GPIO

Access GPIO pins from the Ubuntu Terminal.

Note
  1. This document only for Amlogic 4.9 kernel on VIM1/VIM2/VIM3 and Amlogic 5.4 kernel on VIM4.

Get GPIO Number

Calculation Method

The calculation method of the GPIO array is: Number = Range Base + Pin Index.

  1. Range Base refers to the base value of GPIO ranges.
  2. Pin Index refers to the sorting of the GPIO pins you need to calculate in the corresponding ranges.

Numerical Calculation Example

Amlogic chips usually include two GPIO ranges, AOBUS and Periphs. Examples for each range is provided here for reference.

AOBUS

  1. Get Range Base:
1
2
3
$ cat /sys/kernel/debug/pinctrl/pinctrl@14/gpio-ranges
GPIO ranges handled:
0: aobus-banks GPIOS [501 - 511] PINS [0 - 10]

AOBUS’ Range Base is 501.

  1. Get Pin Index:
1
2
3
4
5
6
7
8
9
10
11
12
13
$ cat /sys/kernel/debug/pinctrl/pinctrl@14/pins
registered pins: 11
pin 0 (GPIOAO_0)  pinctrl@14
pin 1 (GPIOAO_1)  pinctrl@14
pin 2 (GPIOAO_2)  pinctrl@14
pin 3 (GPIOAO_3)  pinctrl@14
pin 4 (GPIOAO_4)  pinctrl@14
pin 5 (GPIOAO_5)  pinctrl@14
pin 6 (GPIOAO_6)  pinctrl@14
pin 7 (GPIOAO_7)  pinctrl@14
pin 8 (GPIOAO_8)  pinctrl@14
pin 9 (GPIOAO_9)  pinctrl@14
pin 10 (GPIO_TEST_N)  pinctrl@14

The pin in front of each GPIO represents the corresponding Pin Index.

Periphs

  1. Get Range Base:
1
2
3
$ cat /sys/kernel/debug/pinctrl/pinctrl@4b0/gpio-ranges 
GPIO ranges handled:
0: periphs-banks GPIOS [401 - 500] PINS [0 - 99]

Periphs’ Range Base is 401.

  1. Get Pin Index:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
$ cat /sys/kernel/debug/pinctrl/pinctrl@4b0/pins
registered pins: 100
pin 0 (GPIOZ_0)  pinctrl@4b0
pin 1 (GPIOZ_1)  pinctrl@4b0
pin 2 (GPIOZ_2)  pinctrl@4b0
pin 3 (GPIOZ_3)  pinctrl@4b0
pin 4 (GPIOZ_4)  pinctrl@4b0
pin 5 (GPIOZ_5)  pinctrl@4b0
pin 6 (GPIOZ_6)  pinctrl@4b0
pin 7 (GPIOZ_7)  pinctrl@4b0
pin 8 (GPIOZ_8)  pinctrl@4b0
pin 9 (GPIOZ_9)  pinctrl@4b0
pin 93 (GPIOX_14)  pinctrl@4b0
pin 94 (GPIOX_15)  pinctrl@4b0
pin 95 (GPIOX_16)  pinctrl@4b0
pin 96 (GPIOX_17)  pinctrl@4b0
pin 97 (GPIOX_18)  pinctrl@4b0
pin 98 (GPIOCLK_0)  pinctrl@4b0
pin 99 (GPIOCLK_1)  pinctrl@4b0
  1. Calculate Number

Take GPIOX_14 as an example here,

GPIOX_14 = Range Base + Pin Index = 401 + 93 = 494.

AOBUS

  1. Get Range Base:
1
2
3
$ cat /sys/kernel/debug/pinctrl/pinctrl@14/gpio-ranges
GPIO ranges handled:
0: aobus-banks GPIOS [501 - 511] PINS [0 - 10]

AOBUS’ Range Base is 501.

