On 15-06-15 02:21 PM, 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 | 19 ++++++++++++++++---
> include/linux/pwm.h | 2 ++
> 2 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> index 76b0386..c255267 100644
> --- a/drivers/pwm/core.c
> +++ b/drivers/pwm/core.c
> @@ -263,6 +263,7 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
> pwm->pwm = chip->base + i;
> pwm->hwpwm = i;
> pwm->polarity = polarity;
> + mutex_init(&pwm->lock);
>
> radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
> }
> @@ -474,10 +475,22 @@ 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 = 0;
>
> - return pwm ? 0 : -EINVAL;
> + if (!pwm)
> + return -EINVAL;
> +
> + mutex_lock(&pwm->lock);
> +
> + 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);
> + }
> +
> + mutex_unlock(&pwm->lock);
> +
> + return err;
> }
> EXPORT_SYMBOL_GPL(pwm_enable);
I meant to add the mutex check in disable also, but what about when
PWMF_ENABLED is checked in pwm_set_polarity() and pwm_dbg_show()?
Thanks.
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