diff options
| author | H Hartley Sweeten <hartleys@visionengravers.com> | 2013-06-11 10:38:59 -0700 |
|---|---|---|
| committer | Winnie Hsu <whsu@nvidia.com> | 2014-09-03 18:03:14 -0700 |
| commit | 8e837f9cce974ed641a43535f1185371d68a592c (patch) | |
| tree | 34972965ad2b284eea568fbc58e2a14380a26d86 /drivers/pwm/core.c | |
| parent | ac954dd4168e97d41d68d79d530144333a8ef132 (diff) | |
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.
Bug 200028381
Change-Id: I0c9c6ad2ca7173e6fc3fbe1d3cd3963cde00539a
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>
Signed-off-by: Bibek Basu <bbasu@nvidia.com>
(cherry picked from commit 76abbdde2d95a3807d0dc6bf9f84d03d0dbd4f3d)
Reviewed-on: http://git-master/r/455068
(cherry picked from commit b1824bc0325f84ea04dab7d6d4f7c887c80b1982)
Reviewed-on: http://git-master/r/488690
GVS: Gerrit_Virtual_Submit
Reviewed-by: Winnie Hsu <whsu@nvidia.com>
Tested-by: Winnie Hsu <whsu@nvidia.com>
Diffstat (limited to 'drivers/pwm/core.c')
| -rw-r--r-- | drivers/pwm/core.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 32221cb0cbe7..9e9f5b8c57f3 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); |