Hello, I have a RM520N module and I’m using the Quectel SDK to build images for it.
I would like to change the function of the LED_WWAN signal from its current purpose to acting as a GPIO. I would then like to programmatically control the GPIO.
Please could you let me know if that is possible?
Thank you! Ben.
Could you write the FW or SDK verison you are using, and the pin number, do you mean the PIN_STATUS for indicating the module’s operation status?
Thanks
Hi @Puck-Q ,
The SDK version is RM520NGLAAR03A01M4G_OCPU_BETA_20230619C_01.200.01.200
The pin I’m referring to is LED_WWAN, at pin 10 on RM520N.
Thank you.
You can try to modify the modem_cfg file in the SDK, and change the AD0100 to AD0101 to release the modem’s control, and make rootfs to update the rootfs image.
at+qagpio=1,3,1 // high level
at+qagpio=1,3,0 // low level
Or using sysfs,
echo 898 > /sys/class/gpio/exprot
cd gpio898
echo out > direction // output
echo 1 > value // high level
Thanks
Thank you for you answer @Puck-Q .
Unfortunately, that did not work. The GPIO state does not change when I control it from userspace. It appears to no longer be controlled by the modem, because the LED no longer turns on when the modem is connected, like it did before.
I changed the model_cfg file, you can see it being loaded in kernel boot log below with value AD0101.
[ 0.844164] [modem_cfg] open sucessfully
[ 0.844529] [modem_cfg] read_buf A00101A10101A20101A30101A40101A50101A60100A70101A80100A90101AA0101AB0100AC0100AD0101AE0100AF0100MQ
[ 0.844564] [modem_cfg] smem copy length=99
[ 0.844568] [modem_cfg] smem alloc sucessfully
Performing the steps you identified to control the GPIO from userspace:
/sys/class/gpio # ls
export gpiochip896 gpiochip912 gpiochip916 unexport
/sys/class/gpio # echo 898 > export
/sys/class/gpio # ls
export gpio898 gpiochip896 gpiochip912 gpiochip916 unexport
/sys/class/gpio # cd gpio898/
/sys/devices/platform/c440000.qcom,spmi/spmi-0/spmi0-01/c440000.qcom,spmi:qcom,pmx65@1:pinctrl@8800/gpiochip2/gpio/gpio898 # echo out > direction
/sys/devices/platform/c440000.qcom,spmi/spmi-0/spmi0-01/c440000.qcom,spmi:qcom,pmx65@1:pinctrl@8800/gpiochip2/gpio/gpio898 # cat direction
out
/sys/devices/platform/c440000.qcom,spmi/spmi-0/spmi0-01/c440000.qcom,spmi:qcom,pmx65@1:pinctrl@8800/gpiochip2/gpio/gpio898 # echo 1 > value
/sys/devices/platform/c440000.qcom,spmi/spmi-0/spmi0-01/c440000.qcom,spmi:qcom,pmx65@1:pinctrl@8800/gpiochip2/gpio/gpio898 # cat value
1
/sys/devices/platform/c440000.qcom,spmi/spmi-0/spmi0-01/c440000.qcom,spmi:qcom,pmx65@1:pinctrl@8800/gpiochip2/gpio/gpio898 # echo 0 > value
/sys/devices/platform/c440000.qcom,spmi/spmi-0/spmi0-01/c440000.qcom,spmi:qcom,pmx65@1:pinctrl@8800/gpiochip2/gpio/gpio898 # cat value
0
I did notice that 898 is mentioned in the kernel boot log, not sure if that is relevant to this issue?
[ 0.384062] quec_key c440000.qcom,spmi:qcom,pmx65@1:ql-pwrkey@8A00: key pmx65_gpio3: gpio=898; irq=101; code=116, wakeup=1, dbc=15
[ 0.384203] quec_key c440000.qcom,spmi:qcom,pmx65@1:ql-pwrkey@8A00: key pmx65_gpio14: gpio=909; irq=102; code=408, wakeup=1, dbc=15
Thank you.
Thank you for the feedback.
Let me check it internally and back to you ASAP.
Thanks
Thanks @Puck-Q , unfortunately that did not work, now, the system reboots when setting that GPIO to a low/0 value!
/sys/class/gpio # echo 909 > export
/sys/class/gpio # ls
export gpio909 gpiochip896 gpiochip912 gpiochip916 unexport
/sys/class/gpio # echo out > gpio909/direction
/sys/class/gpio # echo 1 > gpio909/value
/sys/class/gpio # echo 0 > gpio909/value
/sys/class/gpio #
# System reboots here
Sorry for the typo, it’s 908, my test here is normal.
WWAN_LED—PIN10—PMU_GPIO_3（sdx55）and PMU_GPIO_13(sdx6x)
The GPIO pins provided by the power control unit, numbered from 896, and the number of GPIOs
is 16.
Thanks
Fantastic - it is working now - thank you very much.