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-rw-r--r--Documentation/ABI/testing/sysfs-class-pwm9
-rw-r--r--drivers/pwm/core.c27
-rw-r--r--drivers/pwm/sysfs.c17
-rw-r--r--include/linux/pwm.h24
4 files changed, 77 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-pwm b/Documentation/ABI/testing/sysfs-class-pwm
index c479d77b67c5..c20e61354561 100644
--- a/Documentation/ABI/testing/sysfs-class-pwm
+++ b/Documentation/ABI/testing/sysfs-class-pwm
@@ -77,3 +77,12 @@ Description:
Enable/disable the PWM signal.
0 is disabled
1 is enabled
+
+What: /sys/class/pwm/pwmchipN/pwmX/capture
+Date: June 2016
+KernelVersion: 4.8
+Contact: Lee Jones <lee.jones@linaro.org>
+Description:
+ Capture information about a PWM signal. The output format is a
+ pair unsigned integers (period and duty cycle), separated by a
+ single space.
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index ed337a8c34ab..0dbd29e287db 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -526,6 +526,33 @@ 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: structure to fill with capture result
+ * @timeout: 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 long timeout)
+{
+ 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);
+ 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/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 01695d48dd54..18ed725594c3 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -208,16 +208,33 @@ static ssize_t polarity_store(struct device *child,
return ret ? : size;
}
+static ssize_t capture_show(struct device *child,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pwm_device *pwm = child_to_pwm_device(child);
+ struct pwm_capture result;
+ int ret;
+
+ ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
+}
+
static DEVICE_ATTR_RW(period);
static DEVICE_ATTR_RW(duty_cycle);
static DEVICE_ATTR_RW(enable);
static DEVICE_ATTR_RW(polarity);
+static DEVICE_ATTR_RO(capture);
static struct attribute *pwm_attrs[] = {
&dev_attr_period.attr,
&dev_attr_duty_cycle.attr,
&dev_attr_enable.attr,
&dev_attr_polarity.attr,
+ &dev_attr_capture.attr,
NULL
};
ATTRIBUTE_GROUPS(pwm);
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 47e66bfb8cb4..f1bbae014889 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;
/**
@@ -241,6 +243,7 @@ pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle,
* @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
@@ -260,6 +263,8 @@ 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 long timeout);
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,
@@ -300,6 +305,16 @@ 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 int period;
+ unsigned int duty_cycle;
+};
+
#if IS_ENABLED(CONFIG_PWM)
/* PWM user APIs */
struct pwm_device *pwm_request(int pwm_id, const char *label);
@@ -412,6 +427,8 @@ static inline void pwm_disable(struct pwm_device *pwm)
}
/* PWM provider APIs */
+int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
+ unsigned long timeout);
int pwm_set_chip_data(struct pwm_device *pwm, void *data);
void *pwm_get_chip_data(struct pwm_device *pwm);
@@ -463,6 +480,13 @@ 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 long timeout)
+{
+ return -EINVAL;
+}
+
static inline int pwm_set_polarity(struct pwm_device *pwm,
enum pwm_polarity polarity)
{