Linux not detecting mux child i2c busses

Question

Hi,

In my custom Linux for Ultrazed, it does not detect the child i2c busses of the 9542 mux. I receive the following messages during boot.

[ 1.559359] i2c /dev entries driver

[ 1.563038] cdns-i2c ff030000.i2c: 400 kHz mmio ff030000 irq 32

[ 1.569687] pca954x 0-0070: registered 0 multiplexed busses for I2C mux pca9542

If I use the AVNET oroginal sd card image, it detects the child busses.

I've copied the kconfig and system_user.dtsi from the petalinux bsp into my own Yocto project.

Unfortunately I get different results.

Any idea what else I could be missing?

Thanks,

Richard.

rgb-sti · Accepted Answer

I've found the issue. The meta-xilinx layer I was using appears to relate to 2017.1 release. There was an update to the pca954x driver which resolves the issue. I'm not in a position to update the meta-xilinx layer right now, but applying a patch to the newer driver worked. [ 1.550760] i2c /dev entries driver [ 1.554445] cdns-i2c ff020000.i2c: 400 kHz mmio ff020000 irq 34 [ 1.560924] cdns-i2c ff030000.i2c: 400 kHz mmio ff030000 irq 35 [ 1.597693] i2c i2c-1: Added multiplexed i2c bus 2 [ 1.602625] i2c i2c-1: Added multiplexed i2c bus 3 [ 1.607343] pca954x 1-0070: registered 2 multiplexed busses for I2C mux pca9542 Thanks, Richard.