How to use GPIO RK3576

Configuration

The RK3576 bank/bit notation for GPIOs must be formed as "GPIO<GPIO_bank>_<gpio_bit>" 

The numeric value of GPIO is calculated as follows:

32 x (gpio_bank) + gpio_bit<br/> 

gpio_bit : A0～A7 0-7 B0～B7 8-15 C0～C7 16-23 D0～D7 24-31

E.g. GPIO3_A0 becomes 96

 

AOM-3841

GPIO Number	GPIO formed	Numeric Representation
GPIO3	GPIO0_B0	8
GPIO4	GPIO4_C5	149

Test

Here we take GPIO3 of AOM-3841 as an example.

Export GPIO then you can use control GPIO from userr space through sysfs

Export GPIO3

# echo 8 > /sys/class/gpio/export

Set GPIO direction to in/out

# echo "out" > /sys/class/gpio/gpio8/direction

Set GPIO value 0/1 if GPIO pin define is output

#  echo 1 > /sys/class/gpio/gpio8/value

Used as IRQ signal

Note:You have to configure GPIO to input

#  echo "rising" > /sys/class/gpio/gpio8/edge

• rising: Trigger on rising edge
• falling: Trigger on falling edge
• both: Trigger on both edges
• none: Disable interrupt on both edges

Unexport GPIO3

# echo 8 > /sys/class/gpio/unexport

Test

GPIO3 and GPIO4 of AOM-3841 are taken as an example:

• Connect GPIO3 and GPIO4
• Export GPIO3 and GPIO4

# echo 8 > /sys/class/gpio/export
# echo 149 > /sys/class/gpio/export

• Set GPIO3 to output

# echo "out" > /sys/class/gpio/gpio8/direction

• Set GPIO4 to input

# echo "in" > /sys/class/gpio/gpio149/direction

• Change GPIO3 to 1 and read GPIO4 value

# echo 1 > /sys/class/gpio/gpio8/value
# cat /sys/class/gpio/gpio149/value 
1

• Change GPIO3 to 0 and read GPIO4 value

# echo 0 > /sys/class/gpio/gpio8/value
# cat /sys/class/gpio/gpio149/value 
0