usb_register_dev 沒有在/dev底下新增裝置節點

Chip Platform Rockchip
1

Dear Firefly:
I encountered a problem for USB drivers that usb_register_dev do not create device under /dev
Here is the code

static char *flv_devnode(struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, “%s”, dev_name(dev));
}

static struct usb_class_driver flv_class_driver = {
.name = “flv%d”,
.fops = &flv_fops_nop,
.devnode = flv_devnode,
.minor_base = FLV_MINOR_BASE,
};

Static int flv_probe(struct usb_interface dev_if, …)
{

    usb_set_intfdata(dev_if, &flv_class_driver);

    retval = usb_register_dev(dev_if, &flv_class_driver);
    if (retval != 0) {
            /* something prevented us from registering this driver */
            printk(KERN_INFO "%s() unable to get a minor for this device.\n", __func__);
            usb_set_intfdata(dev_if, NULL);
            goto _safe_exit;
    }

}

The function usb_register_dev should create file not only under /sys/class/usbmisc/flv0, but under /dev/flv0.
However, I cannot see the device file under /dev.

I also refer to snd_register_device(), which successfully create device under /dev/snd, but can not find the key place.

Could you give me some suggestions? Thank you very much.

Thanks,

2

Android init process will ignore usb uevent, so please modified ~/$proj/system/core/init/device.c

…
if (!strncmp(uevent->subsystem, “usb”, 3)) {
if (!strcmp(uevent->subsystem, “usb”)) {
if (uevent->device_name) {
/*
* create device node provided by kernel if present
* see drivers/base/core.c
*/
char p = devpath;
snprintf(devpath, sizeof(devpath), “/dev/%s”, uevent->device_name);
/ skip leading /dev/ /
p += 5;
/ build directories */
while (*p) {
if (*p == ‘/’) {
*p = 0;
make_dir(devpath, 0755);
p = ‘/’;
}
p++;
}
}
else {
/ This imitates the file system that would be created
* if we were using devfs instead.
* Minors are broken up into groups of 128, starting at “001”
/
int bus_id = uevent->minor / 128 + 1;
int device_id = uevent->minor % 128 + 1;
/ build directories /
make_dir(“/dev/bus”, 0755);
make_dir(“/dev/bus/usb”, 0755);
snprintf(devpath, sizeof(devpath), “/dev/bus/usb/%03d”, bus_id);
make_dir(devpath, 0755);
snprintf(devpath, sizeof(devpath), “/dev/bus/usb/%03d/%03d”, bus_id, device_id);
}
} else {
/ ignore other USB events */
if(!strncmp(name, “flv”,3)){
base = “/dev/”;
}
else
return;
}
…

3

{:3_48:}nice

4

thx.{:4_158:}