zephyr-device-drivers

Zephyr Device Drivers

Expert guidance on Zephyr's device driver model, creating custom drivers, using existing driver APIs, and implementing bus-specific device patterns.

Table of Contents

1. Quick Start
2. Core Concepts
3. Using Existing Drivers
4. Creating Custom Drivers
5. Bus-Specific Patterns
6. Sensor Subsystem
7. Testing Drivers
8. Troubleshooting

---

Quick Start

Using an Existing Driver

#include <zephyr/device.h>
#include <zephyr/drivers/gpio.h>

/* Get device from devicetree */
const struct device *gpio_dev = DEVICE_DT_GET(DT_NODELABEL(gpio0));

/* Check device is ready */
if (!device_is_ready(gpio_dev)) {
    printk("GPIO device not ready\n");
    return -ENODEV;
}

/* Use driver API */
gpio_pin_configure(gpio_dev, 13, GPIO_OUTPUT_ACTIVE);
gpio_pin_set(gpio_dev, 13, 1);

Minimal Custom Driver Structure

#define DT_DRV_COMPAT vendor_mydevice

struct mydevice_config {
    /* Immutable config from devicetree */
};

struct mydevice_data {
    /* Runtime mutable state */
};

static int mydevice_init(const struct device *dev)
{
    return 0;
}

#define MYDEVICE_INIT(inst)                                     \
    static struct mydevice_data mydevice_data_##inst;           \
    static const struct mydevice_config mydevice_config_##inst; \
    DEVICE_DT_INST_DEFINE(inst, mydevice_init, NULL,            \
                          &mydevice_data_##inst,                \
                          &mydevice_config_##inst,              \
                          POST_KERNEL,                          \
                          CONFIG_KERNEL_INIT_PRIORITY_DEVICE,   \
                          NULL);

DT_INST_FOREACH_STATUS_OKAY(MYDEVICE_INIT)

---

Core Concepts

Device Model Overview

Zephyr's device model provides:

• Static device definitions at compile time via devicetree
• Lazy initialization based on initialization levels
• API abstraction through driver API structures
• Power management integration