Adds a new per-device sysfs attribute "clockid" to allow userspace to select a
particular POSIX clock for buffered samples and events timestamping.
When read, the attribute file returns a stringifi'ed clockid_t matching the
currently selected clock.
Writing a stringifi'ed clockid_t to the attribute file will select the
corresponding clock for the device.
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 <gregor.boirie@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-iio | 7 +++
Documentation/DocBook/iio.tmpl | 2 +-
drivers/iio/iio_core.h | 3 +
drivers/iio/industrialio-core.c | 107 ++++++++++++++++++++++++++++++--
drivers/iio/industrialio-event.c | 19 +++++-
drivers/iio/industrialio-trigger.c | 2 +-
include/linux/iio/iio.h | 10 +--
7 files changed, 134 insertions(+), 16 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 3c66248..4602006 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -32,6 +32,13 @@ Description:
Description of the physical chip / device for device X.
Typically a part number.
+What: /sys/bus/iio/devices/iio:deviceX/clockid
+KernelVersion: 4.5
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ Identifier (clockid_t) of current posix clock used to timestamp
+ buffered samples and events for device X.
+
What: /sys/bus/iio/devices/iio:deviceX/sampling_frequency
What: /sys/bus/iio/devices/iio:deviceX/buffer/sampling_frequency
What: /sys/bus/iio/devices/triggerX/sampling_frequency
diff --git a/Documentation/DocBook/iio.tmpl b/Documentation/DocBook/iio.tmpl
index f525bf5..df47dd4 100644
--- a/Documentation/DocBook/iio.tmpl
+++ b/Documentation/DocBook/iio.tmpl
@@ -594,7 +594,7 @@
irqreturn_t sensor_iio_pollfunc(int irq, void *p)
{
- pf->timestamp = iio_get_time_ns();
+ pf->timestamp = iio_get_time_ns((struct indio_dev*) p);
return IRQ_WAKE_THREAD;
}
diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
index 3598835..a07d2ec 100644
--- a/drivers/iio/iio_core.h
+++ b/drivers/iio/iio_core.h
@@ -79,4 +79,7 @@ void iio_device_unregister_eventset(struct iio_dev *indio_dev);
void iio_device_wakeup_eventset(struct iio_dev *indio_dev);
int iio_event_getfd(struct iio_dev *indio_dev);
+struct iio_event_interface;
+bool iio_event_enabled(const struct iio_event_interface* ev_int);
+
#endif
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 70cb7eb..97bdb95 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -174,6 +174,44 @@ ssize_t iio_read_const_attr(struct device *dev,
}
EXPORT_SYMBOL(iio_read_const_attr);
+/**
+ * iio_get_time_ns() - utility function to get a time stamp for events etc
+ * @indio_dev: device
+ */
+s64 iio_get_time_ns(const struct iio_dev* indio_dev)
+{
+ struct timespec tp;
+
+ switch (indio_dev->clock_id) {
+ case CLOCK_REALTIME:
+ ktime_get_real_ts(&tp);
+ break;
+ case CLOCK_MONOTONIC:
+ ktime_get_ts(&tp);
+ break;
+ case CLOCK_MONOTONIC_RAW:
+ getrawmonotonic(&tp);
+ break;
+ case CLOCK_REALTIME_COARSE:
+ tp = current_kernel_time();
+ break;
+ case CLOCK_MONOTONIC_COARSE:
+ tp = get_monotonic_coarse();
+ break;
+ case CLOCK_BOOTTIME:
+ get_monotonic_boottime(&tp);
+ break;
+ case CLOCK_TAI:
+ timekeeping_clocktai(&tp);
+ break;
+ default:
+ BUG();
+ }
+
+ return timespec_to_ns(&tp);
+}
+EXPORT_SYMBOL(iio_get_time_ns);
+
static int __init iio_init(void)
{
int ret;
@@ -904,11 +942,61 @@ static ssize_t iio_show_dev_name(struct device *dev,
static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
+static ssize_t iio_show_clockid(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ return sprintf(buf, "%d\n", indio_dev->clock_id);
+}
+
+static ssize_t iio_store_clockid(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ int ret;
+ int clk;
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ const struct iio_event_interface *ev_int = indio_dev->event_interface;
+
