Tool/software:
Problem description:
I am unable to pull down the PNL_BackLight_CTRL pin and PNL_VDD_CTRL pin using the gpioset command or echo xxx/export, direction, value command
Requirement: How to pull up/down the GPIO pin while calling it in the device tree kernel?
Error message:
Hardware circuit design:
PNL_VDD_CTRL is connected to the SOC AB20 (GPO1_6) pin
PNL_BackLight_CTRL is connected to SOC AA21 (GPO1_3) pin
device tree
After power on, the PNL_VDD_CRL and PNL_BackLight_CTRL pins will be pulled high
Board side view GPIO status and regulator status commands
cat /sys/kernel/debug/gpio
cat /sys/kernel/debug/regulator/regulator_summary
Now when I detect that VCC is disconnected and the voltage is below the threshold, I need to pull down the PNL_VDD_CRL and PNL_BACK LIGHT pins, and the following error occurs at this stage:
03:00:03 MCU,(448 )operator(): Failed to set GPIO631 value.
Path: /sys/class/gpio/gpio631/value, Error: No such file or directory
03:00:03 MCU,(448 )operator(): Failed to set GPIO634 value.
Path: /sys/class/gpio/gpio634/value, Error: No such file or directory
I failed two debugging commands on the board, gpioset or echo xxx/export, direction, and value
Annotate this part of the code in the device tree, and it can be set through board side instructions. The problem is that in practical applications, it is necessary to raise the PNL_VDD_CRL and PNL_BackLight_CTRL pins in the kernel, rather than waiting until the application layer to raise them.
So how to achieve the effect of VCC disconnection and active screen shutdown while keeping the kernel driver to pull up the PNL_VDD_CRL and PNL_BackLight_CTRL pins and pulling them down at the application layer. Then we need to solve the issue of device or resource busy reported above
