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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git
commit 24040250f5d6645b4b1c0165d8a52323c755c7f6
Author: Jiuzhu Dong <dongjiuz...@xiaomi.com>
AuthorDate: Tue Mar 22 15:46:02 2022 +0800
driver/sensor: support multi users to access device
1.Allow multi users to access the same sensor device simultaneously.
2.Get real state of sensor device by cmd SNIOC_GET_STATE for users.
3.Get update state since last read by poll without timeout for users.
4.Sensor device will be activated when first user open and will close when
last user closed.
5.When multi users to access device, driver always set the minimum
sampling interval and latency to the sensor device and allow
downsampled for users above the minimum sampling interval.
6.The circbuffer will overwrite old data when buffer is full, so if users
don't read data soon, data will be lost, and the oldest data in circbuffer
are returned to the users.
7.Always read the last data in the circbuffer as initial value for new
users when the sensor device has not yet generated new data.
8.when user uses poll, if subscription interval is satisfied, the POLLIN
events is returned for each users.
9.When new user generate or the state of sensor device changed, the POLLPRI
will notify to all users.
10.Support multi advertisers to subscribe their own data as loop test.
Signed-off-by: Jiuzhu Dong <dongjiuz...@xiaomi.com>
---
drivers/sensors/Kconfig | 7 -
drivers/sensors/sensor.c | 499 +++++++++++++++++++++++++++++------------
include/nuttx/sensors/ioctl.h | 9 +-
include/nuttx/sensors/sensor.h | 11 +
4 files changed, 372 insertions(+), 154 deletions(-)
diff --git a/drivers/sensors/Kconfig b/drivers/sensors/Kconfig
index d4d50e8d87..1f2fc138ac 100644
--- a/drivers/sensors/Kconfig
+++ b/drivers/sensors/Kconfig
@@ -12,13 +12,6 @@ menuconfig SENSORS
if SENSORS
-config SENSORS_NPOLLWAITERS
- int "Number of poll threads"
- default 2
- ---help---
- Maximum number of threads than can be waiting for POLL events.
- Default: 2
-
config USENSOR
bool "Usensor Device Support"
default n
diff --git a/drivers/sensors/sensor.c b/drivers/sensors/sensor.c
index 1dada70e8b..5576ec8fb1 100644
--- a/drivers/sensors/sensor.c
+++ b/drivers/sensors/sensor.c
@@ -34,6 +34,7 @@
#include <poll.h>
#include <fcntl.h>
+#include <nuttx/list.h>
#include <nuttx/kmalloc.h>
#include <nuttx/mm/circbuf.h>
#include <nuttx/sensors/sensor.h>
@@ -55,28 +56,48 @@
/* This structure describes sensor info */
-struct sensor_info
+struct sensor_info_s
{
uint8_t esize;
FAR char *name;
};
+/* This structure describes user info of sensor, the user may be
+ * advertiser or subscriber
+ */
+
+struct sensor_user_s
+{
+ /* The common info */
+
+ struct list_node node; /* Node of users list */
+ struct pollfd *fds; /* The poll structure of thread waiting events
*/
+ bool changed; /* This is used to indicate event happens and
need to
+ * asynchronous notify other users
+ */
+ sem_t buffersem; /* Wakeup user waiting for data in circular
buffer */
+
+ /* The subscriber info
+ * Support multi advertisers to subscribe their own data when they
+ * appear in dual role
+ */
+
+ size_t generation; /* Last generation subscriber has seen */
+ unsigned long interval; /* The interval for subscriber */
+ unsigned long latency; /* The bactch latency for subscriber */
+};
+
/* This structure describes the state of the upper half driver */
struct sensor_upperhalf_s
{
- /* poll structures of threads waiting for driver events. */
-
- FAR struct pollfd *fds[CONFIG_SENSORS_NPOLLWAITERS];
