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SubjectRe: [PATCH 2/2] [2/2] extcon: optimising the check_mutually_exclusive function
> 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>

Ah.. we've got such a convinient one. Thanks.

Singed-off-by: MyungJoo Ham <myungjoo.ham@samsung.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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