SMI330 Linux IIO Driver

A comprehensive Linux Industrial I/O (IIO) driver for the Bosch SMI330 6-axis Inertial Measurement Unit (IMU).

Table of Contents

• Introduction
• Features
• Hardware Specifications
• Supported Platforms
• Building and Installation
• Device Tree Configuration
• Usage
• Troubleshooting
• Documentation
• Architecture
• License

Introduction

The SMI330 is a highly integrated, low-power inertial measurement unit (IMU) that combines precise acceleration and angular rate (gyroscopic) measurements with intelligent on-chip motion-triggered interrupt features. This Linux IIO driver provides a standardized interface for accessing all sensor capabilities through the Industrial I/O subsystem.

Features

Core Functionality

• 3-axis accelerometer with configurable ranges: ±2g, ±4g, ±8g, ±16g
• 3-axis gyroscope with configurable ranges: ±125°/s, ±250°/s, ±500°/s
• Temperature sensor with operating range: -40°C to +125°C
• Hardware FIFO with configurable watermark levels
• Multiple communication interfaces: I2C and SPI

Advanced Features

• Motion detection and no-motion detection
• Tilt detection
• Self-calibration (Component Re-Trim)
• Self-test functionality
• Soft reset capability
• Auto-operation mode with power management
• Configurable interrupt pins (INT1, INT2)
• Open-drain and push-pull interrupt configuration
• Wake-up source support for system suspend/resume

Driver Features

• Standard Linux IIO interface
• Sysfs attribute support
• Device tree integration
• Power management support with wake-up capability
• Multi-instance support
• Comprehensive error handling

Hardware Specifications

Parameter	Specification
Supply Voltage	1.71V - 3.6V
Interface	I2C (up to 400kHz) / SPI (up to 10MHz)
Resolution	16-bit ADC
Operating Temperature	-40°C to +125°C
Current Consumption	Low power modes available

Supported Platforms

Tested Kernels

• Linux 6.6.y (Raspberry Pi)
• Linux 6.12.y (Raspberry Pi)

Integration Guide

1. Clone: git clone https://github.com/boschmemssolutions/SMI330-Linux-Driver-IIO.git
2. Copy: cp -r SMI330-Linux-Driver-IIO/drivers/iio/imu/smi330 linux/drivers/iio/imu/
3. Kconfig: add source "drivers/iio/imu/smi330/Kconfig"
4. Makefile: add obj-$(CONFIG_SMI330) += smi330/ (plus I2C/SPI objects)
5. Enable: CONFIG_SMI330[,_I2C,_SPI] + select interrupt mapping
6. Add DT node / overlay (compatible = "bosch,smi330")
7. Build + deploy: make Image modules dtbs then install & boot; verify via dmesg | grep smi330 & ls /sys/bus/iio/devices

See Integration Guide for a more comprehensive documentation.

Documentation

• Online Documentation
• Website
• Sysfs Interface

Architecture

                    User Space Applications
                           |
    ┌─────────────────────────────────────────────────────┐
    │                 IIO Subsystem                       │
    ├─────────────────────────────────────────────────────┤
    │  sysfs interface  │  chardev  │  buffer interface   │
    └─────────────────────────────────────────────────────┘
                           |
    ┌─────────────────────────────────────────────────────┐
    │               SMI330 IIO Driver                     │
    │  ┌─────────────┐ ┌─────────────┐ ┌─────────────┐    │
    │  │ smi330_core │ │ smi330_i2c  │ │ smi330_spi  │    │
    │  └─────────────┘ └─────────────┘ └─────────────┘    │
    └─────────────────────────────────────────────────────┘
                           |
    ┌─────────────────────────────────────────────────────┐
    │           Hardware Abstraction Layer                │
    │        I2C Subsystem    │    SPI Subsystem          │
    └─────────────────────────────────────────────────────┘
                           |
                    SMI330 Hardware

License

See LICENSE for detailed terms.