I would like to control PWM0( LCD_BL ) on L4T 24.2.1 Jetson Tx1 reference board.
i did try under link. but can not contorl pwm0.
https://devtalk.nvidia.com/default/topic/988669/?comment=5060881
i want detail guide plz
Hi walterkim
How do you verify the control not working. Did you probe the signal?
Below is my probe result.
cd /sys/class/pwm/pwmchip0
echo 0 > export
cd pwm0
echo 20000 > period (20us is the total time period of the pulse)
echo 10000 > duty_cycle (50% duty cycle)
echo 1 > enable
Could you send dts file and kernel config files?
i used jetson tx1 reference board
did you use jetson tx1?
i did try Pin number B27, Pin name LCD0_BKLT_PWM. is it right?
I did use jeston tx1 withd r24.2.1 without any change.
The Pin number is correct.
Your measure is correct. Did you probe any thing?
I installed JetPack-L4T-2.3.1-linux-x64.run to jetson tx1 reference board.
um…
no signal…
change jetson tx1 module and retry then same result no signal.
i cannot find differet.
my carrier board is bad???
I can’t tell what happen on your board. What the result to cat /sys/kernel/debug/pwm
Below is my result.
platform/7000a000.pwm, 4 PWM devices
pwm-0 (sysfs ): requested
pwm-1 (pwm-regulator ): requested enabled
pwm-2 ((null) ):
pwm-3 (pwm-fan.43 ): requested enabled
cat /sys/kernel/debug/pwm
platform/7000a000.pwm, 4 PWM devices
pwm-0 (sysfs ): requested enabled
pwm-1 (pwm-regulator ): requested enabled
pwm-2 ((null) ):
pwm-3 (pwm-fan.43 ): requested enabled
root@tegra-ubuntu:/sys/class/pwm/pwmchip0/pwm0#
Hi walterkim,
As for LCD_BL_PWM routing, no other devices on it except 2 connectors, J23 & J13, so it is hard to be damaged. Did you try probe pin head instead of foot? And you can remove module, simultaneously probe pin B27 of J13 and pin 10 of J23 to check the connection.