Commit 838cb6ab authored by Robert P. J. Day's avatar Robert P. J. Day Committed by Jesper Juhl
Browse files

DOC: A couple corrections and clarifications in USB doc. 



A couple of corrections and clarifications in USB
documentation.

Signed-off-by: default avatarRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: default avatarJesper Juhl <jesper.juhl@gmail.com>
parent 37679011

Documentation/DocBook/writing_usb_driver.tmpl

+7 −7
Original line number Original line Diff line number Diff line
@@ -100,8 +100,8 @@ 
      useful documents, at the USB home page (see Resources). An excellent

      useful documents, at the USB home page (see Resources). An excellent

      introduction to the Linux USB subsystem can be found at the USB Working

      introduction to the Linux USB subsystem can be found at the USB Working

      Devices List (see Resources). It explains how the Linux USB subsystem is

      Devices List (see Resources). It explains how the Linux USB subsystem is

      structured and introduces the reader to the concept of USB urbs, which

      structured and introduces the reader to the concept of USB urbs

      are essential to USB drivers.

      (USB Request Blocks), which are essential to USB drivers.

  </para>

  </para>

  <para>

  <para>

      The first thing a Linux USB driver needs to do is register itself with

      The first thing a Linux USB driver needs to do is register itself with
@@ -162,8 +162,8 @@ static int __init usb_skel_init(void) 
module_init(usb_skel_init);

module_init(usb_skel_init);

  </programlisting>

  </programlisting>

  <para>

  <para>

      When the driver is unloaded from the system, it needs to unregister

      When the driver is unloaded from the system, it needs to deregister

      itself with the USB subsystem. This is done with the usb_unregister

      itself with the USB subsystem. This is done with the usb_deregister

      function:

      function:

  </para>

  </para>

  <programlisting>

  <programlisting>
@@ -232,7 +232,7 @@ static int skel_probe(struct usb_interface *interface, 
     were passed to the USB subsystem will be called from a user program trying

     were passed to the USB subsystem will be called from a user program trying

     to talk to the device. The first function called will be open, as the

     to talk to the device. The first function called will be open, as the

     program tries to open the device for I/O. We increment our private usage

     program tries to open the device for I/O. We increment our private usage

     count and save off a pointer to our internal structure in the file

     count and save a pointer to our internal structure in the file

     structure. This is done so that future calls to file operations will

     structure. This is done so that future calls to file operations will

     enable the driver to determine which device the user is addressing.  All

     enable the driver to determine which device the user is addressing.  All

     of this is done with the following code:

     of this is done with the following code:
@@ -252,8 +252,8 @@ file->private_data = dev; 
     send to the device based on the size of the write urb it has created (this

     send to the device based on the size of the write urb it has created (this

     size depends on the size of the bulk out end point that the device has).

     size depends on the size of the bulk out end point that the device has).

     Then it copies the data from user space to kernel space, points the urb to

     Then it copies the data from user space to kernel space, points the urb to

     the data and submits the urb to the USB subsystem.  This can be shown in

     the data and submits the urb to the USB subsystem.  This can be seen in

     he following code:

     the following code:

  </para>

  </para>

  <programlisting>

  <programlisting>

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

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