The engineer is having an issue connecting the PWM for the backlight. Here is his query.
Question. Is it enough to configure the PWM pin in pinmux, or do I need more PWM settings? And if so, in what part of the device tree?
Also, I found these posts but many of them don’t seem to resolve.
This is a thread that pertains to PWM that might be helpful. Please read through carefully as it’s a pretty long thread.
this one as well but alas it doesn’t seem to resolve and the issue seems pretty similar. is there a particular thread where this is resolved?
Me again; we moved the software stack to Jetson Nano 4g (compared to the earlier 2g), and the same problem emerged.
I did the full reflashing of the device to make sure that backlight pwm pin is assigned the appropriate function and settings.
In short, I see the following when I boot the device:
• devm 0x700031fc → 0x01
• devm 0x6000d504 → 0x02
Once I write:
devm 0x700031fc 8 0x45
I can run pwmchip0/pwm0 by hand and it works. How can I enforce this change to happen in device tree, and not manually?
Second part, when I put backlight-pwm driver on top of this pwm0_0, but it doesn’t work at all, with or without devm commands.
Any help is welcome.
Thanks in advance