====== I2C ======

===== Introduction =====

This page introduces the usage of I2C bus on [[products:sbc:common:applications:gpio:40pin-header|40-Pin Header]].

===== I2C Information =====

|           ^  I2C     ^  PIN      ^  GPIO Name  ^  DT Overlays Node  ^  Bus Number  ^  Device Node  ^
^  VIM1/2   |  I2C A   |  22(SCL)  |  GPIODV_25  |  i2c0              |  0           |  /dev/i2c-0   |
| :::       | :::      |  23(SDA)  |  GPIODV_24  | :::                | :::          | :::           |
| :::       |  I2C B   |  25(SCL)  |  GPIODV_27  |  -                 |  1           |  /dev/i2c-1   |
| :::       | :::      |  26(SDA)  |  GPIODV_26  | :::                | :::          | :::           |
^  VIM3/3L  |  I2CM 3  |  22(SCL)  |  GPIOA_15   |  i2c3              |  3           |  /dev/i2c-3   |
| :::       | :::      |  23(SDA)  |  GPIOA_14   | :::                | :::          | :::           |
| :::       |  I2C AO  |  25(SCL)  |  GPIOAO_2   |  -                 |  4           |  /dev/i2c-4   |
| :::       | :::      |  26(SDA)  |  GPIOAO_3   | :::                | :::          | :::           |
^  VIM4     |  I2CM F  |  22(SCL)  |  GPIOY_17   |  i2cm_f            |  5           |  /dev/i2c-5   |
| :::       | :::      |  23(SDA)  |  GPIOY_18   | :::                | :::          | :::           |
| :::       |  I2CM A  |  25(SCL)  |  GPIOT_20   |  i2cm_a            |  0           |  /dev/i2c-0   |
| :::       | :::      |  26(SDA)  |  GPIOT_21   | :::                | :::          | :::           |
^  VIM1S    |  I2CM B  |  22(SCL)  |  GPIOD_7    |  -                 |  1           |  /dev/i2c-1   |
| :::       | :::      |  23(SDA)  |  GPIOD_6    | :::                | :::          | :::           |
| :::       |  I2CM E  |  25(SCL)  |  GPIOZ_11   |  i2cm_e            |  4           |  /dev/i2c-4   |
| :::       | :::      |  26(SDA)  |  GPIOZ_12   | :::                | :::          | :::           |

===== Enable I2C =====

In order to use the I2C, you need to enable the I2C function via [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]].

<tabbox VIM1/2/3/3L/Edge1>

Edit ''/boot/env.txt'' to add the i2c node to ''overlays'' node if it doesn't exist.

Take VIM3 as an example to enable ''I2CM 3'', you need to add ''i2c3'' node to ''overlays'' node if it doesn't exist.

```shell
overlays=uart4 pwm_ao_a pwm_f i2c3
```

After reboot, you will see the I2C device node.

```shell
$ ls /dev/i2c-3
/dev/i2c-3
```

<tabbox VIM3 with 5.15 kernel>

Edit ''/boot/dtb/amlogic/kvim3.dtb.overlay.env'' to add i2c node to ''fdt_overlays'' node if it doesn't exist.


e.g. To enable ''I2CM 3'', you need to add ''i2c3'' to node ''fdt_overlays'' if it doesn't exist.

```shell
fdt_overlays=i2c3

```

After reboot, you will see the I2C device node.

<tabbox VIM3L with 5.15 kernel>

Edit ''/boot/dtb/amlogic/kvim3l.dtb.overlay.env'' to add i2c node to ''fdt_overlays'' node if it doesn't exist.


e.g. To enable ''I2CM 3'', you need to add ''i2c3'' to node ''fdt_overlays'' if it doesn't exist.

```shell
fdt_overlays=i2c3

```

After reboot, you will see the I2C device node.

<tabbox VIM4>

Edit ''/boot/dtb/amlogic/kvim4.dtb.overlay.env'' to add i2c node to ''fdt_overlays'' node if it doesn't exist.


e.g. To enable ''I2CM A'', you need to add ''i2cm_a'' to node ''fdt_overlays'' if it doesn't exist.

```shell
fdt_overlays=i2cm_a

```

After reboot, you will see the I2C device node.

```shell
$ ls /dev/i2c-0
/dev/i2c-0
```

<tabbox VIM1S>

Edit ''/boot/dtb/amlogic/kvim1s.dtb.overlay.env'' to add i2c node to ''fdt_overlays'' node if it doesn't exist.


e.g. To enable ''I2CM E'', you need to add ''i2cm_e'' to node ''fdt_overlays'' if it doesn't exist.

```shell
fdt_overlays=i2cm_e

```

After reboot, you will see the I2C device node.

```shell
$ ls /dev/i2c-4
/dev/i2c-4
```

</tabbox>

===== I2C Usage =====

Please check the [[https://manpages.ubuntu.com/manpages/jammy/en/man8/i2cdetect.8.html|I2C Usage]].


===== Disable I2C to Use GPIO =====

If you want to use normal GPIO instead of I2C, you can remove the I2C node in [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]].