[RESEND 01/11] pwm: Add PWM Capture support

Lee Jones
2016-03-02T16:10:08Z

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@linaro.org>
---
drivers/pwm/core.c | 26 ++++++++++++++++++++++++++
include/linux/pwm.h | 13 +++++++++++++
2 files changed, 39 insertions(+)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index d24ca5f..8f4a8a9 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -494,6 +494,32 @@ unlock:
EXPORT_SYMBOL_GPL(pwm_set_polarity);

/**
+ * pwm_capture() - capture and report a PWM signal
+ * @pwm: PWM device
+ * @channel: PWM capture channel to use
+ * @buf: buffer to place output message into
+ *
+ * Returns: 0 on success or a negative error code on failure.
+ */
+int pwm_capture(struct pwm_device *pwm, int channel, char *buf)
+{
+ 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, channel, buf);
+ mutex_unlock(&pwm->lock);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(pwm_capture);
+
+/**
* pwm_enable() - start a PWM output toggling
* @pwm: PWM device
*
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index cfc3ed4..7bcff6b 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -33,6 +33,11 @@ int pwm_enable(struct pwm_device *pwm);
* pwm_disable - stop a PWM output toggling
*/
void pwm_disable(struct pwm_device *pwm);
+
+/*
+ * pwm_capture - capture and report a PWM signal
+ */
+int pwm_capture(struct pwm_device *pwm, int channel, char *buf);
#else
static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
{
@@ -56,6 +61,11 @@ static inline int pwm_enable(struct pwm_device *pwm)
static inline void pwm_disable(struct pwm_device *pwm)
{
}
+
+static inline int pwm_capture(struct pwm_device *pwm, int channel, char *buf)
+{
+ return -EINVAL;
+}
#endif

struct pwm_chip;
@@ -150,6 +160,7 @@ static inline enum pwm_polarity pwm_get_polarity(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
* @dbg_show: optional routine to show contents in debugfs
@@ -162,6 +173,8 @@ 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,
+ int channel, char *buf);
int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
#ifdef CONFIG_DEBUG_FS
--
1.9.1