Add periodic polling functionality to SYSFS trigger
Signed-off-by: Vladimir Barinov <vladimir.barinov@xxxxxxxxxxxxxxxxxx>
---
Changes in version 2:
- initially added
Changes in version 3:
- fixed typos in ABI description
.../ABI/testing/sysfs-bus-iio-trigger-sysfs | 11 ++++
drivers/iio/trigger/iio-trig-sysfs.c | 58 ++++++++++++++++++++++
2 files changed, 69 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs b/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs
index 5235e6c..03c18eb 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs
+++ b/Documentation/ABI/testing/sysfs-bus-iio-trigger-sysfs
@@ -9,3 +9,14 @@ Description:
automated testing or in situations, where other trigger methods
are not applicable. For example no RTC or spare GPIOs.
X is the IIO index of the trigger.
+
+What: /sys/bus/iio/devices/triggerX/trigger_poll
+KernelVersion: 4.2.0
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ This file is provided by the iio-trig-sysfs stand-alone trigger
+ driver. Writing this file with positive value (in milliseconds)
+ will start periodic event triggering of the driver, associated
+ with this trigger. Writing this file with 0 will stop periodic
+ triggering.
+ X is the IIO index of the trigger.
diff --git a/drivers/iio/trigger/iio-trig-sysfs.c b/drivers/iio/trigger/iio-trig-sysfs.c
index 3dfab2b..ea79311 100644
--- a/drivers/iio/trigger/iio-trig-sysfs.c
+++ b/drivers/iio/trigger/iio-trig-sysfs.c
@@ -18,6 +18,8 @@
struct iio_sysfs_trig {
struct iio_trigger *trig;
struct irq_work work;
+ struct delayed_work poll_work;
+ unsigned int poll_interval; /* msec */
int id;
struct list_head l;
};
@@ -110,10 +112,63 @@ static ssize_t iio_sysfs_trigger_poll(struct device *dev,
return count;
}
+static void iio_sysfs_trigger_queue_poll_work(struct iio_sysfs_trig *trig)
+{
+ unsigned long delay;
+
+ delay = msecs_to_jiffies(trig->poll_interval);
+ if (delay >= HZ)
+ delay = round_jiffies_relative(delay);
+
+ queue_delayed_work(system_freezable_wq, &trig->poll_work, delay);
+}
+
+static void iio_sysfs_trigger_poll_work(struct work_struct *work)
+{
+ struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig,
+ poll_work.work);
+
+ irq_work_queue(&trig->work);
+ iio_sysfs_trigger_queue_poll_work(trig);
+}
+
+static ssize_t iio_sysfs_trigger_get_poll(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_trigger *trig = to_iio_trigger(dev);
+ struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig);
+
+ return sprintf(buf, "%d\n", sysfs_trig->poll_interval);
+}
+
+static ssize_t iio_sysfs_trigger_set_poll(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct iio_trigger *trig = to_iio_trigger(dev);
+ struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig);
+ unsigned int interval;
+ int err;
+
+ err = kstrtouint(buf, 0, &interval);
+ if (err)
+ return err;
+
+ sysfs_trig->poll_interval = interval;
+
+ cancel_delayed_work_sync(&sysfs_trig->poll_work);
+ if (sysfs_trig->poll_interval > 0)
+ iio_sysfs_trigger_queue_poll_work(sysfs_trig);
+
+ return count;
+}
+
static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
+static DEVICE_ATTR(trigger_poll, S_IRUGO | S_IWUSR, iio_sysfs_trigger_get_poll,
+ iio_sysfs_trigger_set_poll);
static struct attribute *iio_sysfs_trigger_attrs[] = {
&dev_attr_trigger_now.attr,
+ &dev_attr_trigger_poll.attr,
NULL,
};
@@ -164,6 +219,7 @@ static int iio_sysfs_trigger_probe(int id)
iio_trigger_set_drvdata(t->trig, t);
init_irq_work(&t->work, iio_sysfs_trigger_work);
+ INIT_DELAYED_WORK(&t->poll_work, iio_sysfs_trigger_poll_work);
ret = iio_trigger_register(t->trig);
if (ret)
@@ -198,6 +254,8 @@ static int iio_sysfs_trigger_remove(int id)
return -EINVAL;
}
+ cancel_delayed_work_sync(&t->poll_work);
+
iio_trigger_unregister(t->trig);
iio_trigger_free(t->trig);
--
1.9.1
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