From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Cercueil Subject: Re: [PATCH 1/3] dt-bindings: Add doc for the ingenic-drm driver Date: Fri, 01 Mar 2019 19:40:42 -0300 Message-ID: <1551480042.1526.0@crapouillou.net> References: <20190228220756.20262-1-paul@crapouillou.net> <20190228220756.20262-2-paul@crapouillou.net> <20190301201624.GA22317@ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20190301201624.GA22317@ravnborg.org> Sender: linux-kernel-owner@vger.kernel.org To: Sam Ravnborg Cc: David Airlie , Daniel Vetter , Rob Herring , Mark Rutland , Maarten Lankhorst , Maxime Ripard , Sean Paul , devicetree@vger.kernel.org, linux-mips@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org Hi Sam, thanks for the feedback. Le ven. 1 mars 2019 =E0 17:16, Sam Ravnborg a =E9crit : > Hi Paul. >=20 > Good to see work migrating fbdev =3D> drm. >=20 > Following comments is based on experience while working on migrating > another driver from fbdev =3D> drm. >=20 > On Thu, Feb 28, 2019 at 07:07:54PM -0300, Paul Cercueil wrote: >> Add documentation for the devicetree bindings of the DRM driver for=20 >> the >> JZ47xx family of SoCs from Ingenic. >>=20 >> Signed-off-by: Paul Cercueil >> Tested-by: Artur Rojek >> --- >> .../devicetree/bindings/display/ingenic,drm.txt | 30=20 >> ++++++++++++++++++++++ >> 1 file changed, 30 insertions(+) >> create mode 100644=20 >> Documentation/devicetree/bindings/display/ingenic,drm.txt >>=20 >> diff --git=20 >> a/Documentation/devicetree/bindings/display/ingenic,drm.txt=20 >> b/Documentation/devicetree/bindings/display/ingenic,drm.txt >> new file mode 100644 >> index 000000000000..52a368ec35cd >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/display/ingenic,drm.txt >> @@ -0,0 +1,30 @@ >> +Ingenic JZ47xx DRM driver >> + >> +Required properties: >> +- compatible: one of: >> + * ingenic,jz4740-drm >> + * ingenic,jz4725b-drm >> +- reg: LCD registers location and length > The fbdev way of doing this was to hardcode register setttings. > In the drm world we read the configuration of the panel and let > this decide the actual configuration. >=20 > Note that no drm drivers supports stn displays and that there > is really no use for this these days. So you can skip the STN parts. STN panels aren't really my problem; but I have a board with a Sharp LS020B1DD01D panel, which requires the LCD IP to be configured for a "special 2" panel. I also have a board with a "smart" panel (ili9331) that needs a special configuration in the IP. There is nothing in the drm_panel interface that tells me what mode I should use for what panel... > Also the modern way to specify a panel in the DT is using OF graph=20 > bindings. > You can find many examples how to do this. Ok, I was looking at the Tegra driver, which uses a "nvidia,panel" DT property. I will change it to use the graph thing. > I was there with the atmel LCDC driver (not in the kernel yet), > and had some challenges with this. >=20 > Sam Thanks, -Paul =