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Subject[PATCH 2/2] [2/2] extcon: optimising the check_mutually_exclusive function
Date
From: anish kumar <anish198519851985@gmail.com>

Rather than re-inventing the wheel we can use the hamming function
to calculate the number of bits set to check for violation of
exclusivity.

Signed-off-by: anish kumar <anish198519851985@gmail.com>
---
drivers/extcon/extcon-class.c | 14 +++++---------
1 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/extcon/extcon-class.c b/drivers/extcon/extcon-class.c
index e09a6c3..06df95a 100644
--- a/drivers/extcon/extcon-class.c
+++ b/drivers/extcon/extcon-class.c
@@ -89,17 +89,13 @@ static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state)
return 0;

for (i = 0; edev->mutually_exclusive[i]; i++) {
- int count = 0, j;
+ int weight;
u32 correspondants = new_state & edev->mutually_exclusive[i];
- u32 exp = 1;
-
- for (j = 0; j < 32; j++) {
- if (exp & correspondants)
- count++;
- if (count > 1)
- return i + 1;
- exp <<= 1;
- }
+
+ /* calculate the total number of bits set */
+ weight = hweight32(correspondants);
+ if (weight > 1)
+ return i + 1;
}

return 0;
--
1.7.1


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