Set pins mode for kernel 3.8

Hello all,

I’m using BBB with latest Angtrom image.

I want to set pins mode for kernel 3.8, I’ve already googled and find this page: but it’s for older kernel.

I want to change some pins to PWM mode. For example, I want to set P8_34 and P8_36 to PWM mode. How to do?

Anyones know how to set mode for these pin please tell me.

Many thanks!


I have read device tree, and I did like the document show but I’m still getting only 8 devices, this is the result:


sh-4.2# cat /sys/kernel/debug/pwm
platform/48304100.ecap, 1 PWM device
pwm-0 ((null) ):

platform/48304200.ehrpwm, 2 PWM devices
pwm-0 ((null) ):
pwm-1 ((null) ):

platform/48302200.ehrpwm, 2 PWM devices
pwm-0 ((null) ):
pwm-1 ((null) ):

platform/48300100.ecap, 1 PWM device
pwm-0 ((null) ):

platform/48300200.ehrpwm, 2 PWM devices
pwm-0 ((null) ):
pwm-1 ((null) ):


I want to enable P8_34 PWM pin.

This is content of file: bone_pwm_P8_34-00A0.dts



  • Copyright © 2013 CircuitCo
  • Copyright © 2013 Texas Instruments


cat /sys/devices/bone_capemgr*/slots

0: 54:PF—
1: 55:PF—
2: 56:PF—
3: 57:PF—
4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
7: ff:P-O-L Override Board Name,00A0,Override Manuf,am33xx_pwm

8: ff:P-O-L Override Board Name,00A0,Override Manuf,bone_pwm_P8_13
9: ff:P-O-L Override Board Name,00A0,Override Manuf,bone_pwm_P9_21
10: ff:P-O-L Override Board Name,00A0,Override Manuf,bone_pwm_P9_42
11: ff:P-O-L Override Board Name,00A0,Override Manuf,bone_pwm_P9_14


I can enable P8_13, P8_21, P9_42, P9_14 but I can’t enable P8_34 and others else…

My problem is I want to enable 8 pins.

Ok man, I’ve disabled HDMI by modidying uEnv.txt


optargs=quiet drm.debug=7 capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN


and it’s working now. That’s what I need.

Thank you.