+ ret = kstrtoint(buf, 0, &clk);
+ if (ret < 0)
+ return ret;
+
+ switch (clk) {
+ case CLOCK_REALTIME:
+ case CLOCK_MONOTONIC:
+ case CLOCK_MONOTONIC_RAW:
+ case CLOCK_REALTIME_COARSE:
+ case CLOCK_MONOTONIC_COARSE:
+ case CLOCK_BOOTTIME:
+ case CLOCK_TAI:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ret = mutex_lock_interruptible(&indio_dev->mlock);
+ if (ret)
+ return ret;
+ if ((ev_int && iio_event_enabled(ev_int)) ||
+ iio_buffer_enabled(indio_dev)) {
+ mutex_unlock(&indio_dev->mlock);
+ return -EBUSY;
+ }
+ indio_dev->clock_id = clk;
+ mutex_unlock(&indio_dev->mlock);
+
+ return len;
+}
+
+static DEVICE_ATTR(clockid, S_IRUGO | S_IWUSR,
+ iio_show_clockid, iio_store_clockid);
+
static int iio_device_register_sysfs(struct iio_dev *indio_dev)
{
int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
struct iio_dev_attr *p;
- struct attribute **attr;
+ struct attribute **attr, *clk = NULL;
/* First count elements in any existing group */
if (indio_dev->info->attrs) {
@@ -923,16 +1011,25 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
*/
if (indio_dev->channels)
for (i = 0; i < indio_dev->num_channels; i++) {
- ret = iio_device_add_channel_sysfs(indio_dev,
- &indio_dev
- ->channels[i]);
+ const struct iio_chan_spec *chan =
+ &indio_dev->channels[i];
+
+ if (chan->type == IIO_TIMESTAMP)
+ clk = &dev_attr_clockid.attr;
+
+ ret = iio_device_add_channel_sysfs(indio_dev, chan);
if (ret < 0)
goto error_clear_attrs;
attrcount += ret;
}
+ if (indio_dev->event_interface)
+ clk = &dev_attr_clockid.attr;
+
if (indio_dev->name)
attrcount++;
+ if (clk)
+ attrcount++;
indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
sizeof(indio_dev->chan_attr_group.attrs[0]),
@@ -953,6 +1050,8 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
if (indio_dev->name)
indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
+ if (clk)
+ indio_dev->chan_attr_group.attrs[attrn++] = clk;
indio_dev->groups[indio_dev->groupcounter++] =
&indio_dev->chan_attr_group;
diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
index cae332b..9480404 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;
}
diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index ae2806a..cf93717 100644
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -251,7 +251,7 @@ static int iio_trigger_detach_poll_func(struct iio_trigger *trig,
irqreturn_t iio_pollfunc_store_time(int irq, void *p)
{
struct iio_poll_func *pf = p;
- pf->timestamp = iio_get_time_ns();
+ pf->timestamp = iio_get_time_ns(pf->indio_dev);
return IRQ_WAKE_THREAD;
}
EXPORT_SYMBOL(iio_pollfunc_store_time);
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index ce9e9c1..904a5b0 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -281,13 +281,7 @@ static inline bool iio_channel_has_info(const struct iio_chan_spec *chan,
}, \
}
-/**
- * iio_get_time_ns() - utility function to get a time stamp for events etc
- **/
-static inline s64 iio_get_time_ns(void)
-{
- return ktime_get_real_ns();
-}
+extern s64 iio_get_time_ns(const struct iio_dev*);
/* Device operating modes */
#define INDIO_DIRECT_MODE 0x01
@@ -466,6 +460,7 @@ struct iio_buffer_setup_ops {
* @chan_attr_group: [INTERN] group for all attrs in base directory
* @name: [DRIVER] name of the device.
* @info: [DRIVER] callbacks and constant info from driver
+ * @clock_id: [INTERN] timestamping clock posix identifier
* @info_exist_lock: [INTERN] lock to prevent use during removal
* @setup_ops: [DRIVER] callbacks to call before and after buffer
* enable/disable
@@ -506,6 +501,7 @@ struct iio_dev {
struct attribute_group chan_attr_group;
const char *name;
const struct iio_info *info;
+ clockid_t clock_id;
struct mutex info_exist_lock;
const struct iio_buffer_setup_ops *setup_ops;
struct cdev chrdev;
--
2.1.4
--
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