Hello,
I am writing a simple driver with an irq for Dragonboard410c. Kernel was built from 2016.03 branch.
I am using gpio_request, gpio_direction_input, gpio_to_irq, and request_irq in my code, but I’ve got the following errors at run-time.
Unknown symbol gpiod_to_irq (err 0)
Unknown symbol gpio_free (err 0)
Unknown symbol gpiod_direction_input (err 0)
Unknown symbol gpio_to_desc (err 0)
Unknown symbol gpio_request (error 0)
I used GPIO_C (13) in my code.
I need your help.
-Hyoung.
Hi @hham,
I am not so sure only with from the error message but are you trying to write a new kernel driver using GPIO?
I am not good at writing kernel driver either but I would start from including “linux/gpio/consumer.h” the source code and turn on GPIOLIB in the kernel config option.
Would this help?
Hi, Akira.
Thank you for your quick answer.
Yes, I am writing a simple device driver using GPIO interrupt. Including “linux/gpio/consumer.h” was not helpful. The following configs from kernel config(distro.config) are included already.
CONFIG_ARCH_WANT_OPTIONAL_GPIOLIB=y
CONFIG_ARCH_REQUIRE_GPIOLIB=y
CONFIG_GPIOLIB=y
However, it doesn’t help. Any other clue?
The last kernel module I wrote that used GPIOs and interrupts required the following includes:
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <asm/uaccess.h>
#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
This was on a different system, however linux/gpio.h is what defines gpio_request and gpio_free, so it’s a start.
Is MODULE_LICENSE defined? Maybe you can share your code?
Hi suicidaleggroll and vchong,
Thank you for your answer. Yes, MODULE_LICENSE is defined, and it has been fixed since I added all the include files.
Now I have another issue, gpio_request failure. I am using GPIO_C(13). When I called gpio_request, I get -16(EBUSY). What can I do to make GPIO_C usable?
I think it’s being used as an spi pin as specified in the DT [1].
If true, you’ll have to change the DT to configure it as gpio instead and rebuild.
