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Message-Id: <1461320295-20414-2-git-send-email-lee.jones@linaro.org>
Date: Fri, 22 Apr 2016 11:18:05 +0100
From: Lee Jones <lee.jones@...aro.org>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: kernel@...inux.com, maxime.coquelin@...com,
linux-pwm@...r.kernel.org, thierry.reding@...il.com,
ajitpal.singh@...com, Lee Jones <lee.jones@...aro.org>
Subject: [[PATCH v2] 01/11] pwm: Add PWM Capture support
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@...aro.org>
---
drivers/pwm/core.c | 27 +++++++++++++++++++++++++++
include/linux/pwm.h | 28 ++++++++++++++++++++++++++++
2 files changed, 55 insertions(+)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 7831bc6..160784d 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -494,6 +494,33 @@ unlock:
EXPORT_SYMBOL_GPL(pwm_set_polarity);
/**
+ * 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_enable() - start a PWM output toggling
* @pwm: PWM device
*
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index cfc3ed4..49f9648 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -6,6 +6,7 @@
#include <linux/of.h>
struct pwm_device;
+struct pwm_capture;
struct seq_file;
#if IS_ENABLED(CONFIG_PWM)
@@ -33,6 +34,13 @@ 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,
+ struct pwm_capture *result,
+ unsigned int timeout_ms);
#else
static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
{
@@ -56,6 +64,13 @@ 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,
+ struct pwm_capture *result,
+ unsigned int timeout_ms)
+{
+ return -EINVAL;
+}
#endif
struct pwm_chip;
@@ -107,6 +122,16 @@ struct pwm_device {
enum pwm_polarity polarity;
};
+/**
+ * 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;
+};
+
static inline bool pwm_is_enabled(const struct pwm_device *pwm)
{
return test_bit(PWMF_ENABLED, &pwm->flags);
@@ -150,6 +175,7 @@ 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 +188,8 @@ 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);
#ifdef CONFIG_DEBUG_FS
--
2.8.0
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