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authorJonathan Richardson <jonathar@broadcom.com>2015-10-16 17:40:58 -0700
committerThierry Reding <thierry.reding@gmail.com>2015-11-10 13:06:16 +0100
commitd1cd21427747f15920cd726f5f67a07880e7dee4 (patch)
tree429e8844a75def440f47479f751e60f9ff685f0c /drivers/pwm
parentf080be27d7d9333e4815655a2cedab91c3aa7acc (diff)
pwm: Set enable state properly on failed call to enable
The pwm_enable() function didn't clear the enabled bit if a call to the driver's ->enable() callback 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 <jonathar@broadcom.com> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Jonathan Richardson <jonathar@broadcom.com> [thierry.reding@gmail.com: add missing kerneldoc for the lock] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/core.c33
1 files changed, 26 insertions, 7 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 3f9df3ea3350..b8f6c309c160 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);