diff options
| -rw-r--r-- | drivers/pwm/core.c | 22 | ||||
| -rw-r--r-- | include/linux/pwm.h | 23 |
2 files changed, 45 insertions, 0 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index c6e05078d3ad..85592e97ef2d 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -379,6 +379,28 @@ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) EXPORT_SYMBOL_GPL(pwm_config); /** + * pwm_set_polarity() - configure the polarity of a PWM signal + * @pwm: PWM device + * @polarity: new polarity of the PWM signal + * + * Note that the polarity cannot be configured while the PWM device is enabled + */ +int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity) +{ + if (!pwm || !pwm->chip->ops) + return -EINVAL; + + if (!pwm->chip->ops->set_polarity) + return -ENOSYS; + + if (test_bit(PWMF_ENABLED, &pwm->flags)) + return -EBUSY; + + return pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity); +} +EXPORT_SYMBOL_GPL(pwm_set_polarity); + +/** * pwm_enable() - start a PWM output toggling * @pwm: PWM device */ diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 21d076c5089e..354764cf5f7a 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -34,6 +34,20 @@ void pwm_disable(struct pwm_device *pwm); #ifdef CONFIG_PWM struct pwm_chip; +/** + * enum pwm_polarity - polarity of a PWM signal + * @PWM_POLARITY_NORMAL: a high signal for the duration of the duty- + * cycle, followed by a low signal for the remainder of the pulse + * period + * @PWM_POLARITY_INVERSED: a low signal for the duration of the duty- + * cycle, followed by a high signal for the remainder of the pulse + * period + */ +enum pwm_polarity { + PWM_POLARITY_NORMAL, + PWM_POLARITY_INVERSED, +}; + enum { PWMF_REQUESTED = 1 << 0, PWMF_ENABLED = 1 << 1, @@ -61,11 +75,17 @@ static inline unsigned int pwm_get_period(struct pwm_device *pwm) return pwm ? pwm->period : 0; } +/* + * pwm_set_polarity - configure the polarity of a PWM signal + */ +int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity); + /** * struct pwm_ops - PWM controller operations * @request: optional hook for requesting a PWM * @free: optional hook for freeing a PWM * @config: configure duty cycles and period length for this PWM + * @set_polarity: configure the polarity of this PWM * @enable: enable PWM output toggling * @disable: disable PWM output toggling * @dbg_show: optional routine to show contents in debugfs @@ -79,6 +99,9 @@ struct pwm_ops { int (*config)(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns); + int (*set_polarity)(struct pwm_chip *chip, + struct pwm_device *pwm, + enum pwm_polarity polarity); int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm); void (*disable)(struct pwm_chip *chip, |