- FAR struct sensor_lowerhalf_s *lower; /* the handle of lower half driver */
+ FAR struct sensor_lowerhalf_s *lower; /* The handle of lower half driver */
+ struct sensor_state_s state; /* The state of sensor device */
struct circbuf_s buffer; /* The circular buffer of sensor
device */
uint8_t esize; /* The element size of circular
buffer */
- uint8_t crefs; /* Number of times the device has
been opened */
sem_t exclsem; /* Manages exclusive access to file
operations */
- sem_t buffersem; /* Wakeup user waiting for data in
circular buffer */
- bool enabled; /* The status of sensor enable or
disable */
- unsigned long interval; /* The sample interval for sensor, in
us */
- unsigned long latency; /* The batch latency for sensor, in
us */
+ size_t generation; /* The current generation count */
+ struct list_node userlist; /* List of users */
};
/****************************************************************************
@@ -102,7 +123,7 @@ static ssize_t sensor_push_event(FAR void *priv, FAR const
void *data,
* Private Data
****************************************************************************/
-static const struct sensor_info g_sensor_info[] =
+static const struct sensor_info_s g_sensor_info[] =
{
{0, NULL},
{sizeof(struct sensor_event_accel), "accel"},
@@ -157,32 +178,174 @@ static const struct file_operations g_sensor_fops =
* Private Functions
****************************************************************************/
-static void sensor_pollnotify(FAR struct sensor_upperhalf_s *upper,
- pollevent_t eventset)
+static bool sensor_in_range(size_t left, size_t value, size_t right)
{
- FAR struct pollfd *fd;
- int semcount;
- int i;
+ if (left < right)
+ {
+ return left <= value && value < right;
+ }
+ else
+ {
+ /* Maybe the data overflowed and a wraparound occurred */
+
+ return left <= value || value < right;
+ }
+}
+
+static bool sensor_is_updated(size_t generation, size_t ugeneration)
+{
+ return generation > ugeneration;
+}
+
+static int sensor_update_interval(FAR struct sensor_upperhalf_s *upper,
+ FAR struct sensor_user_s *user,
+ unsigned long interval)
+{
+ FAR struct sensor_lowerhalf_s *lower = upper->lower;
+ FAR struct sensor_user_s *tmp;
+ unsigned long min_interval = interval;
+ int ret = 0;
+
+ if (interval == user->interval)
+ {
+ return 0;
+ }
+
+ if (interval <= upper->state.min_interval)
+ {
+ goto update;
+ }
- for (i = 0; i < CONFIG_SENSORS_NPOLLWAITERS; i++)
+ list_for_every_entry(&upper->userlist, tmp, struct sensor_user_s, node)
{
- fd = upper->fds[i];
- if (fd)
+ if (tmp == user)
{
- fd->revents |= (fd->events & eventset);
+ continue;
+ }
- if (fd->revents != 0)
- {
- sninfo("Report events: %08" PRIx32 "\n", fd->revents);
+ if (min_interval > tmp->interval)
+ {
+ min_interval = tmp->interval;
+ }
+ }
- nxsem_get_value(fd->sem, &semcount);
- if (semcount < 1)
- {
- nxsem_post(fd->sem);
- }
- }
+update:
+ if (min_interval == upper->state.min_interval)
+ {
+ user->interval = interval;
+ return ret;
+ }
+
+ if (min_interval != ULONG_MAX && lower->ops->set_interval)
+ {
+ ret = lower->ops->set_interval(lower, &min_interval);
+ if (ret < 0)
+ {
+ return ret;
}
}
+
+ upper->state.min_interval = min_interval;
+ user->interval = interval;
+ sensor_pollnotify(upper, POLLPRI);
+ return ret;
+}
+
+static int sensor_update_latency(FAR struct sensor_upperhalf_s *upper,
+ FAR struct sensor_user_s *user,
+ unsigned long latency)
+{
+ FAR struct sensor_lowerhalf_s *lower = upper->lower;
+ FAR struct sensor_user_s *tmp;
+ unsigned long min_latency = latency;
