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References: <20220608094816.2898692-1-hsinyi@chromium.org> <20220608094816.2898692-9-hsinyi@chromium.org>
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From:   Doug Anderson <dianders@chromium.org>
Date:   Wed, 8 Jun 2022 07:16:51 -0700
Message-ID: <CAD=FV=VShXpy+6ESXGKhw5Z9o3hfXNV2_HvdOAPM3YN2qSA9Sg@mail.gmail.com>
Subject: Re: [PATCH v6 8/8] drm: Config orientation property if panel provides it
To:     Hsin-Yi Wang <hsinyi@chromium.org>
Cc:     Hans de Goede <hdegoede@redhat.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Rob Clark <robdclark@chromium.org>,
        Rob Herring <robh+dt@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>
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Precedence: bulk

Hi,

On Wed, Jun 8, 2022 at 2:48 AM Hsin-Yi Wang <hsinyi@chromium.org> wrote:
>
> @@ -269,6 +280,31 @@ void drm_panel_bridge_remove(struct drm_bridge *bridge)
>  }
>  EXPORT_SYMBOL(drm_panel_bridge_remove);
>
> +/**
> + * drm_panel_bridge_set_orientation - Set the connector's panel orientation
> + * if the bridge is a panel bridge.
> + *
> + * @connector: The connector to be set panel orientation.
> + * @bridge: The drm_bridge to be transformed to panel bridge.

Ideally you should have a kernel doc to describe what you're returning.


> + */
> +int drm_panel_bridge_set_orientation(struct drm_connector *connector,
> +                                    struct drm_bridge *bridge)
> +{
> +       struct panel_bridge *panel_bridge;
> +
> +       if (!bridge)
> +               return 0;
> +
> +       if (bridge->funcs != &panel_bridge_bridge_funcs)
> +               return 0;

nit: Why do you need to handle NULL bridge and the case that someone
calls you with something other than a panel-bridge? I'm not convinced
that's useful. In general kernel style doesn't do massive validation
of parameters unless there's a reason for it. ...if we do need to
handle them then it feels like they should be returning -EINVAL or
something, not 0.


> @@ -917,10 +917,13 @@ void drm_bridge_hpd_notify(struct drm_bridge *bridge,
>                            enum drm_connector_status status);
>
>  #ifdef CONFIG_DRM_PANEL_BRIDGE
> +bool drm_bridge_is_panel(const struct drm_bridge *bridge);
>  struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
>  struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
>                                               u32 connector_type);
>  void drm_panel_bridge_remove(struct drm_bridge *bridge);
> +int drm_panel_bridge_set_orientation(struct drm_connector *connector,
> +                                     struct drm_bridge *bridge);

I suspect that you need some dummy versions of your new functions
defined if "CONFIG_DRM_PANEL_BRIDGE" is not defined. Otherwise we're
going to be yelled at by the kernel robot eventually.

-Doug