[PATCH v3 10/20] pwm: sysfs: Add PWM Capture support
From: Lee Jones <hidden>
Date: 2016-06-08 09:27:31
Also in:
linux-arm-kernel, linux-pwm, lkml
Subsystem:
pwm subsystem, the rest · Maintainers:
Uwe Kleine-König, Linus Torvalds
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 <redacted> --- drivers/pwm/sysfs.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index d985992..901e647 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, "%llu %llu\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);
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2.8.3