// LINUX DEVICE DRIVERS

Linux Kernel Driver
Specialists

We write production Linux kernel drivers for custom hardware peripherals — I²C, SPI, UART, USB, PCIe, V4L2, ALSA, and custom FPGA interfaces on any Linux platform.

View Our Work

30+

Driver Projects

6.x

Kernel Expertise

All

Bus Types

DKMS

Out-of-Tree

Writing a Linux device driver that works reliably in production — through kernel upgrades, concurrent access, hardware glitches, and race conditions — requires deep knowledge of the Linux kernel internals, memory barriers, DMA coherency, and the specific subsystem you are working in.

Codewave Labs has written drivers that ship in production devices: custom camera ISP drivers in the V4L2 framework, industrial sensor drivers in the IIO subsystem, audio codec drivers in ALSA, high-speed USB device drivers, PCIe endpoint drivers for FPGA bridges, and platform drivers for custom mixed-signal peripherals.

We write drivers that are clean enough to submit upstream (and we do submit them when appropriate), that handle error cases gracefully, and that don't leak memory or leave hardware in undefined states on module removal.

// WHAT WE DELIVER

Our Capabilities

I²C / SPI / UART Drivers

Platform drivers, regmap-based register access, interrupt handling, DMA transfers, power management (runtime PM), and device tree bindings.

USB Device & Host Drivers

USB gadget drivers (CDC-ACM, CDC-ECM, HID, bulk), USB host drivers (custom class, vendor-specific), and composite device configurations.

PCIe / FPGA Drivers

PCIe endpoint and root complex drivers, FPGA bridge interfaces, memory-mapped register access, MSI/MSI-X interrupt handling, and IOMMU/DMA.

V4L2 Camera & Media Drivers

ISP drivers, MIPI-CSI2 receivers, video capture pipelines, V4L2 subdevice architecture, media controller framework, and libcamera integration.

ALSA Audio Drivers

Platform and codec ASoC drivers, DAPM widget configuration, PCM interface, DMA audio transfers, Jack detection, and multi-card configurations.

IIO Sensor Drivers

Industrial I/O subsystem drivers for ADCs, DACs, IMUs, temperature sensors, pressure sensors, and current/voltage monitors with triggered buffering.

// TECHNOLOGIES & PLATFORMS

Platforms We Master

Linux 5.x / 6.x Kernel

Up-to-date kernel driver development following current coding style and API conventions

I²C Subsystem

i2c_driver, i2c_client, smbus, regmap-i2c, interrupt handling, clock stretching

SPI Subsystem

spi_driver, DMA SPI, CS GPIO, mode configuration, multi-device SPI bus management

USB Subsystem

USB gadget (configfs), USB host (usbcore), libusb integration, DFU gadget

PCIe Subsystem

pci_driver, MMIO, MSI/MSI-X, DMA API, iommu_group, endpoint framework

V4L2 / Media

v4l2_subdev, video_device, media_entity, MIPI-CSI2, ISP pipeline, libcamera

FPGA Subsystem

fpga_manager, fpga_bridge, fpga_region, partial reconfiguration, MMIO bridge drivers

DKMS Out-of-Tree

Kernel version-independent out-of-tree modules with DKMS for long-term maintenance

// HOW WE ENGAGE

Our Approach

Hardware Analysis

Study your hardware datasheet, register map, timing diagrams, and interrupt architecture before writing any code.

Subsystem Selection

Map your hardware to the correct Linux kernel subsystem (IIO, V4L2, ALSA, etc.) for maximum compatibility and userspace support.

Driver Implementation

Write the driver with proper error handling, power management, device tree bindings, and comprehensive kernel doc comments.

Testing & Upstreaming

Test with fault injection, concurrent access, module load/unload cycles, and optionally submit to the appropriate kernel mailing list.

// COMMON QUESTIONS

Frequently Asked Questions

Both. For product-specific drivers, out-of-tree with DKMS is usually the right choice. For generic hardware (sensors, codecs, etc.), we write drivers clean enough to submit to the Linux kernel and handle the review process. Upstreamed drivers are maintained by the community — better long-term.

Yes. This is a common request. We diff the kernel API changes between versions, update the driver to use current APIs, and verify functionality. We also add device tree bindings if the original driver used platform data.

We test with: (1) normal operation across all supported hardware, (2) error injection (I2C NACK, SPI timeout, USB disconnect), (3) concurrent access from multiple userspace processes, (4) rapid module load/unload, (5) PM suspend/resume cycles. For PCIe drivers we also test with surprise removal.

Yes. We write V4L2 subdevice drivers for MIPI-CSI2 cameras following the media controller framework. We handle sensor register programming, auto-exposure/gain control, format negotiation, and integration with the SoC's ISP or MIPI receiver bridge.

A device tree binding defines how your hardware is described in the device tree — register addresses, interrupts, clocks, GPIO assignments, and properties. Yes, every in-tree Linux driver must have a documented binding schema (YAML). We write and validate these as part of every driver engagement.

// GET STARTED

Ready to Start?

Tell us about your project — hardware platform, current challenges, timeline, and goals. First consultation is always free. We typically respond within 1 business day.

hello@codewavelabs.ca

Response time

Within 1 business day

Location

Canada 🇨🇦 — serving clients worldwide

Linux Kernel DriverSpecialists