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wchen50's avatar
wchen50
Icon for New Contributor rankNew Contributor
7 years ago

Altera DE0-Nano gpio

In my testing, I want to access the fpga gpio. I can use set the fpga gpio pin from user space (open /dev/mem, then use mmap, etc). However I cannot set the fpga from kernel space. In my kernel code...
FawazJ_Altera's avatar
FawazJ_Altera
Icon for Frequent Contributor rankFrequent Contributor
7 years ago

Hello,

I found this useful link:

https://lwn.net/Articles/532714/

Please refer to it, the summary of accessing GPIO:

1- include the driver:

#include <linux/gpio.h>

2- GPIOs must be allocated before use:

int gpio_request(unsigned int gpio, const char *label);

3- And GPIO can be returned to the system with:

void gpio_free(unsigned int gpio);

4- Configure GPIO as Input/Output:

int gpio_direction_input(unsigned int gpio);

int gpio_direction_output(unsigned int gpio, int value);

5- Run GPIO:

int gpio_get_value(unsigned int gpio);

void gpio_set_value(unsigned int gpio, int value);

Hope this might help.

Thanks