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authorH Hartley Sweeten <hartleys@visionengravers.com>2013-06-11 10:38:59 -0700
committerThierry Reding <thierry.reding@gmail.com>2013-06-21 11:32:51 +0200
commit76abbdde2d95a3807d0dc6bf9f84d03d0dbd4f3d (patch)
tree63a5476d6fbf80ec90b813461ec7ec67ff462684 /drivers/pwm/core.c
parent3dd0a909479c1d372341d749b4ff94cd638b57da (diff)
downloadlinux-76abbdde2d95a3807d0dc6bf9f84d03d0dbd4f3d.tar.bz2
pwm: Add sysfs interface
Add a simple sysfs interface to the generic PWM framework. /sys/class/pwm/ `-- pwmchipN/ for each PWM chip |-- export (w/o) ask the kernel to export a PWM channel |-- npwm (r/o) number of PWM channels in this PWM chip |-- pwmX/ for each exported PWM channel | |-- duty_cycle (r/w) duty cycle (in nanoseconds) | |-- enable (r/w) enable/disable PWM | |-- period (r/w) period (in nanoseconds) | `-- polarity (r/w) polarity of PWM (normal/inversed) `-- unexport (w/o) return a PWM channel to the kernel Based on work by Lars Poeschel. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Lars Poeschel <poeschel@lemonage.de> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm/core.c')
-rw-r--r--drivers/pwm/core.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 0cf0f65eb037..dfbfbc521768 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -274,6 +274,8 @@ int pwmchip_add(struct pwm_chip *chip)
if (IS_ENABLED(CONFIG_OF))
of_pwmchip_add(chip);
+ pwmchip_sysfs_export(chip);
+
out:
mutex_unlock(&pwm_lock);
return ret;
@@ -310,6 +312,8 @@ int pwmchip_remove(struct pwm_chip *chip)
free_pwms(chip);
+ pwmchip_sysfs_unexport(chip);
+
out:
mutex_unlock(&pwm_lock);
return ret;
@@ -402,10 +406,19 @@ EXPORT_SYMBOL_GPL(pwm_free);
*/
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
+ int err;
+
if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
return -EINVAL;
- return pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
+ err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
+ if (err)
+ return err;
+
+ pwm->duty_cycle = duty_ns;
+ pwm->period = period_ns;
+
+ return 0;
}
EXPORT_SYMBOL_GPL(pwm_config);
@@ -418,6 +431,8 @@ EXPORT_SYMBOL_GPL(pwm_config);
*/
int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
{
+ int err;
+
if (!pwm || !pwm->chip->ops)
return -EINVAL;
@@ -427,7 +442,13 @@ int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
if (test_bit(PWMF_ENABLED, &pwm->flags))
return -EBUSY;
- return pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
+ err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
+ if (err)
+ return err;
+
+ pwm->polarity = polarity;
+
+ return 0;
}
EXPORT_SYMBOL_GPL(pwm_set_polarity);