# Map an ACPI device to a QUP instance

The GPIO mapping for a QUP instance depends on the configured mode.
Each Advanced Configuration and Power Interface (ACPI) device maps to
a QUP instance.

Use the following examples and the lane-to-function table to identify
which GPIO lines carry each signal before you enable an instance.

- I^2^C example

    ACPI `I2C1` maps to `QUP_1`, which has GPIO mappings from 4 to 5.

    - `GPIO_4` is L0 (serial data line, SDA).
    - `GPIO_5` is L1 (serial clock line, SCL).
- SPI example

    ACPI `SP22` maps to `QUP_22`, which has GPIO mappings from 88 to 91.

    - `GPIO_88` is L0 (MISO).
    - `GPIO_89` is L1 (MOSI).
    - `GPIO_90` is L2 (SCLK).
    - `GPIO_91` is L3 (CS0).
- UART example

    ACPI `UAR2` maps to `QUP_2`, which has GPIO mappings from 8 to 11.

    - `GPIO_8` is L0 (UART CTS).
    - `GPIO_9` is L1 (UART RFR).
    - `GPIO_10` is L2 (UART Tx).
    - `GPIO_11` is L3 (UART Rx).

## Map QUP lane-to-function

The following table lists the QUP lane-to-function mapping for each
protocol.

| Protocol | L0 | L1 | L2 | L3 | L4 | L5 |
| --- | --- | --- | --- | --- | --- | --- |
| UART | CTS | RFR | Tx | Rx | — | — |
| HS UART | CTS | RFR | Tx | Rx | — | — |
| I^2^C | SDA | SCL | — | — | — | — |
| I^3^C | SDA | SCL | — | — | — | — |
| SPI | MISO | MOSI | SCLK | `CS_0` | `CS_1` | `CS_2` |

## Related

- [QUP serial engine reference](https://docs.qualcomm.com/doc/80-A0399-8/topic/qup-serial-engine-reference.html)
- [Enable the I2C interface](https://docs.qualcomm.com/doc/80-A0399-8/topic/enable-i2c-interface.html)
- [Enable the SPI interface](https://docs.qualcomm.com/doc/80-A0399-8/topic/enable-spi-interface.html)

Last Published: Sep 17, 2026

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