于 2018年1月5日 GMT+08:00 上午2:52:10, Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> 写到: >On Wed, Jan 03, 2018 at 10:32:26PM +0100, Jernej Škrabec wrote: >> Hi Rob, >> >> Dne sreda, 03. januar 2018 ob 21:21:54 CET je Rob Herring napisal(a): >> > On Sat, Dec 30, 2017 at 10:01:58PM +0100, Jernej Skrabec wrote: >> > > This commit adds all necessary compatibles and descriptions >needed to >> > > implement A83T HDMI pipeline. >> > > >> > > Mixer is already properly described, so only compatible is added. >> > > >> > > However, A83T TCON1, which is connected to HDMI, doesn't have >channel 0, >> > > contrary to all TCONs currently described. Because of that, TCON >> > > documentation is extended. >> > > >> > > A83T features Synopsys DW HDMI controller with a custom PHY which >looks >> > > like Synopsys Gen2 PHY with few additions. Since there is no >> > > documentation, needed properties were found out through >experimentation >> > > and reading BSP code. >> > > >> > > At the end, example is added for newer SoCs, which features DE2 >and DW >> > > HDMI. >> > > >> > > Signed-off-by: Jernej Skrabec <jernej.skrabec@xxxxxxxx> >> > > --- >> > > >> > > .../bindings/display/sunxi/sun4i-drm.txt | 188 >> > > ++++++++++++++++++++- 1 file changed, 181 insertions(+), 7 >deletions(-) >> > > >> > > diff --git >a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt >> > > b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt >index >> > > 9f073af4c711..3eca258096a5 100644 >> > > --- >a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt >> > > +++ >b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt >> > > >> > > @@ -64,6 +64,40 @@ Required properties: >> > > first port should be the input endpoint. The second should >be the >> > > output, usually to an HDMI connector. >> > > >> > > +DWC HDMI TX Encoder >> > > +----------------------------- >> > > + >> > > +The HDMI transmitter is a Synopsys DesignWare HDMI 1.4 TX >controller IP >> > > +with Allwinner's own PHY IP. It supports audio and video outputs >and CEC. >> > > + >> > > +These DT bindings follow the Synopsys DWC HDMI TX bindings >defined in >> > > +Documentation/devicetree/bindings/display/bridge/dw_hdmi.txt >with the >> > > +following device-specific properties. >> > > + >> > > +Required properties: >> > > + >> > > + - compatible: value must be one of: >> > > + * "allwinner,sun8i-a83t-dw-hdmi" >> > > + - reg: two pairs of base address and size of memory-mapped >region, >> > > first >> > > + for controller and second for PHY >> > > + registers. >> > >> > Seems like the phy should be a separate node and use the phy >binding. >> > You can use the phy binding even if you don't use the kernel phy >> > framework... >> >> Unfortunately, it's not so straighforward. Phy is actually accessed >through >> I2C implemented in HDMI controller. Second memory region in this case >has >> small influence on phy. However, it has big influence on controller. >For >> example, magic number has to be written in one register in second >memory >> region in order to unlock read access to any register from first >memory region >> (controller). However, they shouldn't be merged to one region, >because first >> memory region requires byte access while second memory region can be >accessed >> per byte or word. >> >> To complicate things more, later I want to add support for another >SoC which >> has same glue layer (unlocking read access, etc.) and uses memory >mapped phy >> registers in second memory region. >> >> I think current binding is the least complicated way to represent >this. > >I agree with Rob here. I did a similar thing for the DSI patches I've >sent a few monthes ago and it turned out to not be that difficult, so >I'm sure you can come up with something :) In A83T/H3/A64/H5/R40 this part is not purely a PHY. It controls the access of main controller's register (e.g. read/write lock and register obfuscation). So it should be called a "glue" with PHY part (and on A83T seems a pure glue) but not a simple PHY. > >Maxime > >-- >Maxime Ripard, Free Electrons >Embedded Linux and Kernel engineering >http://free-electrons.com > >_______________________________________________ >linux-arm-kernel mailing list >linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
