[PATCH 11/11] ARM: versatile: move CLCD configuration to device tree

On 25/02/16 21:30, Linus Walleij wrote:

On Thu, Feb 25, 2016 at 5:45 PM, Tomi Valkeinen [off-list ref] wrote:

quoted

On 25/02/16 16:04, Linus Walleij wrote:

quoted

quoted

*All* the others
will be very happy with *ONE* display defined as panel in the
device tree, and off they go. Usually VGA. And that will look

You keep mentioning VGA. So is there are VGA output? Or do you just mean
MIPI DPI panels, which happen to take the same video timings as VGA?

Russell beat me to it, yes there is an external VGA encoder.
It needs some bits set up through the "misc registers" system
controller as indicated. From the CLCD hardware point of view
it's no different than any other panel. So the DTS fragment looks
like so:

                        panel {
                                compatible = "panel-dpi";

                                port {
                                        clcd_panel: endpoint {
                                                remote-endpoint = <&clcd_pads>;
                                        };
                                };

                                /* Standard 640x480 VGA timings */
                                panel-timing {
                                        clock-frequency = <25175000>;
                                        hactive = <640>;
                                        hback-porch = <48>;
                                        hfront-porch = <16>;
                                        hsync-len = <96>;
                                        vactive = <480>;
                                        vback-porch = <33>;
                                        vfront-porch = <10>;
                                        vsync-len = <2>;
                                };
                        };


This is reported as the default display type if no LCD panel
is connected.

If a LCD panel is also connected, it take precedence.

Ok. Well... It's all wrong, but I don't know how much time we want to
spend on fixing that.

Although one thing to consider is that if there is ever going to be a
DRM driver for CLCD, it would be good to have the device tree parts
correctly representing the hardware, so that the DRM driver could be
implemented in a cleaner, more generic way.

 Tomi

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