I have been using a custom LCD display on a beaglebone black running a 3.8
kernel using the DA8xx framebuffer.
I am now trying a new kernel with the TILCDC DRM driver. So I have built a
new kernel with the TILCDC driver enabled and have disabled DA8xx
framebuffer support.
I have modified my device tree to include the following.
panel {
compatible = "ti,tilcdc,panel";
pinctrl-names = "default";
pinctrl-0 = <&lcd_pins_s0>;
status = "okay";
panel-info {
bpp = <16>;
ac-bias = <255>;
ac-bias-intrpt = <0>;
dma-burst-sz = <16>;
fdd = <0x80>;
sync-edge = <1>;
sync-ctrl = <1>;
raster-order = <0>;
fifo-th = <0>;
invert-pxl-clk;
};
display-timings {
native-mode = <&timing0>;
timing0: 480x800 {
bpp = <16>;
clock-frequency = <28000000>;
hactive = <480>;
vactive = <800>;
hfront-porch = <1>;
hback-porch = <20>;
hsync-len = <1>;
vback-porch = <11>;
vfront-porch = <9>;
vsync-len = <10>;
hsync-active = <1>;
vsync-active = <1>;
};
};
};
The display timings and pinmux settings are the working values from the
DA8xx framebuffer.
On booting the kernel I get the following snippets.
[ 1.273229] [drm] Initialized drm 1.1.0 20060810
[ 1.784763] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 1.791771] [drm] No driver support for vblank timestamp query.
[ 1.805890] tilcdc 4830e000.lcdc: fb0: frame buffer device
[ 1.811792] tilcdc 4830e000.lcdc: registered panic notifier
[ 1.817647] [drm] Initialized tilcdc 1.0.0 20121205 on minor 0
running fbset gives me the following info
mode "480x800"
geometry 480 800 480 800 16
timings 0 0 0 0 0 0 0
accel true
rgba 5/11,6/5,5/0,0/0
endmode
Obviously the timings are wrong.
I have the following listed in /sys/class/drm
lrwxrwxrwx 1 root root 0 Jan 16 07:17 card0 ->
../../devices/ocp.3/4830e000.lcdc/drm/card0/
lrwxrwxrwx 1 root root 0 Jan 16 07:17 card0-LVDS-1 ->
../../devices/ocp.3/4830e000.lcdc/drm/card0/card0-LVDS-1/
lrwxrwxrwx 1 root root 0 Jan 16 07:17 controlD64 ->
../../devices/ocp.3/4830e000.lcdc/drm/controlD64/
further more.
cat /sys/class/drm/card0-LVDS-1/status
connected
cat /sys/class/drm/card0-LVDS-1/enabled
disabled
My problem is that it is not enabled.
I am assuming I need to pass some sort of "video=" to the kernel from
uboot, but I have no idea what.
Is there some other configuration I am missing ?
Has anyone else got this driver to work with an LCD panel ?
many thanks
Ben
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