• H Hartley Sweeten's avatar
    staging: comedi: cleanup all the comedi_driver 'detach' functions · 484ecc95
    H Hartley Sweeten authored
    
    
    1. Change the return type from int to void
    
    All the detach functions, except for the comedi usb drivers, simply
    return success (0). Plus, the return code is never checked in the
    comedi core.
    
    The comedi usb drivers do return error codes but the conditions can
    never happen.
    
    The first check is:
    
    	if (!dev)
    		return -EFAULT;
    
    This checks that the passed comedi_device pointer is valid. The detach
    function itself is called using this pointer so it MUST always be valid
    or there is a bug in the core:
    
    	if (dev->driver)
    		dev->driver->detach(dev);
    
    And the second check:
    
    	usb = dev->private;
    	if (!usb)
    		return -EFAULT;
    
    The dev->private pointer is setup in the attach function to point to the
    probed usb device. This value could be NULL if the attach fails. But,
    since the comedi core is going to unload the driver anyway and does not
    check for errors there is no gain by returning one.
    
    After removing these checks from the comedi usb drivers the detach
    functions required a bit of cleanup.
    
    2. Remove all the printk noise in the detach functions
    
    All of the printk output is really just noise. The user did a rmmod to
    unload the driver, we really don't need to tell them about it.
    
    Also, some of the messages are output using:
    
    	dev_dbg(dev->hw_dev, ...
    or
    	dev_info(dev->hw_dev, ...
    
    Unfortunately the hw_dev value is only used by drivers that are doing
    DMA. For most drivers this variable is going to be NULL so the output
    is not going to work as expected.
    
    3. Refactor a couple static 'free_resource' functions into the detach
       functions.
    
    The 'free_resource' function is only being called by the detach and it
    makes more sense to just absorb the code.
    
    4. Remove a couple unnecessary braces for single statements.
    
    5. Remove unnecessary comments.
    
    Most of the comedi drivers appear to be based on the comedi skel driver
    and have the comments from that driver included. These comments make
    sense in the skel driver for reference but they don't need to be in any
    of the actual drivers.
    
    6. Remove all the extra whitespace.
    
    It's not needed to make the functions any more readable.
    
    7. Remove the now unused 'attached_successfully' variable in the
       cb_pcimdda driver.
    
    This variable was only used to conditionally output some driver noise
    during the detach. Since all the printk's have been removed this
    variable is no longer necessary.
    
    Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
    Cc: Ian Abbott <abbotti@mev.co.uk>
    Cc: Mori Hess <fmhess@users.sourceforge.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    484ecc95