Re: Interacting with a input kernel driver from user space

[Nuno Santos <nsantos@edigma.com>]

Hi,

I have defined my first attribute in the following way:

static ssize_t usbtouchscreen_update_sensibility(struct device *dev,
                                         struct device_attribute *attr,
                                         const char *buf, size_t count)
{

     printk(KERN_INFO "update sensibility called");

     return 0;
}

static DEVICE_ATTR(sensibility, 0664, NULL, 
usbtouchscreen_update_sensibility);

static struct attribute *usbtouchscreen_attrs[] = {
&dev_attr_sensibility.attr,
         NULL
};

static const struct attribute_group usbtouchscreen_attr_group = {
         .attrs = usbtouchscreen_attrs,
};

In the probe function I have added:

if (sysfs_create_group(&intf->dev.kobj, &usbtouchscreen_attr_group))
         goto out_unregister_input;


Then I tried to write on the attribute in the following way:

nsantos@NS-PC:~/workspaces/linux-kernel-driver$ echo 45 > 
/sys/class/input/input7/sensibility
bash: /sys/class/input/input7/sensibility: No such file or directory

After digging a bit under /sys/class/input/input7 i found that the sub 
directory device add sensibilty listed so I tried the following:

nsantos@NS-PC:~/workspaces/workspace-mtt/linux-kernel-driver$ sudo echo 
45 > /sys/class/input/input7/device/sensibility
bash: /sys/class/input/input7/device/sensibility: Permission denied

With no success again...

Am I doing something terribly wrong?

Thanks in advance,

Regards,

Nuno