drivers/gpio: add poll function for gpio device

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>

drivers/ioexpander/gpio.c

@@ -32,6 +32,7 @@
 #include <debug.h>
 #include <errno.h>
 #include <unistd.h>
+#include <poll.h>
 
 #include <nuttx/fs/fs.h>
 #include <nuttx/spinlock.h>
@@ -44,6 +45,7 @@
  ****************************************************************************/
 
 static int     gpio_handler(FAR struct gpio_dev_s *dev, uint8_t pin);
+static int     gpio_open(FAR struct file *filep);
 static ssize_t gpio_read(FAR struct file *filep, FAR char *buffer,
                          size_t buflen);
 static ssize_t gpio_write(FAR struct file *filep, FAR const char *buffer,
@@ -51,6 +53,8 @@ static ssize_t gpio_write(FAR struct file *filep, FAR const char *buffer,
 static off_t   gpio_seek(FAR struct file *filep, off_t offset, int whence);
 static int     gpio_ioctl(FAR struct file *filep, int cmd,
                           unsigned long arg);
+static int     gpio_poll(FAR struct file *filep,
+                         FAR struct pollfd *fds, bool setup);
 
 /****************************************************************************
  * Private Data
@@ -58,12 +62,15 @@ static int     gpio_ioctl(FAR struct file *filep, int cmd,
 
 static const struct file_operations g_gpio_drvrops =
 {
-  NULL,        /* open */
+  gpio_open,   /* open */
   NULL,        /* close */
   gpio_read,   /* read */
   gpio_write,  /* write */
   gpio_seek,   /* seek */
   gpio_ioctl,  /* ioctl */
+  NULL,        /* mmap */
+  NULL,        /* truncate */
+  gpio_poll,   /* poll */
 };
 
 /****************************************************************************
@@ -84,6 +91,10 @@ static int gpio_handler(FAR struct gpio_dev_s *dev, uint8_t pin)
 
   DEBUGASSERT(dev != NULL);
 
+  dev->int_count++;
+
+  poll_notify(dev->fds, CONFIG_DEV_GPIO_NSIGNALS, POLLIN);
+
   for (i = 0; i < CONFIG_DEV_GPIO_NSIGNALS; i++)
     {
       FAR struct gpio_signal_s *signal = &dev->gp_signals[i];
@@ -100,6 +111,27 @@ static int gpio_handler(FAR struct gpio_dev_s *dev, uint8_t pin)
   return OK;
 }
 
+/****************************************************************************
+ * Name: gpio_open
+ *
+ * Description:
+ *   Standard character driver open method.
+ *
+ ****************************************************************************/
+
+static int gpio_open(FAR struct file *filep)
+{
+  FAR struct inode *inode;
+  FAR struct gpio_dev_s *dev;
+
+  inode = filep->f_inode;
+  DEBUGASSERT(inode->i_private != NULL);
+  dev = inode->i_private;
+
+  filep->f_priv = (FAR void *)dev->int_count;
+  return OK;
+}
+
 /****************************************************************************
  * Name: gpio_read
  *
@@ -138,7 +170,9 @@ static ssize_t gpio_read(FAR struct file *filep, FAR char *buffer,
       return 0;
     }
 
-  /* Read the GPIO value */
+  /* Update interrupt count and read the GPIO value */
+
+  filep->f_priv = (FAR void *)dev->int_count;
 
   ret = dev->gp_ops->go_read(dev, (FAR bool *)&buffer[0]);
   if (ret < 0)
@@ -272,9 +306,9 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
   FAR struct gpio_dev_s *dev;
   irqstate_t flags;
   pid_t pid;
-  int ret;
+  int ret = OK;
   int i;
-  int j = 0;
+  int j;
 
   inode = filep->f_inode;
   DEBUGASSERT(inode->i_private != NULL);
@@ -313,6 +347,8 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
           FAR bool *ptr = (FAR bool *)((uintptr_t)arg);
           DEBUGASSERT(ptr != NULL);
 
+          filep->f_priv = (FAR void *)dev->int_count;
+
           DEBUGASSERT(dev->gp_ops->go_read != NULL);
           ret = dev->gp_ops->go_read(dev, ptr);
           DEBUGASSERT(ret < 0 || *ptr == 0 || *ptr == 1);
@@ -331,7 +367,6 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
           DEBUGASSERT(ptr != NULL);
 
           *ptr = (enum gpio_pintype_e)dev->gp_pintype;
-          ret = OK;
         }
         break;
 
@@ -345,44 +380,52 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
        */
 
       case GPIOC_REGISTER:
-        if (arg && dev->gp_pintype >= GPIO_INTERRUPT_PIN)
+        if (dev->gp_pintype >= GPIO_INTERRUPT_PIN)
           {
-            pid = nxsched_getpid();
+            flags = enter_critical_section();
-            flags = spin_lock_irqsave(NULL);
+            if (arg)
-            for (i = 0; i < CONFIG_DEV_GPIO_NSIGNALS; i++)
               {
-                FAR struct gpio_signal_s *signal = &dev->gp_signals[i];
+                pid = nxsched_getpid();
-
+                for (i = 0; i < CONFIG_DEV_GPIO_NSIGNALS; i++)
-                if (signal->gp_pid == 0 || signal->gp_pid == pid)
                   {
-                    memcpy(&signal->gp_event, (FAR void *)arg,
+                    FAR struct gpio_signal_s *signal = &dev->gp_signals[i];
-                           sizeof(signal->gp_event));
+
-                    signal->gp_pid = pid;
+                    if (signal->gp_pid == 0 || signal->gp_pid == pid)
-                    ret = OK;
+                      {
+                        memcpy(&signal->gp_event, (FAR void *)arg,
+                               sizeof(signal->gp_event));
+                        signal->gp_pid = pid;
+                        break;
+                      }
+                  }
+
+                if (i == CONFIG_DEV_GPIO_NSIGNALS)
+                  {
+                    leave_critical_section(flags);
+                    ret = -EBUSY;
                     break;
                   }
               }
 
-            spin_unlock_irqrestore(NULL, flags);
+            if (dev->register_count++ > 0)
-
-            if (i == 0)
               {
-                /* Register our handler */
+                leave_critical_section(flags);
-
+                break;
-                DEBUGASSERT(dev->gp_ops->go_attach != NULL);
-                ret = dev->gp_ops->go_attach(dev,
-                                             (pin_interrupt_t)gpio_handler);
-                if (ret >= 0)
-                  {
-                    /* Enable pin interrupts */
-
-                    DEBUGASSERT(dev->gp_ops->go_enable != NULL);
-                    ret = dev->gp_ops->go_enable(dev, true);
-                  }
               }
-            else if (i == CONFIG_DEV_GPIO_NSIGNALS)
+
+            leave_critical_section(flags);
+
+            /* Register our handler */
+
+            DEBUGASSERT(dev->gp_ops->go_attach != NULL);
+            ret = dev->gp_ops->go_attach(dev,
+                                         (pin_interrupt_t)gpio_handler);
+            if (ret >= 0)
               {
-                ret = -EBUSY;
+                /* Enable pin interrupts */
+
+                DEBUGASSERT(dev->gp_ops->go_enable != NULL);
+                ret = dev->gp_ops->go_enable(dev, true);
               }
           }
         else
@@ -400,7 +443,7 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
         if (dev->gp_pintype >= GPIO_INTERRUPT_PIN)
           {
             pid = nxsched_getpid();
-            flags = spin_lock_irqsave(NULL);
+            flags = enter_critical_section();
             for (i = 0; i < CONFIG_DEV_GPIO_NSIGNALS; i++)
               {
                 if (pid == dev->gp_signals[i].gp_pid)
@@ -421,30 +464,28 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
 
