ocp:Px_yy_pinmux has no "state" and "driver"

General Discussion
1

Original BBB image, when I get into

/sys/devices/platform/ocp/ocp:Px_yy_pinmux, each folder has state and driver.
when I customize our image, added “am335x-bone-common-univ.dtsi”, /sys/devices/platform/ocp/ocp:Px_yy_pinmux shown up but we don’t have state and driver that we can’t change gpio alternate pin function.

Any one know what we are missing or what driver / dtb to show “state” up?

Many thanks,

2

load bone-pinmux-helper.ko worked.

But P9_22_pinmux still has no state while P9_21, P9_17, P9_18 has “state” as well. I am trying to config SPI0.

Not sure why!

3

Ive been trying to config SPI1 for use. I found that pinmux can get “disabled” during boot-up when the device tree blob files get read.
do a search of the source tree for “P9_22_pinmux”. My copy of bone-4.19.232.bone75 has KERNEL/arch/arm/boot/dts/am335x-bone-pinmux-spi0.dtsi disabling the pinmux on line 23. I don’t know your setup, or if that file is actually getting called, but it tripped me up a week or three ago.

4

Not sure why bone-pinmux-helper doesn’t work on some pins including P9_22.

5

In my setup, I haven’t done anything with spi0 yet.

I just build am335x-bone-common-univ.dtsi and load “bone-pinmux-helper”.

Because the config-pin looking for the state file in the path: /sys/devices/platform/ocp/ocp:Px_yy_pinmux

Most of the pins have the path correctly now, except for P9_22
So config-pin work with most of pins, except for P9_22 (and few more) because no state file where the alterate mode will be written to.

I need P9_22 because this is spi0 clock pin.

6

Go check out arch/arm/boot/dts/overlays/BB-SPIDEV0-00A0.dts
It not only disables pinmux but also sets the pin configuration(s) for you.
I have yet to try adding overlays to uEnv.txt, so you’ll have to let me know if adding it worked.

7

Hi, that will be next step.
For now, just not sure why config-pin work on P9_21 but not on P9_22

8

Hi, I found the issue why P9_22 doesn’t but other ones work!

Reason is, in SPI overlays we use:
…
0x150 0x30
0x154 0x30
0x158 0x10
0x15C 0x10
…

0x150 is P9_22 that hold by the overlay.
if I move 0x154 (P9_21) then P9_22 work but P9_21.

It make sense if all pin don’t work because hold for SPI0 once SPI0 active but only the top is hold, that doesn’t make sense to me.

Release to this issue: BB-SPIDEV0-00A0.dts take first pin only? - General Discussion - BeagleBoard