TWxSoftware/twx-linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

pwm: Document variables protected by pwm_lock

Browse Source 
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: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221117211143.3817381-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Uwe Kleine-König 2022-12-02 19:35:09 +01:00 committed by Thierry Reding
parent aa3c668f2f
commit e51b156b18
1 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/pwm/core.c
View File

@ -27,7 +27,10 @@
static DEFINE_MUTEX(pwm_lookup_lock); static DEFINE_MUTEX(pwm_lookup_lock);
static LIST_HEAD(pwm_lookup_list); static LIST_HEAD(pwm_lookup_list);
/* protects access to pwm_chips, allocated_pwms, and pwm_tree */
static DEFINE_MUTEX(pwm_lock); static DEFINE_MUTEX(pwm_lock);
static LIST_HEAD(pwm_chips); static LIST_HEAD(pwm_chips);
static DECLARE_BITMAP(allocated_pwms, MAX_PWMS); static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
static RADIX_TREE(pwm_tree, GFP_KERNEL); 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); return radix_tree_lookup(&pwm_tree, pwm);
} }
/* Called with pwm_lock held */
static int alloc_pwms(unsigned int count) static int alloc_pwms(unsigned int count)
{ {
unsigned int start; unsigned int start;
@ -50,6 +54,7 @@ static int alloc_pwms(unsigned int count)
return start; return start;
} }
/* Called with pwm_lock held */
static void free_pwms(struct pwm_chip *chip) static void free_pwms(struct pwm_chip *chip)
{ {
unsigned int i; unsigned int i;