Termux-usb

-l               list available devices
-r               show permission request dialog if not already granted
-e command       execute the specified command with a file descriptor
                 referring to the device as its argument

Android doesn't allow direct access to usb devices, you need to request a file descriptor for the device from the Java API instead. This means that Linux usb software will need to be modified to work within Termux.

Here is a sample project to get started:

Make sure you have the Termux:API application installed. Set up the necessary packages within Termux.

pkg install termux-api libusb clang

Enable OTG (host) mode and insert a usb device. Wait for it to be recognised and verify it using the API:

termux-usb -l

Let's assume the device is /dev/bus/usb/001/002. Ask for permission to access it:

termux-usb -r /dev/bus/usb/001/002

Try using it from libusb. Save this sample code as usbtest.c: (download)

#include <stdio.h>
#include <assert.h>
#include <libusb-1.0/libusb.h>

int main(int argc, char **argv) {
    libusb_context *context;
    libusb_device_handle *handle;
    libusb_device *device;
    struct libusb_device_descriptor desc;
    unsigned char buffer[256];
    int fd;
    assert((argc > 1) && (sscanf(argv[1], "%d", &fd) == 1));
    libusb_set_option(NULL, LIBUSB_OPTION_NO_DEVICE_DISCOVERY);
    assert(!libusb_init(&context));
    assert(!libusb_wrap_sys_device(context, (intptr_t) fd, &handle));
    device = libusb_get_device(handle);
    assert(!libusb_get_device_descriptor(device, &desc));
    printf("Vendor ID: %04x\n", desc.idVendor);
    printf("Product ID: %04x\n", desc.idProduct);
    assert(libusb_get_string_descriptor_ascii(handle, desc.iManufacturer, buffer, 256) >= 0);
    printf("Manufacturer: %s\n", buffer);
    assert(libusb_get_string_descriptor_ascii(handle, desc.iProduct, buffer, 256) >= 0);
    printf("Product: %s\n", buffer);
    if (libusb_get_string_descriptor_ascii(handle, desc.iSerialNumber, buffer, 256) >= 0)
        printf("Serial No: %s\n", buffer);
    libusb_exit(context);
}

This utility shows some basic information about a usb device. It takes the device file descriptor as its only command-line argument. Let's compile it:

gcc usbtest.c -lusb-1.0 -o usbtest

Use the -e option of termux-usb to run ./usbtest with the correct file descriptor:

termux-usb -e ./usbtest /dev/bus/usb/001/002