Question

我试着编写i2c设备驱动程序，一切都很顺利：

设备检测成功
sysfs类中的设备，也创建了value属性
然后我创建一个hrtimer并启动它
我正在尝试从属性的商店功能发送数据，并且工作正常

但是当我尝试从hrtimer回调函数发送数据时，我的系统会关闭。这是一些代码（我删除了incudes，定义和非重要代码）：

LED-indicator.h

struct timer_job {
        ktime_t period;
        struct hrtimer timer;
        ...
};

struct ledindicator {
        struct i2c_client *client;
        struct device *device;
        struct timer_job job;
        int value;
};

LED-indicator.c

include "led-indicator.h"
static struct ledindicator *li;

// device attribute [value] store function
static ssize_t value_store(struct device *device, struct device_attribute *attr, const char *buffer, size_t count)
{
    int val;
    kstrtoint(buffer, 10, &val);
    li->value = val;
    i2c_smbus_write_byte_data(li->client,  0xBA, 0x02); // this is work fine
    LOG("New value is %d \n", li->value);
    return count;
}

//timer callback, fire each timer_job.period
static enum hrtimer_restart send_next(struct hrtimer * tim) {
    long start = jiffies;
    struct timer_job *job = container_of(tim, struct timer_job, timer);
    i2c_smbus_write_byte_data(li->client, 0xBA, 0x02); // this cause system fault
    hrtimer_forward_now(tim, job->period);
    return HRTIMER_RESTART;
}

//when device is detected I am create sysfs device and init timer. 
enter code here//Also I am crate led_indicator structure and save i2c_client pointer for future use
static int li_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
    int ret = 0;
    li = kmalloc(sizeof(*li), GFP_KERNEL);
    li->client = client;
    li->value = 0;

    ...
    // here creating device and attribute for it
    ...

    hrtimer_init(&(li->job.timer), CLOCK_MONOTONIC, HRTIMER_MODE_REL);

    li->job.timer.function = send_next;
    li->job.period = ktime_set(1, 0); //1 sec
    hrtimer_start(&(li->job.timer), li->job.period, HRTIMER_MODE_REL);

    return ret;
}

有什么问题？

i2c设备驱动程序。尝试发送数据时系统关闭

0 个答案: