battery_monitor:add poll support

Signed-off-by: anjiahao <anjiahao@xiaomi.com>

drivers/power/battery_monitor.c

@@ -28,10 +28,14 @@
 
 #include <stdbool.h>
 #include <errno.h>
+#include <string.h>
 #include <debug.h>
+#include <poll.h>
+#include <fcntl.h>
 
 #include <nuttx/semaphore.h>
 #include <nuttx/fs/fs.h>
+#include <nuttx/kmalloc.h>
 #include <nuttx/power/battery_monitor.h>
 #include <nuttx/power/battery_ioctl.h>
 
@@ -47,9 +51,18 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Private
+ * Private type
  ****************************************************************************/
 
+struct battery_monitor_priv_s
+{
+  struct list_node  node;
+  sem_t             lock;
+  sem_t             wait;
+  uint32_t          mask;
+  FAR struct pollfd *fds;
+};
+
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
@@ -59,11 +72,13 @@
 static int     bat_monitor_open(FAR struct file *filep);
 static int     bat_monitor_close(FAR struct file *filep);
 static ssize_t bat_monitor_read(FAR struct file *filep, FAR char *buffer,
-                 size_t buflen);
+                                size_t buflen);
 static ssize_t bat_monitor_write(FAR struct file *filep,
-                 FAR const char *buffer, size_t buflen);
+                                 FAR const char *buffer, size_t buflen);
 static int     bat_monitor_ioctl(FAR struct file *filep, int cmd,
-                 unsigned long arg);
+                                 unsigned long arg);
+static int     bat_monitor_poll(FAR struct file *filep,
+                                FAR struct pollfd *fds, bool setup);
 
 /****************************************************************************
  * Private Data
@@ -77,13 +92,48 @@ static const struct file_operations g_batteryops =
   bat_monitor_write,
   NULL,
   bat_monitor_ioctl,
-  NULL
+  bat_monitor_poll
 };
 
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
 
+static int battery_monitor_notify(FAR struct battery_monitor_priv_s *priv,
+                                   uint32_t mask)
+{
+  FAR struct pollfd *fd = priv->fds;
+  int semcnt;
+  int ret;
+
+  ret = nxsem_wait_uninterruptible(&priv->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  priv->mask |= mask;
+  if (priv->mask)
+    {
+      fd->revents |= POLLIN;
+      nxsem_get_value(fd->sem, &semcnt);
+      if (semcnt < 1)
+        {
+          nxsem_post(fd->sem);
+        }
+
+      nxsem_get_value(&priv->wait, &semcnt);
+      if (semcnt < 1)
+        {
+          nxsem_post(&priv->wait);
+        }
+    }
+
+  nxsem_post(&priv->lock);
+
+  return OK;
+}
+
 /****************************************************************************
  * Name: bat_monitor_open
  *
@@ -94,7 +144,31 @@ static const struct file_operations g_batteryops =
 
 static int bat_monitor_open(FAR struct file *filep)
 {
-  return OK;
+  FAR struct battery_monitor_priv_s *priv;
+  FAR struct battery_monitor_dev_s *dev = filep->f_inode->i_private;
+  int ret;
+
+  priv = kmm_zalloc(sizeof(*priv));
+  if (priv == NULL)
+    {
+      return -ENOMEM;
+    }
+
+  ret = nxsem_wait(&dev->batsem);
+  if (ret < 0)
+    {
+      kmm_free(priv);
+      return ret;
+    }
+
+  nxsem_init(&priv->lock, 0, 1);
+  nxsem_init(&priv->wait, 0, 0);
+  nxsem_set_protocol(&priv->wait, SEM_PRIO_NONE);
+  list_add_tail(&dev->flist, &priv->node);
+  nxsem_post(&dev->batsem);
+  filep->f_priv = priv;
+
+  return ret;
 }
 
 /****************************************************************************
@@ -107,6 +181,22 @@ static int bat_monitor_open(FAR struct file *filep)
 
 static int bat_monitor_close(FAR struct file *filep)
 {
+  FAR struct battery_monitor_priv_s *priv = filep->f_priv;
+  FAR struct battery_monitor_dev_s *dev = filep->f_inode->i_private;
+  int ret;
+
+  ret = nxsem_wait(&dev->batsem);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  list_delete(&priv->node);
+  nxsem_post(&dev->batsem);
+  nxsem_destroy(&priv->lock);
+  nxsem_destroy(&priv->wait);
+  kmm_free(priv);
+
   return OK;
 }
 
