Re: [PATCH v6 8/8] drm: Config orientation property if panel provides it - Hsin-Yi Wang

From: Hsin-Yi Wang <hsinyi@chromium.org>
To: Doug Anderson <dianders@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>
Subject: Re: [PATCH v6 8/8] drm: Config orientation property if panel provides it
Date: Thu, 9 Jun 2022 11:13:09 +0800	[thread overview]
Message-ID: <CAJMQK-hoecGwz3AmN7qdRhYCOzDXbaHZ2Fa2UCmWMFO7ouFGUg@mail.gmail.com> (raw)
In-Reply-To: <CAD=FV=VShXpy+6ESXGKhw5Z9o3hfXNV2_HvdOAPM3YN2qSA9Sg@mail.gmail.com>

On Wed, Jun 8, 2022 at 10:17 PM Doug Anderson <dianders@chromium.org> wrote:
>
> 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.

The only caller had checked it. I can remove the check here.

>
>
> > @@ -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

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