how to use devices in demo kernel

[dluberger]

I've reverted back to the demo sdcard image in order to verify wifi is working, and it is on the eval board. i loaded the same sd card into my custom board and used my custom device tree file, but now my matrix keypad isn't showing up as an input device. my guess is that maybe it's because the imx-keypad input device support was disabled for the kernel that was compiled for the imx6ulevk kernel image. I tried replacing the kernel with my own kernel i compiled using imx_v7_defconfig and with wifi and keypad support enabled in menuconfig, but now my kernel no longer works with the eval board (running "ifconfig wlan0 up" after boot no longer loads the wifi module).

How can i enable the imx matrix keypad input device setup in my device tree using the demo kernel? i don't want to recompile the kernel because it appears there is no version of the kernel source that natively supports the murata wifi modules.  My hardware isn't all that different from the eval board (mostly just no i2c sensors, and i'm using the KPP instead of the FEC) so it seems to me I should simply have to have a customized device tree based on the eval board device tree with the pertinent devices enabled or disabled.

[dluberger · Accepted solution]

There are a couple of peripherals, namely the matrix keypad and i2c2 port that simply don't work on my processor.  Neither of these seem to be complicated in hardware, but i never did get them to work.  I could get i2c1 to work so i moved all my i2c devices to that port.  The keypad port, when it comes up at all, only gives a constant stream of the same key, as though the processor thinks that key is being pressed and held down.  I can't see anything wrong with my schematic or pcb layout, so i can only figure there's some piece of config info that i need that's just not being provided anywhere, which, unfortunately, doesn't surprise me at this point because documentation has been so sparse but convoluted.

At this point I've abandoned the use of i2c2 and the matrix keypad port, and i'm now using a separate keypad controller attached to i2c1.

[gusarambula]

Hello David Luberger,

Switching the Device Tree should be enough to describe the Hardware changes to the Kernel. However, some devices require certain Kernel extensions enabled and you would need to make sure that the kernel does have support for them.

You would need to check if some extensions are missing and in that case edit the menuconfig options. You can do this inside Yocto or outside the Yocto environment.

If you are interested in changing the menuconfig options in Yocto the following document may be of help.

https://community.nxp.com/docs/DOC-334088

Regards,