+ int ret = 0;
+
+ if (upper->state.min_interval == 0)
+ {
+ return -EINVAL;
+ }
+
+ if (latency == user->latency)
+ {
+ return 0;
+ }
+
+ if (latency <= upper->state.min_latency)
+ {
+ goto update;
+ }
+
+ list_for_every_entry(&upper->userlist, tmp, struct sensor_user_s, node)
+ {
+ if (tmp == user)
+ {
+ continue;
+ }
+
+ if (min_latency > tmp->latency)
+ {
+ min_latency = tmp->latency;
+ }
+ }
+
+update:
+ if (min_latency == upper->state.min_latency)
+ {
+ user->latency = latency;
+ return ret;
+ }
+
+ if (min_latency != ULONG_MAX && lower->ops->batch)
+ {
+ ret = lower->ops->batch(lower, &min_latency);
+ if (ret < 0)
+ {
+ return ret;
+ }
+ }
+
+ upper->state.min_latency = min_latency;
+ user->latency = latency;
+ sensor_pollnotify(upper, POLLPRI);
+ return ret;
+}
+
+static void sensor_pollnotify_one(FAR struct sensor_user_s *user,
+ pollevent_t eventset)
+{
+ int semcount;
+
+ if (eventset == POLLPRI)
+ {
+ user->changed = true;
+ }
+
+ if (!user->fds)
+ {
+ return;
+ }
+
+ user->fds->revents |= (user->fds->events & eventset);
+ if (user->fds->revents != 0)
+ {
+ sninfo("Report events: %08" PRIx32 "\n", user->fds->revents);
+ nxsem_get_value(user->fds->sem, &semcount);
+ if (semcount < 1)
+ {
+ nxsem_post(user->fds->sem);
+ }
+ }
+}
+
+static void sensor_pollnotify(FAR struct sensor_upperhalf_s *upper,
+ pollevent_t eventset)
+{
+ FAR struct sensor_user_s *user;
+
+ list_for_every_entry(&upper->userlist, user, struct sensor_user_s, node)
+ {
+ sensor_pollnotify_one(user, eventset);
+ }
}
static int sensor_open(FAR struct file *filep)
@@ -190,7 +353,7 @@ static int sensor_open(FAR struct file *filep)
FAR struct inode *inode = filep->f_inode;
FAR struct sensor_upperhalf_s *upper = inode->i_private;
FAR struct sensor_lowerhalf_s *lower = upper->lower;
- uint8_t tmp;
+ FAR struct sensor_user_s *user;
int ret;
ret = nxsem_wait(&upper->exclsem);
@@ -199,17 +362,49 @@ static int sensor_open(FAR struct file *filep)
return ret;
}
- tmp = upper->crefs + 1;
- if (tmp == 0)
+ user = kmm_zalloc(sizeof(struct sensor_user_s));
+ if (user == NULL)
{
- /* More than 255 opens; uint8_t overflows to zero */
+ ret = -ENOMEM;
+ goto errout_with_sem;
+ }
- ret = -EMFILE;
- goto err;
+ if (filep->f_oflags & O_RDOK)
+ {
+ if (upper->state.nsubscribers == 0 && lower->ops->activate)
+ {
+ ret = lower->ops->activate(lower, true);
+ if (ret < 0)
+ {
+ goto errout_with_user;
+ }
+ }
+
+ upper->state.nsubscribers++;
+ }
+
+ if (filep->f_oflags & O_WROK)
+ {
+ upper->state.nadvertisers++;
}
- upper->crefs = tmp;
-err:
+ user->interval = ULONG_MAX;
+ user->latency = ULONG_MAX;
+ user->generation = upper->generation;
+ nxsem_init(&user->buffersem, 0, 0);
+ nxsem_set_protocol(&user->buffersem, SEM_PRIO_NONE);
+ list_add_tail(&upper->userlist, &user->node);
+
+ /* The new user generation, notify to other users */
+
+ sensor_pollnotify(upper, POLLPRI);
+
+ filep->f_priv = user;
+ goto errout_with_sem;
+
+errout_with_user:
+ kmm_free(user);
+errout_with_sem:
nxsem_post(&upper->exclsem);
return ret;
}
@@ -219,6 +414,7 @@ static int sensor_close(FAR struct file *filep)
FAR struct inode *inode = filep->f_inode;
FAR struct sensor_upperhalf_s *upper = inode->i_private;
FAR struct sensor_lowerhalf_s *lower = upper->lower;
+ FAR struct sensor_user_s *user = filep->f_priv;
int ret;
ret = nxsem_wait(&upper->exclsem);
@@ -227,18 +423,31 @@ static int sensor_close(FAR struct file *filep)
return ret;
}
- if (--upper->crefs <= 0 && upper->enabled)
+ if (filep->f_oflags & O_RDOK)
{
- ret = lower->ops->activate ?
