diff options
| author | Lars-Peter Clausen <lars@metafoo.de> | 2012-09-06 10:05:00 +0100 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2012-09-06 22:00:28 +0100 |
| commit | f38bc926d022ebd67baad6ac7fc22c95fbc6238c (patch) | |
| tree | 807902c14117a60e161adec48ee00dd8c0e74cb6 | |
| parent | ed5514c925a0e1266e70630092a77bd0c89aee1f (diff) | |
staging:iio:sysfs-trigger: Use irq_work to properly active trigger
Since iio_trigger_poll() calls generic_handle_irq() it need to be called from
hardirq context. The sysfs trigger is kicked from userspace, so it is obviously
not possible to fulfill this requirement by calling iio_trigger_poll directly.
As a workaround commit 1f785681 ("staging:iio:trigger sysfs userspace trigger
rework.") added iio_trigger_poll_chained() which uses handle_nested_irq instead
of generic_handle_irq. This in itself is a hack and only works by chance.
handle_nested_irq is intended to be called from the threaded interrupt handler
of the parent IRQ. Using handle_nested_irq is also problematic since it will
only call the threaded handler of the IRQ. But quite a few IIO drivers rely on
their hardirq handler being called or undefined behaviour will occur.
This patch uses the irq_work framework to schedule the call to
iio_trigger_poll() from hardirq context, which fixes the issues described above.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
| -rw-r--r-- | drivers/staging/iio/trigger/Kconfig | 2 | ||||
| -rw-r--r-- | drivers/staging/iio/trigger/iio-trig-sysfs.c | 17 |
2 files changed, 18 insertions, 1 deletions
diff --git a/drivers/staging/iio/trigger/Kconfig b/drivers/staging/iio/trigger/Kconfig index b8abf5473ddc..7d3207559265 100644 --- a/drivers/staging/iio/trigger/Kconfig +++ b/drivers/staging/iio/trigger/Kconfig @@ -21,6 +21,8 @@ config IIO_GPIO_TRIGGER config IIO_SYSFS_TRIGGER tristate "SYSFS trigger" depends on SYSFS + depends on HAVE_IRQ_WORK + select IRQ_WORK help Provides support for using SYSFS entry as IIO triggers. If unsure, say N (but it's safe to say "Y"). diff --git a/drivers/staging/iio/trigger/iio-trig-sysfs.c b/drivers/staging/iio/trigger/iio-trig-sysfs.c index fee474648108..3bac97224bf4 100644 --- a/drivers/staging/iio/trigger/iio-trig-sysfs.c +++ b/drivers/staging/iio/trigger/iio-trig-sysfs.c @@ -10,12 +10,14 @@ #include <linux/platform_device.h> #include <linux/slab.h> #include <linux/list.h> +#include <linux/irq_work.h> #include <linux/iio/iio.h> #include <linux/iio/trigger.h> struct iio_sysfs_trig { struct iio_trigger *trig; + struct irq_work work; int id; struct list_head l; }; @@ -89,11 +91,21 @@ static struct device iio_sysfs_trig_dev = { .release = &iio_trigger_sysfs_release, }; +static void iio_sysfs_trigger_work(struct irq_work *work) +{ + struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig, + work); + + iio_trigger_poll(trig->trig, 0); +} + static ssize_t iio_sysfs_trigger_poll(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct iio_trigger *trig = to_iio_trigger(dev); - iio_trigger_poll_chained(trig, 0); + struct iio_sysfs_trig *sysfs_trig = trig->private_data; + + irq_work_queue(&sysfs_trig->work); return count; } @@ -148,6 +160,9 @@ static int iio_sysfs_trigger_probe(int id) t->trig->dev.groups = iio_sysfs_trigger_attr_groups; t->trig->ops = &iio_sysfs_trigger_ops; t->trig->dev.parent = &iio_sysfs_trig_dev; + t->trig->private_data = t; + + init_irq_work(&t->work, iio_sysfs_trigger_work); ret = iio_trigger_register(t->trig); if (ret) |