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authorLee Jones <lee.jones@linaro.org>2016-06-08 12:21:25 +0300
committerThierry Reding <thierry.reding@gmail.com>2016-06-10 17:01:40 +0300
commit1a366fe9153f445e950a7a344932b7419aa83094 (patch)
treeb6d66b37c862446d280a03179c178913d9090aad /drivers/pwm/sysfs.c
parent3a3d1a4e32ab47323d7b8c8b7631a8d36a3098b2 (diff)
downloadlinux-1a366fe9153f445e950a7a344932b7419aa83094.tar.xz
pwm: sysfs: Add PWM capture support
Allow a user to read PWM capture results from sysfs. To start a capture and read the result, simply read the file: $ cat $PWMCHIP/capture The output format is "<period> <duty cycle>". Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm/sysfs.c')
-rw-r--r--drivers/pwm/sysfs.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index d98599249a05..c3b1b563480e 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);