  1. Get Pin Index:
1
2
3
4
5
6
7
8
9
10
11
12
13
$ cat /sys/kernel/debug/pinctrl/pinctrl@14/pins
registered pins: 11
pin 0 (GPIOAO_0)  pinctrl@14
pin 1 (GPIOAO_1)  pinctrl@14
pin 2 (GPIOAO_2)  pinctrl@14
pin 3 (GPIOAO_3)  pinctrl@14
pin 4 (GPIOAO_4)  pinctrl@14
pin 5 (GPIOAO_5)  pinctrl@14
pin 6 (GPIOAO_6)  pinctrl@14
pin 7 (GPIOAO_7)  pinctrl@14
pin 8 (GPIOAO_8)  pinctrl@14
pin 9 (GPIOAO_9)  pinctrl@14
pin 10 (GPIO_TEST_N)  pinctrl@14

The pin in front of each GPIO represents the corresponding Pin Index.

Periphs

  1. Get Range Base:
1
2
3
$ cat /sys/kernel/debug/pinctrl/pinctrl@4b0/gpio-ranges 
GPIO ranges handled:
0: periphs-banks GPIOS [401 - 500] PINS [0 - 99]

Periphs的Range Base is 401.

  1. Get Pin Index:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
$ cat /sys/kernel/debug/pinctrl/pinctrl@4b0/pins
registered pins: 100
pin 0 (GPIOZ_0)  pinctrl@4b0
pin 1 (GPIOZ_1)  pinctrl@4b0
pin 2 (GPIOZ_2)  pinctrl@4b0
pin 3 (GPIOZ_3)  pinctrl@4b0
pin 4 (GPIOZ_4)  pinctrl@4b0
pin 5 (GPIOZ_5)  pinctrl@4b0
pin 6 (GPIOZ_6)  pinctrl@4b0
pin 7 (GPIOZ_7)  pinctrl@4b0
pin 8 (GPIOZ_8)  pinctrl@4b0
pin 9 (GPIOZ_9)  pinctrl@4b0
pin 93 (GPIOX_14)  pinctrl@4b0
pin 94 (GPIOX_15)  pinctrl@4b0
pin 95 (GPIOX_16)  pinctrl@4b0
pin 96 (GPIOX_17)  pinctrl@4b0
pin 97 (GPIOX_18)  pinctrl@4b0
pin 98 (GPIOCLK_0)  pinctrl@4b0
pin 99 (GPIOCLK_1)  pinctrl@4b0
  1. Calculate Number

Take GPIOX_14 as an example here,

GPIOX_14 = Range Base + Pin Index = 401 + 93 = 494

AOBUS

  1. Get Range Base:
1
2
3
$ cat /sys/kernel/debug/pinctrl/pinctrl@ff800014/gpio-ranges
GPIO ranges handled:
0: aobus-banks GPIOS [496 - 511] PINS [0 - 15]

AOBUS’ Range Base is 496.

  1. Get Pin Index:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
$ cat /sys/kernel/debug/pinctrl/pinctrl@ff800014/pins
registered pins: 16
pin 0 (GPIOAO_0)  pinctrl@ff800014
pin 1 (GPIOAO_1)  pinctrl@ff800014
pin 2 (GPIOAO_2)  pinctrl@ff800014
pin 3 (GPIOAO_3)  pinctrl@ff800014
pin 4 (GPIOAO_4)  pinctrl@ff800014
pin 5 (GPIOAO_5)  pinctrl@ff800014
pin 6 (GPIOAO_6)  pinctrl@ff800014
pin 7 (GPIOAO_7)  pinctrl@ff800014
pin 8 (GPIOAO_8)  pinctrl@ff800014
pin 9 (GPIOAO_9)  pinctrl@ff800014
pin 10 (GPIOAO_10)  pinctrl@ff800014
pin 11 (GPIOAO_11)  pinctrl@ff800014
pin 12 (GPIOE_0)  pinctrl@ff800014
pin 13 (GPIOE_1)  pinctrl@ff800014
pin 14 (GPIOE_2)  pinctrl@ff800014
pin 15 (GPIO_TEST_N)  pinctrl@ff800014

The pin in front of each GPIO represents the corresponding Pin Index.

Periphs

  1. Get Range Base:
1
2
3
$ cat /sys/kernel/debug/pinctrl/pinctrl@ff634480/gpio-ranges
GPIO ranges handled:
0: periphs-banks GPIOS [410 - 495] PINS [0 - 85]

Periphs’ Range Base is 410.

