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thierryredingthierryreding
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Merge branch 'for-4.8/capture' into for-next
2 parents 489babe + 1a366fe commit bd26861

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‎Documentation/ABI/testing/sysfs-class-pwm

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@@ -77,3 +77,12 @@ Description:
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Enable/disable the PWM signal.
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0 is disabled
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1 is enabled
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What: /sys/class/pwm/pwmchipN/pwmX/capture
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Date: June 2016
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KernelVersion: 4.8
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Contact: Lee Jones <lee.jones@linaro.org>
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Description:
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Capture information about a PWM signal. The output format is a
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pair unsigned integers (period and duty cycle), separated by a
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single space.

‎drivers/pwm/core.c

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Original file line numberDiff line numberDiff line change
@@ -525,6 +525,33 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
525525
}
526526
EXPORT_SYMBOL_GPL(pwm_apply_state);
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528+
/**
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* pwm_capture() - capture and report a PWM signal
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* @pwm: PWM device
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* @result: structure to fill with capture result
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* @timeout: time to wait, in milliseconds, before giving up on capture
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*
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* Returns: 0 on success or a negative error code on failure.
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*/
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int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
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unsigned long timeout)
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{
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int err;
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541+
if (!pwm || !pwm->chip->ops)
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return -EINVAL;
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if (!pwm->chip->ops->capture)
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return -ENOSYS;
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mutex_lock(&pwm_lock);
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err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
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mutex_unlock(&pwm_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(pwm_capture);
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/**
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* pwm_adjust_config() - adjust the current PWM config to the PWM arguments
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* @pwm: PWM device

‎drivers/pwm/sysfs.c

Lines changed: 17 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -208,16 +208,33 @@ static ssize_t polarity_store(struct device *child,
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return ret ? : size;
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}
210210

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static ssize_t capture_show(struct device *child,
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struct device_attribute *attr,
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char *buf)
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{
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struct pwm_device *pwm = child_to_pwm_device(child);
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struct pwm_capture result;
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int ret;
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ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
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if (ret)
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return ret;
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return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
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}
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211226
static DEVICE_ATTR_RW(period);
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static DEVICE_ATTR_RW(duty_cycle);
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static DEVICE_ATTR_RW(enable);
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static DEVICE_ATTR_RW(polarity);
230+
static DEVICE_ATTR_RO(capture);
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static struct attribute *pwm_attrs[] = {
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&dev_attr_period.attr,
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&dev_attr_duty_cycle.attr,
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&dev_attr_enable.attr,
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&dev_attr_polarity.attr,
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&dev_attr_capture.attr,
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NULL
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};
223240
ATTRIBUTE_GROUPS(pwm);

‎include/linux/pwm.h

Lines changed: 24 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,9 @@
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#include <linux/mutex.h>
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#include <linux/of.h>
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8+
struct pwm_capture;
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struct seq_file;
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struct pwm_chip;
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/**
@@ -241,6 +243,7 @@ pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle,
241243
* @free: optional hook for freeing a PWM
242244
* @config: configure duty cycles and period length for this PWM
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* @set_polarity: configure the polarity of this PWM
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* @capture: capture and report PWM signal
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* @enable: enable PWM output toggling
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* @disable: disable PWM output toggling
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* @apply: atomically apply a new PWM config. The state argument
@@ -260,6 +263,8 @@ struct pwm_ops {
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int duty_ns, int period_ns);
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int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm,
262265
enum pwm_polarity polarity);
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int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm,
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struct pwm_capture *result, unsigned long timeout);
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int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
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void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
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int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -300,6 +305,16 @@ struct pwm_chip {
300305
bool can_sleep;
301306
};
302307

308+
/**
309+
* struct pwm_capture - PWM capture data
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* @period: period of the PWM signal (in nanoseconds)
311+
* @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
312+
*/
313+
struct pwm_capture {
314+
unsigned int period;
315+
unsigned int duty_cycle;
316+
};
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303318
#if IS_ENABLED(CONFIG_PWM)
304319
/* PWM user APIs */
305320
struct pwm_device *pwm_request(int pwm_id, const char *label);
@@ -412,6 +427,8 @@ static inline void pwm_disable(struct pwm_device *pwm)
412427
}
413428

414429
/* PWM provider APIs */
430+
int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
431+
unsigned long timeout);
415432
int pwm_set_chip_data(struct pwm_device *pwm, void *data);
416433
void *pwm_get_chip_data(struct pwm_device *pwm);
417434

@@ -463,6 +480,13 @@ static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
463480
return -EINVAL;
464481
}
465482

483+
static inline int pwm_capture(struct pwm_device *pwm,
484+
struct pwm_capture *result,
485+
unsigned long timeout)
486+
{
487+
return -EINVAL;
488+
}
489+
466490
static inline int pwm_set_polarity(struct pwm_device *pwm,
467491
enum pwm_polarity polarity)
468492
{

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