From bc2b7dab629a51e8beb5fda4222c62a23b729f26 Mon Sep 17 00:00:00 2001 From: Gregor Boirie Date: Wed, 9 Mar 2016 19:05:49 +0100 Subject: iio:core: timestamping clock selection support Adds a new per-device sysfs attribute "current_timestamp_clock" to allow userspace to select a particular POSIX clock for buffered samples and events timestamping. Following clocks, as listed in clock_gettime(2), are supported: CLOCK_REALTIME, CLOCK_MONOTONIC, CLOCK_MONOTONIC_RAW, CLOCK_REALTIME_COARSE, CLOCK_MONOTONIC_COARSE, CLOCK_BOOTTIME and CLOCK_TAI. Signed-off-by: Gregor Boirie Acked-by: Sanchayan Maity Signed-off-by: Jonathan Cameron --- drivers/iio/industrialio-event.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'drivers/iio/industrialio-event.c') diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c index cae332b1d7ea..0ebfc923a997 100644 --- a/drivers/iio/industrialio-event.c +++ b/drivers/iio/industrialio-event.c @@ -44,6 +44,11 @@ struct iio_event_interface { struct mutex read_lock; }; +bool iio_event_enabled(const struct iio_event_interface *ev_int) +{ + return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags); +} + /** * iio_push_event() - try to add event to the list for userspace reading * @indio_dev: IIO device structure @@ -60,7 +65,7 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp) int copied; /* Does anyone care? */ - if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { + if (iio_event_enabled(ev_int)) { ev.id = ev_code; ev.timestamp = timestamp; @@ -180,8 +185,14 @@ int iio_event_getfd(struct iio_dev *indio_dev) if (ev_int == NULL) return -ENODEV; - if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) - return -EBUSY; + fd = mutex_lock_interruptible(&indio_dev->mlock); + if (fd) + return fd; + + if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { + fd = -EBUSY; + goto unlock; + } iio_device_get(indio_dev); @@ -194,6 +205,8 @@ int iio_event_getfd(struct iio_dev *indio_dev) kfifo_reset_out(&ev_int->det_events); } +unlock: + mutex_unlock(&indio_dev->mlock); return fd; } -- cgit v1.2.3