  1. Get Pin Index:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
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23
$ cat /sys/kernel/debug/pinctrl/pinctrl@ff634480/pins
registered pins: 86
pin 0 (GPIOV_0)  pinctrl@ff634480
pin 1 (GPIOZ_0)  pinctrl@ff634480
pin 2 (GPIOZ_1)  pinctrl@ff634480
pin 3 (GPIOZ_2)  pinctrl@ff634480
pin 4 (GPIOZ_3)  pinctrl@ff634480
pin 5 (GPIOZ_4)  pinctrl@ff634480
pin 6 (GPIOZ_5)  pinctrl@ff634480
pin 7 (GPIOZ_6)  pinctrl@ff634480
pin 8 (GPIOZ_7)  pinctrl@ff634480
pin 9 (GPIOZ_8)  pinctrl@ff634480
...
pin 76 (GPIOX_10)  pinctrl@ff634480
pin 77 (GPIOX_11)  pinctrl@ff634480dd
pin 78 (GPIOX_12)  pinctrl@ff634480
pin 79 (GPIOX_13)  pinctrl@ff634480
pin 80 (GPIOX_14)  pinctrl@ff634480
pin 81 (GPIOX_15)  pinctrl@ff634480
pin 82 (GPIOX_16)  pinctrl@ff634480
pin 83 (GPIOX_17)  pinctrl@ff634480
pin 84 (GPIOX_18)  pinctrl@ff634480
pin 85 (GPIOX_19)  pinctrl@ff634480
  1. Calculate Number

Take GPIOX_10 as an example here,

GPIOX_10 = Range Base + Pin Index = 410 + 76 = 486.

  1. Get Range Base:
1
2
3
$ cat /sys/kernel/debug/pinctrl/fe000000.apb4\:pinctrl\@4000-pinctrl-meson/gpio-ranges
GPIO ranges handled:
0: periphs-banks GPIOS [355 - 511] PINS [0 - 156]
  1. Get Pin Index:
1
2
3
4
5
6
7
8
9
10
11
12
$ cat /sys/kernel/debug/pinctrl/fe000000.apb4\:pinctrl\@4000-pinctrl-meson/pins
registered pins: 157
pin 0 (GPIOB_0)  fe000000.apb4:pinctrl@4000
pin 1 (GPIOB_1)  fe000000.apb4:pinctrl@4000
pin 2 (GPIOB_2)  fe000000.apb4:pinctrl@4000
pin 3 (GPIOB_3)  fe000000.apb4:pinctrl@4000
pin 4 (GPIOB_4)  fe000000.apb4:pinctrl@4000
pin 5 (GPIOB_5)  fe000000.apb4:pinctrl@4000
pin 6 (GPIOB_6)  fe000000.apb4:pinctrl@4000
pin 7 (GPIOB_7)  fe000000.apb4:pinctrl@4000
pin 8 (GPIOB_8)  fe000000.apb4:pinctrl@4000
pin 9 (GPIOB_9)  fe000000.apb4:pinctrl@4000
  1. Calculate Number

Take GPIOT_19 as an examples here.

GPIOT_19 = Range Base + Pin Index = 355 + 110 = 465.

GPIO Usage

When you get the GPIO number, you can follow the steps below to control it. Here will take GPIO number 465 as a example.

  • Export GPIO
1
$ echo 465 | sudo tee /sys/class/gpio/export
  • Set GPIO direction

You can set the direction input or output.

1
2
$ echo out | sudo tee /sys/class/gpio/gpio465/direction # Set GPIO output
$ echo in | sudo tee /sys/class/gpio/gpio465/direction # Set GPIO input
  • Set or get GPIO value
1
2
3
$ echo 1 | sudo tee /sys/class/gpio/gpio465/value # Set GPIO output high
$ echo 0 | sudo tee /sys/class/gpio/gpio465/value # Set GPIO output low
$ cat /sys/class/gpio/gpio465/value # Get GPIO input value
  • Unexport GPIO
1
$ echo 465 | sudo tee /sys/class/gpio/unexport

Unexport to release the GPIO.