                     dev->gp_signals[j].gp_pid = 0;
                     nxsig_cancel_notification(&dev->gp_signals[j].gp_work);
-                    ret = OK;
                     break;
                   }
-                }
-
-            spin_unlock_irqrestore(NULL, flags);
-
-            if (i == 0 && j == 0)
-              {
-                /* Make sure that the pin interrupt is disabled */
-
-                DEBUGASSERT(dev->gp_ops->go_enable != NULL);
-                ret = dev->gp_ops->go_enable(dev, false);
-                if (ret >= 0)
-                  {
-                    /* Detach the handler */
-
-                    DEBUGASSERT(dev->gp_ops->go_attach != NULL);
-                    ret = dev->gp_ops->go_attach(dev, NULL);
-                  }
               }
-            else if (i == CONFIG_DEV_GPIO_NSIGNALS)
+
+            if (--dev->register_count > 0)
               {
-                ret = -EINVAL;
+                leave_critical_section(flags);
+                break;
+              }
+
+            leave_critical_section(flags);
+
+            /* Make sure that the pin interrupt is disabled */
+
+            DEBUGASSERT(dev->gp_ops->go_enable != NULL);
+            ret = dev->gp_ops->go_enable(dev, false);
+            if (ret >= 0)
+              {
+                /* Detach the handler */
+
+                DEBUGASSERT(dev->gp_ops->go_attach != NULL);
+                ret = dev->gp_ops->go_attach(dev, NULL);
               }
           }
         else
@@ -476,7 +517,6 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
             {
               /* Pintype remains the same, no need to change anything */
 
-              ret = OK;
               break;
             }
 
@@ -532,6 +572,76 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
   return ret;
 }
 
+/****************************************************************************
+ * Name: gpio_poll
+ *
+ * Description:
+ *   Poll method for gpio device.
+ *
+ ****************************************************************************/
+
+static int gpio_poll(FAR struct file *filep,
+                     FAR struct pollfd *fds, bool setup)
+{
+  FAR struct inode *inode = filep->f_inode;
+  FAR struct gpio_dev_s *dev = inode->i_private;
+  irqstate_t flags;
+  int ret = OK;
+  int i;
+
+  /* Are we setting up the poll?  Or tearing it down? */
+
+  flags = enter_critical_section();
+  if (setup)
+    {
+      /* This is a request to set up the poll.  Find an available
+       * slot for the poll structure reference
+       */
+
+      for (i = 0; i < CONFIG_DEV_GPIO_NSIGNALS; i++)
+        {
+          /* Find an available slot */
+
+          if (dev->fds[i] == NULL)
+            {
+              /* Bind the poll structure and this slot */
+
+              dev->fds[i] = fds;
+              fds->priv   = &dev->fds[i];
+
+              /* Report if a event is pending */
+
+              if (dev->int_count != (uintptr_t)(filep->f_priv))
+                {
+                  poll_notify(&fds, 1, POLLIN);
+                }
+
+              break;
+            }
+        }
+
+      if (i >= CONFIG_DEV_GPIO_NSIGNALS)
+        {
+          fds->priv = NULL;
+          ret       = -EBUSY;
+        }
+    }
+  else if (fds->priv != NULL)
+    {
+      /* This is a request to tear down the poll. */
+
+      FAR struct pollfd **slot = (FAR struct pollfd **)fds->priv;
+
+      /* Remove all memory of the poll setup */
+
+      *slot     = NULL;
+      fds->priv = NULL;
+    }
+
+  leave_critical_section(flags);
+  return ret;
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/

include/nuttx/ioexpander/gpio.h

@@ -152,6 +152,14 @@ struct gpio_dev_s
 
   uint8_t gp_pintype;  /* See enum gpio_pintype_e */
 
+  /* Number of times the device has been registered by ioctl */
+
+  uint8_t register_count;
+
+  /* Number of times interrupt occured */
+
+  uintptr_t int_count;
+
   /* Writable storage used by the upper half driver */
 
   struct gpio_signal_s gp_signals[CONFIG_DEV_GPIO_NSIGNALS];
@@ -162,6 +170,8 @@ struct gpio_dev_s
 
   FAR const struct gpio_operations_s *gp_ops;
 
+  FAR struct pollfd *fds[CONFIG_DEV_GPIO_NSIGNALS];
+
   /* Device specific, lower-half information may follow. */
 };