- lower->ops->activate(lower, false) : -ENOTSUP;
- if (ret >= 0)
+ upper->state.nsubscribers--;
+ if (upper->state.nsubscribers == 0 && lower->ops->activate)
{
- upper->enabled = false;
- circbuf_uninit(&upper->buffer);
+ lower->ops->activate(lower, false);
}
}
+ if (filep->f_oflags & O_WROK)
+ {
+ upper->state.nadvertisers--;
+ }
+
+ list_delete(&user->node);
+ sensor_update_latency(upper, user, ULONG_MAX);
+ sensor_update_interval(upper, user, ULONG_MAX);
+ nxsem_destroy(&user->buffersem);
+
+ /* The user is closed, notify to other users */
+
+ sensor_pollnotify(upper, POLLPRI);
nxsem_post(&upper->exclsem);
+
+ kmm_free(user);
return ret;
}
@@ -248,7 +457,9 @@ static ssize_t sensor_read(FAR struct file *filep, FAR char
*buffer,
FAR struct inode *inode = filep->f_inode;
FAR struct sensor_upperhalf_s *upper = inode->i_private;
FAR struct sensor_lowerhalf_s *lower = upper->lower;
+ FAR struct sensor_user_s *user = filep->f_priv;
ssize_t ret;
+ size_t nums;
if (!buffer || !len)
{
@@ -266,7 +477,7 @@ static ssize_t sensor_read(FAR struct file *filep, FAR char
*buffer,
if (!(filep->f_oflags & O_NONBLOCK))
{
nxsem_post(&upper->exclsem);
- ret = nxsem_wait_uninterruptible(&upper->buffersem);
+ ret = nxsem_wait_uninterruptible(&user->buffersem);
if (ret < 0)
{
return ret;
@@ -278,7 +489,7 @@ static ssize_t sensor_read(FAR struct file *filep, FAR char
*buffer,
return ret;
}
}
- else if (!upper->enabled)
+ else if (!upper->state.nsubscribers)
{
ret = -EAGAIN;
goto out;
@@ -304,7 +515,7 @@ static ssize_t sensor_read(FAR struct file *filep, FAR char
*buffer,
else
{
nxsem_post(&upper->exclsem);
- ret = nxsem_wait_uninterruptible(&upper->buffersem);
+ ret = nxsem_wait_uninterruptible(&user->buffersem);
if (ret < 0)
{
return ret;
@@ -318,7 +529,37 @@ static ssize_t sensor_read(FAR struct file *filep, FAR
char *buffer,
}
}
- ret = circbuf_read(&upper->buffer, buffer, len);
+ /* Always read the last data in the circbuffer as initial value
+ * for new users when the sensor device has not yet generated
+ * new data.
+ */
+
+ if (user->generation == upper->generation)
+ {
+ user->generation--;
+ }
+
+ /* If user's generation isn't within circbuffer range, the
+ * oldest data in circbuffer are returned to the users.
+ */
+
+ else if (!sensor_in_range(upper->generation - lower->buffer_number,
+ user->generation, upper->generation))
+
+ {
+ user->generation = upper->generation - lower->buffer_number;
+ }
+
+ nums = upper->generation - user->generation;
+ if (len < nums * upper->esize)
+ {
+ nums = len / upper->esize;
+ }
+
+ len = nums * upper->esize;
+ ret = circbuf_peekat(&upper->buffer, user->generation * upper->esize,
+ buffer, len);
+ user->generation += nums;
}
out:
@@ -340,6 +581,7 @@ static int sensor_ioctl(FAR struct file *filep, int cmd,
unsigned long arg)
FAR struct inode *inode = filep->f_inode;
FAR struct sensor_upperhalf_s *upper = inode->i_private;
FAR struct sensor_lowerhalf_s *lower = upper->lower;
+ FAR struct sensor_user_s *user = filep->f_priv;
int ret;
sninfo("cmd=%x arg=%08lx\n", cmd, arg);
@@ -352,72 +594,23 @@ static int sensor_ioctl(FAR struct file *filep, int cmd,
unsigned long arg)
switch (cmd)
{
- case SNIOC_ACTIVATE:
+ case SNIOC_GET_STATE:
{
- if (upper->enabled == !!arg)
- {
- break;
- }
-
- ret = lower->ops->activate ?
