Commit e51b156b authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Thierry Reding
Browse files

pwm: Document variables protected by pwm_lock 



To simplify validation of the used locking, document for the global pwm
mutex what it actually protects against concurrent access. Also note for
two functions modifying these that pwm_lock is held by the caller.

Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221117211143.3817381-2-u.kleine-koenig@pengutronix.de


Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent aa3c668f

drivers/pwm/core.c

+5 −0
Original line number Diff line number Diff line
@@ -27,7 +27,10 @@ 


static DEFINE_MUTEX(pwm_lookup_lock);

static LIST_HEAD(pwm_lookup_list);



/* protects access to pwm_chips, allocated_pwms, and pwm_tree */

static DEFINE_MUTEX(pwm_lock);



static LIST_HEAD(pwm_chips);

static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);

static RADIX_TREE(pwm_tree, GFP_KERNEL);
@@ -37,6 +40,7 @@ static struct pwm_device *pwm_to_device(unsigned int pwm) 
	return radix_tree_lookup(&pwm_tree, pwm);

}



/* Called with pwm_lock held */

static int alloc_pwms(unsigned int count)

{

	unsigned int start;
@@ -50,6 +54,7 @@ static int alloc_pwms(unsigned int count) 
	return start;

}



/* Called with pwm_lock held */

static void free_pwms(struct pwm_chip *chip)

{

	unsigned int i;