Steward

分享是一種喜悅、更是一種幸福

驅動程式 - Linux Device Driver (LDD) - 使用範例 - C/C++ (Debian) - Hardware Monitoring

---

main.c

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/slab.h>

struct simple_data {
    int temp;
};

static umode_t simple_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel)
{
    if (type == hwmon_temp && attr == hwmon_temp_input) {
        return 0444;
    }

    return 0;
}

static int simple_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val)
{
    struct simple_data *d = dev_get_drvdata(dev);

    if (type == hwmon_temp && attr == hwmon_temp_input) {
        *val = d->temp;
        return 0;
    }

    return -EOPNOTSUPP;
}

static const struct hwmon_ops simple_hwmon_ops = {
    .is_visible = simple_is_visible,
    .read = simple_read,
};

static const struct hwmon_channel_info *simple_info[] = {
    HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
    NULL
};

static const struct hwmon_chip_info simple_chip_info = {
    .ops = &simple_hwmon_ops,
    .info = simple_info,
};

static int simple_probe(struct platform_device *pdev)
{
    struct simple_data *d = NULL;
    struct device *hwmon_dev = NULL;

    d = devm_kzalloc(&pdev->dev, sizeof(*d), GFP_KERNEL);
    d->temp = 9999;
    dev_set_drvdata(&pdev->dev, d);

    hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, "simple_hwmon", d, &simple_chip_info, NULL);
    return 0;
}

static int simple_remove(struct platform_device *pdev)
{
    return 0;
}

static struct platform_driver simple_driver = {
    .probe  = simple_probe,
    .remove = simple_remove,
    .driver = {
        .name = "simple_hwmon",
    },
};

static struct platform_device *simple_pdev = NULL;

static int __init simple_init(void)
{
    simple_pdev = platform_device_register_simple("simple_hwmon", -1, NULL, 0);
    return platform_driver_register(&simple_driver);
}

static void __exit simple_exit(void)
{
    platform_driver_unregister(&simple_driver);
    platform_device_unregister(simple_pdev);
}

module_init(simple_init);
module_exit(simple_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steward");
MODULE_DESCRIPTION("Simple hwmon driver");

完成

$ cat /sys/class/hwmon/hwmon1/name 
    simple_hwmon

$ cat /sys/class/hwmon/hwmon1/temp1_input 
    9999