automatically bind a device to a specific driver

Question

I would like to bind a hid device to a specific driver.

Unfortunately hid-generic somehow "steals" the binding when the device is reconnected.

I know i can unbind and bind the device by hand this way:

# echo ... > /sys/bus/hid/drivers/hid-generic/unbind 
# echo ... > /sys/bus/hid/drivers/customdriver/bind

But isn't there something like a priority for drivers to automatically bin a device to a driver?

Thank you in advance!

Answer 1

I found two ways to automatically bind a device to my driver

• Adding the device to the hid_have_special_driver struct in hid-core.c.

  The struct looks somthing like that:

  static const struct hid_device_id hid_have_special_driver[] = {
  #if IS_ENABLED(CONFIG_HID_A4TECH)
      { HID_USB_DEVICE(USB_VENDOR_ID_A4TECH, USB_DEVICE_ID_A4TECH_WCP32PU) },
      { HID_USB_DEVICE(USB_VENDOR_ID_A4TECH, USB_DEVICE_ID_A4TECH_X5_005D) },
      { HID_USB_DEVICE(USB_VENDOR_ID_A4TECH, USB_DEVICE_ID_A4TECH_RP_649) },
  #endif
      //...
      {}
  }
  

  This is how it is normally done, I haven't tried it yet. You have to recompile hid-core.c (hid.ko).

• Using the bind and unbind functionality inside an udev-rule.

  Add a new rule to /etc/udev/rules.d/ (e.g. 99-mydriver.rules) which automatically unbinds the device from hid-generic and binds it to your driver

  Under Arch Linux x86_64:

  ACTION=="bind", KERNELS=="0005:<VENDOR_ID>:<PRODUCT_ID>.*", SUBSYSTEMS=="hid", DRIVERS=="hid-generic", \
  RUN+="/bin/bash -c 'echo $kernel > /sys/bus/hid/drivers/$driver/unbind'", \
  RUN+="/bin/bash -c 'echo $kernel > /sys/bus/hid/drivers/<MY_DRIVER>/bind'" 
  

  Under Raspbian Stretch the following works for me

  ACTION=="add", KERNEL=="0005:<VENDOR_ID>:<PRODUCT_ID>.*", SUBSYSTEM=="hid", DRIVER=="hid-generic", \
  RUN+="/bin/bash -c 'echo $kernel > /sys/bus/hid/drivers/hid-generic/unbind'", \
  RUN+="/bin/bash -c 'echo $kernel > /sys/bus/hid/drivers/<MY_DRIVER>/bind'" 
  

  Replace <VENDOR_ID>, <PRODUCT_ID> and <MY_DRIVER> as needed

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Further Information: http://0x0001.de/linux-driver-loading-registration-and-binding/