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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 /include/linux/pwm.h
parent3dd0a909479c1d372341d749b4ff94cd638b57da (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. 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 'include/linux/pwm.h')
-rw-r--r--include/linux/pwm.h29
1 files changed, 28 insertions, 1 deletions
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index a4df2042b79..f0feafd184a 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -76,6 +76,7 @@ enum pwm_polarity {
enum {
PWMF_REQUESTED = 1 << 0,
PWMF_ENABLED = 1 << 1,
+ PWMF_EXPORTED = 1 << 2,
};
struct pwm_device {
@@ -86,7 +87,9 @@ struct pwm_device {
struct pwm_chip *chip;
void *chip_data;
- unsigned int period; /* in nanoseconds */
+ unsigned int period; /* in nanoseconds */
+ unsigned int duty_cycle; /* in nanoseconds */
+ enum pwm_polarity polarity;
};
static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
@@ -100,6 +103,17 @@ static inline unsigned int pwm_get_period(struct pwm_device *pwm)
return pwm ? pwm->period : 0;
}
+static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
+{
+ if (pwm)
+ pwm->duty_cycle = duty;
+}
+
+static inline unsigned int pwm_get_duty_cycle(struct pwm_device *pwm)
+{
+ return pwm ? pwm->duty_cycle : 0;
+}
+
/*
* pwm_set_polarity - configure the polarity of a PWM signal
*/
@@ -278,4 +292,17 @@ static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
}
#endif
+#ifdef CONFIG_PWM_SYSFS
+void pwmchip_sysfs_export(struct pwm_chip *chip);
+void pwmchip_sysfs_unexport(struct pwm_chip *chip);
+#else
+static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
+{
+}
+
+static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
+{
+}
+#endif /* CONFIG_PWM_SYSFS */
+
#endif /* __LINUX_PWM_H */