How to access /dev/mem?

Question

linux

Using the pigpio library, there is no way to access the GPIO two I2C ports through /dev/mem without root. I can access /dev/gpiomem but there is no source for Tinker Board to recompile it, what can I do? Everything works with root: /dev/mem access test: /dev/gpiomem access: No access after group modification and write permission for everyone:

Answer 1

Add the relevant user to the kmem group

Answer 2

How to write to I2C port of Tinker Board for imu sensors without using /dev/mem:

#include <sys/ioctl.h>
#include <unistd.h>

#define I2C_SLAVE	0x0703

fd_1 = open("/dev/i2c-1", O_RDWR /*чтение и запись*/);

ioctl( fd_1, I2C_SLAVE, _address /* Адресс устройства*/ );

bool BNO055::write8(bno055_reg_t reg, uint8_t value /*регистр устройства, данные*/)
{
  uint8_t buf[2] = { reg, value };

  if(write( fd_1, &buf, 2) != 2) {
      qDebug()<<"Ошибка записи I2C в регистр: "<<reg;
      return -1;
  }
  return true;
}