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Commit 3e0f9b2c authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
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staging: comedi: comedidev.h: Document usage of 'detach' handler 



Document when the "detach" handler function pointed to by the `detach`
member of a `struct comedi_driver` is called by the comedi core, and how
the "attach" and "auto_attach" handlers can defer clean-up to it when
they return an error to the comedi core.  This is already mentioned as
part of the documentation for `comedi_auto_config()`, but is useful to
document it for `struct comedi_driver` as well, since
`comedi_auto_config()` is not usually called directly by low-level
comedi drivers, and it is not called at all for "legacy" comedi devices
that are configured manually.

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3c87f653

drivers/staging/comedi/comedidev.h

+12 −0
Original line number Diff line number Diff line
@@ -426,6 +426,18 @@ enum comedi_cb { 
 * handler will be called with the COMEDI device structure's board_ptr member

 * pointing to the matched pointer to a board name within the driver's private

 * array of static, read-only board type information.

 *

 * The @detach handler has two roles.  If a COMEDI device was successfully

 * configured by the @attach or @auto_attach handler, it is called when the

 * device is being deconfigured (by the %COMEDI_DEVCONFIG ioctl, or due to

 * unloading of the driver, or due to device removal).  It is also called when

 * the @attach or @auto_attach handler returns an error.  Therefore, the

 * @attach or @auto_attach handlers can defer clean-up on error until the

 * @detach handler is called.  If the @attach or @auto_attach handlers free

 * any resources themselves, they must prevent the @detach handler from

 * freeing the same resources.  The @detach handler must not assume that all

 * resources requested by the @attach or @auto_attach handler were

 * successfully allocated.

 */

struct comedi_driver {

	/* private: */