@@ -117,9 +207,46 @@ static int bat_monitor_close(FAR struct file *filep)
 static ssize_t bat_monitor_read(FAR struct file *filep, FAR char *buffer,
                                 size_t buflen)
 {
-  /* Return nothing read */
+  FAR struct battery_monitor_priv_s *priv = filep->f_priv;
+  int ret;
 
-  return 0;
+  if (buflen < sizeof(priv->mask))
+    {
+      return -EINVAL;
+    }
+
+  ret = nxsem_wait(&priv->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  while (priv->mask == 0)
+    {
+      nxsem_post(&priv->lock);
+      if (filep->f_oflags & O_NONBLOCK)
+        {
+          return -EAGAIN;
+        }
+
+      ret = nxsem_wait(&priv->wait);
+      if (ret < 0)
+        {
+          return ret;
+        }
+
+      ret = nxsem_wait(&priv->lock);
+      if (ret < 0)
+        {
+          return ret;
+        }
+    }
+
+  memcpy(buffer, &priv->mask, sizeof(priv->mask));
+  priv->mask = 0;
+
+  nxsem_post(&priv->lock);
+  return sizeof(priv->mask);
 }
 
 /****************************************************************************
@@ -310,10 +437,76 @@ static int bat_monitor_ioctl(FAR struct file *filep, int cmd,
   return ret;
 }
 
+/****************************************************************************
+ * Name: bat_monitor_poll
+ ****************************************************************************/
+
+static ssize_t bat_monitor_poll(FAR struct file *filep,
+                                struct pollfd *fds, bool setup)
+{
+  FAR struct battery_monitor_priv_s *priv = filep->f_priv;
+  int ret;
+
+  ret = nxsem_wait(&priv->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  if (setup)
+    {
+      if (priv->fds == NULL)
+        {
+          priv->fds = fds;
+          fds->priv = &priv->fds;
+        }
+      else
+        {
+          ret = -EBUSY;
+        }
+    }
+  else if (fds->priv != NULL)
+    {
+      priv->fds = NULL;
+      fds->priv = NULL;
+    }
+
+  nxsem_post(&priv->lock);
+
+  if (setup)
+    {
+      battery_monitor_notify(priv, 0);
+    }
+
+  return ret;
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
 
+int battery_monitor_changed(FAR struct battery_monitor_dev_s *dev,
+                             uint32_t mask)
+{
+  FAR struct battery_monitor_priv_s *priv;
+  int ret;
+
+  ret = nxsem_wait_uninterruptible(&dev->batsem);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  list_for_every_entry(&dev->flist, priv,
+                       struct battery_monitor_priv_s, node)
+    {
+      battery_monitor_notify(priv, mask);
+    }
+
+  nxsem_post(&dev->batsem);
+  return OK;
+}
+
 /****************************************************************************
  * Name: battery_monitor_register
  *
@@ -336,9 +529,10 @@ int battery_monitor_register(FAR const char *devpath,
 {
   int ret;
 
-  /* Initialize the semaphore */
+  /* Initialize the semaphore and the list */
 
   nxsem_init(&dev->batsem, 0, 1);
+  list_initialize(&dev->flist);
 
   /* Register the character driver */
 

include/nuttx/power/battery_ioctl.h

@@ -69,7 +69,9 @@
 #define BATTERY_VOLTAGE_CHANGED         (1U << 3)
 #define BATTERY_CURRENT_CHANGED         (1U << 4)
 #define BATTERY_CAPACITY_CHANGED        (1U << 5)
-#define BATTERY_TEMPERATURE_CHANGED     (1U << 6)
+#define BATTERY_CELLVOLTAGE_CHANGED     (1U << 6)
+#define BATTERY_TEMPERATURE_CHANGED     (1U << 7)
+#define BATTERY_COULOMBS_CHANGED        (1U << 8)
 
 /****************************************************************************
  * Public Types

include/nuttx/power/battery_monitor.h

@@ -28,6 +28,7 @@
 
 #include <nuttx/config.h>
 #include <nuttx/fs/ioctl.h>
+#include <nuttx/list.h>
 
 #include <stdbool.h>
 #include <stdint.h>
@@ -296,6 +297,8 @@ struct battery_monitor_dev_s
   FAR const struct battery_monitor_operations_s *ops; /* Battery operations */
   sem_t batsem;                                       /* Enforce mutually exclusive access */
 
+  struct list_node flist;
+
   /* Data fields specific to the lower-half driver may follow */
 };
 
@@ -317,6 +320,13 @@ extern "C"
  * Public Function Prototypes
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: battery_monitor_changed
+ ****************************************************************************/
+
+int battery_monitor_changed(FAR struct battery_monitor_dev_s *dev,
+                            uint32_t mask);
+
 /****************************************************************************
  * Name: battery_monitor_register
  *