[RESEND 02/11] pwm: sysfs: Add PWM Capture support

Lee Jones
2016-03-02T15:45:00Z

Allow a user to read PWM Capture results from /sysfs. First,
the user must tell PWM Capture which channel they wish to
read from:

$ echo 2 > $PWMCHIP/capture

To start a capture and read the result, simply read the file:

$ cat $PWMCHIP/capture

The output format is left to the device.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/pwm/sysfs.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 9c90886..3572ef4 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -23,6 +23,8 @@
#include <linux/kdev_t.h>
#include <linux/pwm.h>

+static int capture_channel;
+
struct pwm_export {
struct device child;
struct pwm_device *pwm;
@@ -167,16 +169,42 @@ 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);
+
+ return pwm_capture(pwm, capture_channel, buf);
+}
+
+static ssize_t capture_store(struct device *child,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ int val, ret;
+
+ ret = kstrtoint(buf, 0, &val);
+ if (ret)
+ return ret;
+
+ capture_channel = val;
+
+ return size;
+}
+
static DEVICE_ATTR_RW(period);
static DEVICE_ATTR_RW(duty_cycle);
static DEVICE_ATTR_RW(enable);
static DEVICE_ATTR_RW(polarity);
+static DEVICE_ATTR_RW(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);
--
1.9.1