- lower->ops->activate(lower, !!arg) : -ENOTSUP;
- if (ret >= 0)
- {
- upper->enabled = !!arg;
- if (!upper->enabled)
- {
- upper->interval = 0;
- upper->latency = 0;
- }
- }
+ memcpy((FAR void *)(uintptr_t)arg,
+ &upper->state, sizeof(upper->state));
+ user->changed = false;
}
break;
case SNIOC_SET_INTERVAL:
{
- if (lower->ops->set_interval == NULL)
- {
- ret = -ENOTSUP;
- break;
- }
-
- if (upper->interval == arg)
- {
- break;
- }
-
- ret = lower->ops->set_interval(lower, &arg);
- if (ret >= 0)
- {
- upper->interval = arg;
- }
+ ret = sensor_update_interval(upper, user, arg);
}
break;
case SNIOC_BATCH:
{
- if (lower->ops->batch == NULL)
- {
- ret = -ENOTSUP;
- break;
- }
-
- if (upper->interval == 0)
- {
- ret = -EINVAL;
- break;
- }
-
- if (upper->latency == arg)
- {
- break;
- }
-
- ret = lower->ops->batch(lower, &arg);
- if (ret >= 0)
- {
- upper->latency = arg;
- }
+ ret = sensor_update_latency(upper, user, arg);
}
break;
@@ -467,7 +660,14 @@ static int sensor_ioctl(FAR struct file *filep, int cmd,
unsigned long arg)
{
if (!circbuf_is_init(&upper->buffer))
{
- lower->buffer_number = arg;
+ if (arg >= lower->buffer_number)
+ {
+ lower->buffer_number = arg;
+ }
+ else
+ {
+ ret = -ERANGE;
+ }
}
else
{
@@ -497,15 +697,15 @@ static int sensor_ioctl(FAR struct file *filep, int cmd,
unsigned long arg)
}
static int sensor_poll(FAR struct file *filep,
- struct pollfd *fds, bool setup)
+ FAR struct pollfd *fds, bool setup)
{
FAR struct inode *inode = filep->f_inode;
FAR struct sensor_upperhalf_s *upper = inode->i_private;
FAR struct sensor_lowerhalf_s *lower = upper->lower;
+ FAR struct sensor_user_s *user = filep->f_priv;
pollevent_t eventset = 0;
int semcount;
int ret;
- int i;
ret = nxsem_wait(&upper->exclsem);
if (ret < 0)
@@ -515,24 +715,16 @@ static int sensor_poll(FAR struct file *filep,
if (setup)
{
- for (i = 0; i < CONFIG_SENSORS_NPOLLWAITERS; i++)
- {
- if (NULL == upper->fds[i])
- {
- upper->fds[i] = fds;
- fds->priv = &upper->fds[i];
- break;
- }
- }
-
/* Don't have enough space to store fds */
- if (i == CONFIG_SENSORS_NPOLLWAITERS)
+ if (user->fds)
{
ret = -ENOSPC;
goto errout;
}
+ user->fds = fds;
+ fds->priv = filep;
if (lower->ops->fetch)
{
/* Always return POLLIN for fetch data directly(non-block) */
@@ -543,34 +735,32 @@ static int sensor_poll(FAR struct file *filep,
}
else
{
- nxsem_get_value(&upper->buffersem, &semcount);
+ nxsem_get_value(&user->buffersem, &semcount);
if (semcount > 0)
{
eventset |= (fds->events & POLLIN);
}
}
}
- else if (!circbuf_is_empty(&upper->buffer))
+ else if (sensor_is_updated(upper->generation, user->generation))
{
eventset |= (fds->events & POLLIN);
}
+ if (user->changed)
+ {
+ eventset |= (fds->events & POLLPRI);
+ }
+
if (eventset)
{
- sensor_pollnotify(upper, eventset);
+ sensor_pollnotify_one(user, eventset);
}
}
- else if (fds->priv != NULL)
+ else
{
- for (i = 0; i < CONFIG_SENSORS_NPOLLWAITERS; i++)
- {
- if (fds == upper->fds[i])
- {
- upper->fds[i] = NULL;
- fds->priv = NULL;
- break;
- }
- }
+ user->fds = NULL;
+ fds->priv = NULL;
}
errout:
@@ -583,10 +773,13 @@ static ssize_t sensor_push_event(FAR void *priv, FAR
const void *data,
{
FAR struct sensor_upperhalf_s *upper = priv;
FAR struct sensor_lowerhalf_s *lower = upper->lower;
+ FAR struct sensor_user_s *user;
+ size_t envcount;
int semcount;
int ret;
- if (!bytes)
+ envcount = bytes / upper->esize;
+ if (!envcount || bytes != envcount * upper->esize)
{
return -EINVAL;
}
@@ -611,11 +804,19 @@ static ssize_t sensor_push_event(FAR void *priv, FAR
const void *data,
}
circbuf_overwrite(&upper->buffer, data, bytes);
- sensor_pollnotify(upper, POLLIN);
- nxsem_get_value(&upper->buffersem, &semcount);
- if (semcount < 1)
