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| author | anish kumar <anish198519851985@gmail.com> | 2012-08-29 23:05:10 +0400 |
|---|---|---|
| committer | MyungJoo Ham <myungjoo.ham@samsung.com> | 2012-10-22 06:28:10 +0400 |
| commit | 28c0ada62d39eaafef03d88a4e6f4c5bcb6e1b6c (patch) | |
| tree | 6f4f01eab4ad9c1e59265362a3077a50449cba60 /drivers/extcon | |
| parent | 0cf6ad8a18f7f7bdbb81975188d9e0656ef277dd (diff) | |
| download | linux-28c0ada62d39eaafef03d88a4e6f4c5bcb6e1b6c.tar.xz | |
extcon: optimising the check_mutually_exclusive function
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>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Diffstat (limited to 'drivers/extcon')
| -rw-r--r-- | drivers/extcon/extcon-class.c | 16 |
1 files changed, 6 insertions, 10 deletions
diff --git a/drivers/extcon/extcon-class.c b/drivers/extcon/extcon-class.c index 1e1a3f17a782..1ce76a8d777b 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; |