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    Subject[PATCH v3 10/20] pwm: sysfs: Add PWM Capture support
    Date
    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>
    ---
    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);
    --
    2.8.3
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