From 4e2f002f7a9b316640eb06ef6df767f017e3e7b1 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Wed, 6 Jun 2012 15:17:02 +0100 Subject: [PATCH] staging: comedi: describe comedi_recognize() Add a comment to comedi_recognize() to describe what it does as it's a bit confusing. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c index 9d2b206251ac..49e53eaa8e41 100644 --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -300,8 +300,32 @@ static int postconfig(struct comedi_device *dev) return 0; } -/* generic recognize function for drivers - * that register their supported board names */ +/* + * Generic recognize function for drivers that register their supported + * board names. + * + * 'driv->board_name' points to a 'const char *' member within the + * zeroth element of an array of some private board information + * structure, say 'struct foo_board' containing a member 'const char + * *board_name' that is initialized to point to a board name string that + * is one of the candidates matched against this function's 'name' + * parameter. + * + * 'driv->offset' is the size of the private board information + * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is + * the length of the array of private board information structures. + * + * If one of the board names in the array of private board information + * structures matches the name supplied to this function, the function + * returns a pointer to the pointer to the board name, otherwise it + * returns NULL. The return value ends up in the 'board_ptr' member of + * a 'struct comedi_device' that the low-level comedi driver's + * 'attach()' hook can convert to a point to a particular element of its + * array of private board information structures by subtracting the + * offset of the member that points to the board name. (No subtraction + * is required if the board name pointer is the first member of the + * private board information structure, which is generally the case.) + */ static void *comedi_recognize(struct comedi_driver *driv, const char *name) { char **name_ptr = (char **)driv->board_name; -- 2.39.5