On Tue, May 26, 2015 at 01:08:20PM -0700, Jonathan Richardson wrote:
> The pwm_enable function didn't clear the enabled bit if a call to a
> clients enable function returned an error. The result was that the state
> of the pwm core was wrong. Clearing the bit when enable returns an error
> ensures the state is properly set.
>
> Tested-by: Jonathan Richardson <jonat...@broadcom.com>
> Reviewed-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
> Signed-off-by: Jonathan Richardson <jonat...@broadcom.com>
> ---
> drivers/pwm/core.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> index 224645f..18f5ac4 100644
> --- a/drivers/pwm/core.c
> +++ b/drivers/pwm/core.c
> @@ -477,10 +477,20 @@ EXPORT_SYMBOL_GPL(pwm_set_polarity);
> */
> int pwm_enable(struct pwm_device *pwm)
> {
> - if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
> - return pwm->chip->ops->enable(pwm->chip, pwm);
> + int err;
> +
> + if (!pwm)
> + return -EINVAL;
> +
> + if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
> + err = pwm->chip->ops->enable(pwm->chip, pwm);
> + if (err) {
> + clear_bit(PWMF_ENABLED, &pwm->flags);
> + return err;
> + }
> + }I think with this new pattern we're now actually going to need a lock to make sure pwm->flags doesn't change between the test_and_set_bit() and clear_bit() calls. Thierry
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