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 <[email protected]> Reviewed-by: Dmitry Torokhov <[email protected]> Signed-off-by: Jonathan Richardson <[email protected]> --- 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); diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 9daf0ef..50f28e6 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -3,6 +3,7 @@ #include <linux/err.h> #include <linux/of.h> +#include <linux/mutex.h> struct pwm_device; struct seq_file; @@ -86,6 +87,7 @@ struct pwm_device { unsigned int pwm; struct pwm_chip *chip; void *chip_data; + struct mutex lock; unsigned int period; /* in nanoseconds */ unsigned int duty_cycle; /* in nanoseconds */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
