I’ve spent more than a day now trying to get a custom LCD cape to work with the latest BB-G Debian distribution (7.9, 3.8.13) and can’t say I’ve really made any progress though I have learned a few things.
The LCD is wired to be compatible with the 4D systems LCD7 though without the touchscreen, buttons, or LEDs. If I enable BB-BONE-LCD7-01:00A3 on boot then I get a mouse pointer in the middle of the screen but this slowly fades to a completely black screen. I was encouraged by this and figured I just had to change the timings in the device tree to match my specific LCD.
I downloaded the overlay sources from github/bb.org-overlays and as a test just copied BB-BONE-LCD7-01-00A3.dts to BB-BONE-LCD7-01-00A7.dts, changed the version string, compiled (with the updated dtc), installed, enabled (uEnv.txt) and rebooted. The overlay actually fails to load with a complaing that gpio0 is undefined. This is just a hint that things aren’t going to go well. The gpio0 reference is for one of the buttons which I don’t need. I tried removing the entries for the touchscreen and buttons but then I just get complains that the ‘display-timings’ node is missing.
The bottom line is that it doesn’t appear that the device tree sources at https://github.com/beagleboard/bb.org-overlays are built to work correctly with my kernel. In fact the notes at the bottom of the page all talk about 4.1 and no mention of 3.8. Are there corresponding sources for the 3.8 kernel or am I better off loading a 4.1 image? I’d prefer to stay with 3.8 as I have other hardware in this project that requires a driver that I haven’t tried yet with 4.1 but I’m willing to try if that’s the best way.
Just hoping for a little insight before I spend another day going down the wrong path.