diff options
| -rw-r--r-- | drivers/pwm/core.c | 33 | ||||
| -rw-r--r-- | include/linux/pwm.h | 3 |
2 files changed, 29 insertions, 7 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 3f9df3e..b8f6c30 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -269,6 +269,7 @@ 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); } @@ -473,16 +474,22 @@ int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity) if (!pwm->chip->ops->set_polarity) return -ENOSYS; - if (pwm_is_enabled(pwm)) - return -EBUSY; + mutex_lock(&pwm->lock); + + if (pwm_is_enabled(pwm)) { + err = -EBUSY; + goto unlock; + } err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity); if (err) - return err; + goto unlock; pwm->polarity = polarity; - return 0; +unlock: + mutex_unlock(&pwm->lock); + return err; } EXPORT_SYMBOL_GPL(pwm_set_polarity); @@ -494,10 +501,22 @@ 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; + + 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 pwm ? 0 : -EINVAL; + return err; } EXPORT_SYMBOL_GPL(pwm_enable); diff --git a/include/linux/pwm.h b/include/linux/pwm.h index d681f68..cfc3ed4 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -2,6 +2,7 @@ #define __LINUX_PWM_H #include <linux/err.h> +#include <linux/mutex.h> #include <linux/of.h> struct pwm_device; @@ -87,6 +88,7 @@ enum { * @pwm: global index of the PWM device * @chip: PWM chip providing this PWM device * @chip_data: chip-private data associated with the PWM device + * @lock: used to serialize accesses to the PWM device where necessary * @period: period of the PWM signal (in nanoseconds) * @duty_cycle: duty cycle of the PWM signal (in nanoseconds) * @polarity: polarity of the PWM signal @@ -98,6 +100,7 @@ struct pwm_device { unsigned int pwm; struct pwm_chip *chip; void *chip_data; + struct mutex lock; unsigned int period; unsigned int duty_cycle; |