlight device attached to the panel
> +- no-hpd: This panel is supposed to communicate that it's ready via HPD
> +  (hot plug detect) signal, but the signal isn't hooked up so we should
> +  hardcode the max delay from the panel spec when powering up the panel.
>  
>  Example:
>  
> -- 
> 2.19.1.568.g152ad8e336-goog
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS

  parent reply	other threads:[~2018-10-25 18:06 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-22 20:46 Douglas Anderson
2018-10-22 20:46 ` [PATCH 2/6] drm/panel: simple: Support panels with HPD where HPD isn't connected Douglas Anderson
2018-10-25 18:08   ` Sean Paul
2018-10-22 20:46 ` [PATCH 3/6] drm/panel: simple: Add "no-hpd" delay for Innolux TV123WAM Douglas Anderson
2018-10-22 20:46 ` [PATCH 4/6] drm/bridge: ti-sn65dsi86: Remove the mystery delay Douglas Anderson
2018-10-25 18:10   ` Sean Paul
2018-10-22 20:46 ` [PATCH 5/6] drm/panel: simple: Innolux TV123WAM is actually P120ZDG-BF1 Douglas Anderson
2018-10-25 18:13   ` Sean Paul
2018-10-25 18:45     ` Doug Anderson
2018-10-25 19:25       ` Abhinav Kumar
2018-10-25 22:24     ` Doug Anderson
2018-10-26 14:38       ` Sean Paul
2018-10-22 20:46 ` [PATCH 6/6] dt-bindings: " Douglas Anderson
2018-10-25 18:15   ` Sean Paul
2018-10-25 19:49   ` Rob Herring
2018-10-25 18:06 ` Sean Paul [this message]
2018-10-25 19:28 ` [PATCH 1/6] dt-bindings: drm/panel: simple: Add no-hpd property Rob Herring

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