Hi Robert, (kernel version: 4.19.50-ti-r20) When I try to config-pin P9.24 can and config-pin P9.26 can I got the following error: ERROR: open() for /sys/devices/platform/ocp/ocp:P9_24_pinmux/state failed ERROR: open() for /sys/devices/platform/ocp/ocp:P9_26_pinmux/state failed I found that…

Hi Robert, Can you please help with some suggestions how to resolve the issue? It is new to me with these overlays. Thank you, David

Hi @dzhou , sorry i’m confused, does CAN1 work out of the box with out touching config-pin? config-pin is used to quickly change the pinmux of pin’s on the fly. However when you load a device specific overlay, that ability is removed, as the overlay has a specific pinmux for the device, such that i…

Hi Robert, CAN1 works on BBBw with CAPE, and BBBw loaded with Stretch version. It needs to config-pins, too. Now, I couldn’t be sure. But I believe it needs config-pins. Regards, David

These two lines disable config-pin for those pins: beagleboard/bb.org-overlays/blob/master/src/arm/BB-CAN1-00A0.dts#L52-L53 P9_24_pinmux { status = "disabled"; }; /* P9_24: uart1_txd.d_can1_rx */ P9_26_pinmux { status = "disabled"; }; /* P9_26: uart1_rxd.d_can1_tx */ …

Hi Robert, We got CAN working. Buster (2019-07 version) is just fine without recompiling overlays. Just config pins. We have our end problem, the mode control is implemented on our board. After grounding the pin, it just worked. Thank you for your help, David

PIN_MUX P9_26 not

Embedded Linux Discussions

RobertCNelson September 16, 2020, 1:57pm 2

Hi @dzhou ,

When an overlay takes a pin for a specific function, the overlay disables the corresponding config-pin entry.

Regards,

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PIN_MUX P9_26 not

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