Supply a PWM Capture call-back Op in order to pass back
information obtained by running analysis on PWM a signal.
This would normally (at least during testing) be called from
the Sysfs routines with a view to printing out PWM Capture
data which has been encoded into a string.
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
---
drivers/pwm/core.c | 27 +++++++++++++++++++++++++++
include/linux/pwm.h | 25 +++++++++++++++++++++++++
2 files changed, 52 insertions(+)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index dba3843..4678de6 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -525,6 +525,33 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
EXPORT_SYMBOL_GPL(pwm_apply_state);
/**
+ * pwm_capture() - capture and report a PWM signal
+ * @pwm: PWM device
+ * @result: struct to fill with capture result
+ * @timeout_ms: time to wait, in milliseconds, before giving up on capture
+ *
+ * Returns: 0 on success or a negative error code on failure.
+ */
+int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
+ unsigned int timeout_ms)
+{
+ int err;
+
+ if (!pwm || !pwm->chip->ops)
+ return -EINVAL;
+
+ if (!pwm->chip->ops->capture)
+ return -ENOSYS;
+
+ mutex_lock(&pwm_lock);
+ err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout_ms);
+ mutex_unlock(&pwm_lock);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(pwm_capture);
+
+/**
* pwm_adjust_config() - adjust the current PWM config to the PWM arguments
* @pwm: PWM device
*
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 17018f3..13cac27 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -5,7 +5,9 @@
#include <linux/mutex.h>
#include <linux/of.h>
+struct pwm_capture;
struct seq_file;
+
struct pwm_chip;
/**
@@ -153,6 +155,7 @@ static inline void pwm_get_args(const struct pwm_device *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
+ * @capture: capture and report PWM signal
* @enable: enable PWM output toggling
* @disable: disable PWM output toggling
* @apply: atomically apply a new PWM config. The state argument
@@ -172,6 +175,8 @@ struct pwm_ops {
int duty_ns, int period_ns);
int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm,
enum pwm_polarity polarity);
+ int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_capture *result, unsigned int timeout_ms);
int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -212,6 +217,16 @@ struct pwm_chip {
bool can_sleep;
};
+/**
+ * struct pwm_capture - PWM capture data
+ * @period: period of the PWM signal (in nanoseconds)
+ * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
+ */
+struct pwm_capture {
+ unsigned long long period;
+ unsigned long long duty_cycle;
+};
+
#if IS_ENABLED(CONFIG_PWM)
/* PWM user APIs */
struct pwm_device *pwm_request(int pwm_id, const char *label);
@@ -322,6 +337,9 @@ static inline void pwm_disable(struct pwm_device *pwm)
/* PWM provider APIs */
+int pwm_capture(struct pwm_device *pwm,
+ struct pwm_capture *result,
+ unsigned int timeout_ms);
int pwm_set_chip_data(struct pwm_device *pwm, void *data);
void *pwm_get_chip_data(struct pwm_device *pwm);
@@ -373,6 +391,13 @@ static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
return -EINVAL;
}
+static inline int pwm_capture(struct pwm_device *pwm,
+ struct pwm_capture *result,
+ unsigned int timeout_ms)
+{
+ return -EINVAL;
+}
+
static inline int pwm_set_polarity(struct pwm_device *pwm,
enum pwm_polarity polarity)
{
--
2.8.3
--
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