Commit 6352f24b authored by Philipp Hortmann's avatar Philipp Hortmann Committed by Greg Kroah-Hartman
Browse files

Docs: usb: update writesize, copy_from_user, usb_fill_bulk_urb, usb_submit_urb 



update code examples writesize, copy_from_user, usb_fill_bulk_urb,
usb_submit_urb in skel_write() according to usb-skeleton.c

Signed-off-by: default avatarPhilipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/0c581a83dfc1a8c37e97dfa7279d333f367a9787.1635591623.git.philipp.g.hortmann@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 925ed163

Documentation/driver-api/usb/writing_usb_driver.rst

+13 −11
Original line number Diff line number Diff line
@@ -188,24 +188,26 @@ space, points the urb to the data and submits the urb to the USB 
subsystem. This can be seen in the following code::



    /* we can only write as much as 1 urb will hold */

    bytes_written = (count > skel->bulk_out_size) ? skel->bulk_out_size : count;

    size_t writesize = min_t(size_t, count, MAX_TRANSFER);



    /* copy the data from user space into our urb */

    copy_from_user(skel->write_urb->transfer_buffer, buffer, bytes_written);

    copy_from_user(buf, user_buffer, writesize);



    /* set up our urb */

    usb_fill_bulk_urb(skel->write_urb,

		      skel->dev,

		      usb_sndbulkpipe(skel->dev, skel->bulk_out_endpointAddr),

		      skel->write_urb->transfer_buffer,

		      bytes_written,

    usb_fill_bulk_urb(urb,

		      dev->udev,

		      usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),

		      buf,

		      writesize,

		      skel_write_bulk_callback,

		      skel);

		      dev);



    /* send the data out the bulk port */

    result = usb_submit_urb(skel->write_urb);

    if (result) {

	    err("Failed submitting write urb, error %d", result);

    retval = usb_submit_urb(urb, GFP_KERNEL);

    if (retval) {

	    dev_err(&dev->interface->dev,

                "%s - failed submitting write urb, error %d\n",

                __func__, retval);

    }