From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH V5 05/12] Documentation: Add DT bindings for panel-lvds driver Date: Fri, 18 Jul 2014 00:48:11 +0200 Message-ID: <20140717224809.GA8875@mithrandir> References: <1405629839-12086-1-git-send-email-ajaykumar.rs@samsung.com> <1405629839-12086-6-git-send-email-ajaykumar.rs@samsung.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="CE+1k2dSO48ffgeK" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-samsung-soc-owner@vger.kernel.org To: Ajay kumar Cc: "devicetree@vger.kernel.org" , Ajay Kumar , "dri-devel@lists.freedesktop.org" , "linux-samsung-soc@vger.kernel.org" , InKi Dae , Rob Clark , Daniel Vetter , Sean Paul , Jingoo Han , sunil joshi , Prashanth G , Javier Martinez Canillas List-Id: devicetree@vger.kernel.org --CE+1k2dSO48ffgeK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jul 18, 2014 at 02:20:39AM +0530, Ajay kumar wrote: > +devicetree@vger.kernel.org >=20 > On Fri, Jul 18, 2014 at 2:13 AM, Ajay Kumar wr= ote: > > Add DT binding documentation for panel-lvds driver. > > > > Signed-off-by: Ajay Kumar > > --- > > .../devicetree/bindings/panel/panel-lvds.txt | 50 ++++++++++++= ++++++++ > > 1 file changed, 50 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/panel/panel-lvds.= txt > > > > diff --git a/Documentation/devicetree/bindings/panel/panel-lvds.txt b/D= ocumentation/devicetree/bindings/panel/panel-lvds.txt > > new file mode 100644 > > index 0000000..fdf91da2 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/panel/panel-lvds.txt > > @@ -0,0 +1,50 @@ > > +panel interface for eDP/lvds panels > > + > > +Required properties: > > + - compatible: "panel-lvds" I think I've said this before. I oppose the addition of this binding. We need to list a device-specific compatible value here, wildcards like this aren't a good choice. And then if we have that compatible value we can move most of the optional properties below into a driver. > > +Optional properties: If all these properties are optional, then what happens if a device tree node doesn't contain any of them? Doesn't that turn the driver into one big no-op? > > + -lcd-enable-gpios: > > + panel LCD poweron GPIO. > > + Indicates which GPIO needs to be powered up as = output > > + to powerup/enable the switch to the LCD panel. > > + -backlight-enable-gpios: > > + panel LED enable GPIO. > > + Indicates which GPIO needs to be powered up as = output > > + to enable the backlight. I've also said before that this really belongs in a backlight driver. Chances are that you'll want to have a way to set the brightness of the backlight as well, so simply an enable GPIO won't be good enough. > > + -panel-prepare-delay: > > + delay value in ms required for panel_prepare process > > + Delay in ms needed for the panel LCD unit to > > + powerup completely. > > + ex: delay needed till eDP panel throws HPD. > > + delay needed so that we cans tart reading e= did. If the panel signals HPD then we don't need this delay at all and we should just wait for HPD instead. > > + -panel-enable-delay: > > + delay value in ms required for panel_enable process > > + Delay in ms needed for the panel backlight/LED = unit > > + to powerup, and delay needed between video_enab= le and > > + backlight_enable. > > + -panel-disable-delay: > > + delay value in ms required for panel_disable process > > + Delay in ms needed for the panel backlight/LED = unit > > + powerdown, and delay needed between backlight_d= isable > > + and video_disable. > > + -panel-unprepare-delay: > > + delay value in ms required for panel_post_disable proce= ss > > + Delay in ms needed for the panel LCD unit to > > + to powerdown completely, and the minimum delay = needed > > + before powering it on again. These delays are all panel specific and they don't vary per board, so they shouldn't go into the device tree at all. > > + -panel-width-mm: physical panel width [mm] > > + -panel-height-mm: physical panel height [mm] Same here. 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