I have an ARM based board with usb interface. To use the usb interface I use the following commands:
insmod usbserial.ko vendor=0x... product=0x...
> mknod /dev/ttyUSB0 c 188 0
If I try to use the device with echo or cat I get the error "No such device". Could you help me?
Bye
vendor=0x... product=0x...
"modprobe", which should load all dependencies as well. Eg: usbserial probably needs the USB core, USB Hub, OHCI/EHCI .... modules etc. Also check the log files (dmesg, syslog etc) to see if those modules were successfully loaded. Cheers Janaka
vendor=0x... product=0x...
With modinfo I see that the module usbserial doesn't have dependency. In this case insmod and modprobe do the same work?
modinfo drivers/usb/serial/usbserial.ko filename: drivers/usb/serial/usbserial.ko author: Greg Kroah-Hartman, snipped-for-privacy@kroah.com,
Bye
usbserial.ko vendor=0x... product=0x...
That doesn't sound right! You may have the core Usb modules ..etc compiled in to the kernel or a strange setup. The reason I say the above is, USB is a reasonably complex bus with multiple levels of control. At the highest level there must be a root hub. Some boards have a dedicated chip for this, and some others have it on their processor (an SOC design). To enable and operate that you need a kernel driver/module. Next level down you may (or may not) have a USB hub, which increases the number of USB devices that can be connected to the Root hub and takes care of power needs. This may have further control/driver modules. Next level down in the tree structure will be your device driver for the USB serial product (Most likely a CDC [communications device] or a HID [ Human interface Device]). There may be more layers depending on the complexity of the HW setup.
The other thing could be that modinfo may not show all the dependencies if a SOC controlling code is in a one big driver. If none of the above helps, you can try dividing the problem and to solve it:
vendor=0x... product=0x...
You do not have the device driver at all. usbserial is a module for the common parts of USB serial drivers.
As an example, I plugged in a simple USB serial cable, Aten International Co Ltd UC-232A, vendor ID 0x557 and product ID 0x2008.
It needs the modules:
pl2303 usbserial, used by pl2303
The command
modprobe pl2303
loads both modules.
HTH
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