+ upper->generation += envcount;
+ list_for_every_entry(&upper->userlist, user, struct sensor_user_s, node)
{
- nxsem_post(&upper->buffersem);
+ if (sensor_is_updated(upper->generation, user->generation))
+ {
+ nxsem_get_value(&user->buffersem, &semcount);
+ if (semcount < 1)
+ {
+ nxsem_post(&user->buffersem);
+ }
+
+ sensor_pollnotify_one(user, POLLIN);
+ }
}
nxsem_post(&upper->exclsem);
@@ -625,6 +826,7 @@ static ssize_t sensor_push_event(FAR void *priv, FAR const
void *data,
static void sensor_notify_event(FAR void *priv)
{
FAR struct sensor_upperhalf_s *upper = priv;
+ FAR struct sensor_user_s *user;
int semcount;
if (nxsem_wait(&upper->exclsem) < 0)
@@ -632,11 +834,15 @@ static void sensor_notify_event(FAR void *priv)
return;
}
- sensor_pollnotify(upper, POLLIN);
- nxsem_get_value(&upper->buffersem, &semcount);
- if (semcount < 1)
+ list_for_every_entry(&upper->userlist, user, struct sensor_user_s, node)
{
- nxsem_post(&upper->buffersem);
+ nxsem_get_value(&user->buffersem, &semcount);
+ if (semcount < 1)
+ {
+ nxsem_post(&user->buffersem);
+ }
+
+ sensor_pollnotify_one(user, POLLIN);
}
nxsem_post(&upper->exclsem);
@@ -737,10 +943,15 @@ int sensor_custom_register(FAR struct sensor_lowerhalf_s
*lower,
upper->lower = lower;
upper->esize = esize;
- nxsem_init(&upper->exclsem, 0, 1);
- nxsem_init(&upper->buffersem, 0, 0);
+ list_initialize(&upper->userlist);
+ upper->state.min_interval = ULONG_MAX;
+ upper->state.min_latency = ULONG_MAX;
+ if (lower->ops->activate)
+ {
+ upper->state.nadvertisers = 1;
+ }
- nxsem_set_protocol(&upper->buffersem, SEM_PRIO_NONE);
+ nxsem_init(&upper->exclsem, 0, 1);
/* Bind the lower half data structure member */
@@ -772,7 +983,6 @@ int sensor_custom_register(FAR struct sensor_lowerhalf_s
*lower,
drv_err:
nxsem_destroy(&upper->exclsem);
- nxsem_destroy(&upper->buffersem);
kmm_free(upper);
@@ -832,7 +1042,10 @@ void sensor_custom_unregister(FAR struct
sensor_lowerhalf_s *lower,
unregister_driver(path);
nxsem_destroy(&upper->exclsem);
- nxsem_destroy(&upper->buffersem);
+ if (circbuf_is_init(&upper->buffer))
+ {
+ circbuf_uninit(&upper->buffer);
+ }
kmm_free(upper);
}
diff --git a/include/nuttx/sensors/ioctl.h b/include/nuttx/sensors/ioctl.h
index 210708f38d..d2cfff813e 100644
--- a/include/nuttx/sensors/ioctl.h
+++ b/include/nuttx/sensors/ioctl.h
@@ -234,12 +234,13 @@
#define SNIOC_READROMCODE _SNIOC(0x0067) /* Arg: uint64_t* pointer */
#define SNIOC_SETALARM _SNIOC(0x0068) /* Arg: struct
ds18b20_alarm_s* */
-/* Command: SNIOC_ACTIVATE
- * Description: Enable or disable sensor
- * Argument: true or false.
+/* Command: SNIOC_GET_STATE
+ * Description: Get state for all subscribers, include min_interval,
+ * min_latency and the number of subscribers.
+ * Argument: This is the state pointer
*/
-#define SNIOC_ACTIVATE _SNIOC(0x0080)
+#define SNIOC_GET_STATE _SNIOC(0x0080)
/* Command: SNIOC_SET_INTERVAL
* Description: Set interval between samples
diff --git a/include/nuttx/sensors/sensor.h b/include/nuttx/sensors/sensor.h
index 6c694be01f..9336ad5028 100644
--- a/include/nuttx/sensors/sensor.h
+++ b/include/nuttx/sensors/sensor.h
@@ -874,6 +874,17 @@ struct sensor_lowerhalf_s
FAR void *priv;
};
+/* This structure describes the state for the sensor device */
+
+struct sensor_state_s
+{
+ unsigned long min_interval; /* The minimum subscription interval for
sensor, in us */
+ unsigned long min_latency; /* The minimum batch latency for sensor, in us
*/
+ unsigned long nsubscribers; /* The number of subcribers, if subsrciber
exists,
+ * the sensor deivce is enabled */
+ unsigned long nadvertisers; /* The number of advertisers */
+};
+
/* This structure describes the register info for the user sensor */
#ifdef CONFIG_USENSOR
