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From:   Doug Anderson <dianders@chromium.org>
Date:   Thu, 7 May 2020 07:39:25 -0700
Message-ID: <CAD=FV=WHoxdr++f7Y_NO=VnrnEPkP=+WS5u3j_5ifEjekhBWcA@mail.gmail.com>
Subject: Re: [PATCH v4 1/6] drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux
To:     LinusW <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Sandeep Panda <spanda@codeaurora.org>
Cc:     "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Jonas Karlman <jonas@kwiboo.se>,
        Rob Clark <robdclark@chromium.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Jeffrey Hugo <jeffrey.l.hugo@gmail.com>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, Stephen Boyd <swboyd@chromium.org>,
        LKML <linux-kernel@vger.kernel.org>
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Hi,

On Thu, Apr 30, 2020 at 12:46 PM Douglas Anderson <dianders@chromium.org> wrote:
>
> The ti-sn65dsi86 MIPI DSI to eDP bridge chip has 4 pins on it that can
> be used as GPIOs in a system.  Each pin can be configured as input,
> output, or a special function for the bridge chip.  These are:
> - GPIO1: SUSPEND Input
> - GPIO2: DSIA VSYNC
> - GPIO3: DSIA HSYNC or VSYNC
> - GPIO4: PWM

One suggestion that came off-list is to change the code to make the
numbering match up better with the datasheet.  Right now if you want
GPIO 2 you have to refer to it like:

hpd-gpios = <&sn65dsi86_bridge 1 GPIO_ACTIVE_HIGH>;

That's because the code right now numbers things starting at 0 even if
the datasheet numbers things starting at 1.

I'm planning to spin the series later today for this.  While at it,
I'll squash my yaml bindings fixup into the bindings patch in this
series.  If someone would rather I wait and not spin yet, please yell.