drivers/gpio: save memory if dont support signal

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

drivers/ioexpander/Kconfig

@@ -499,6 +499,14 @@ config DEV_GPIO
 		Enables a simple GPIO input/output driver to support application-
 		space testing of hardware.
 
+config DEV_GPIO_NPOLLWAITERS
+	int "Max number of polls"
+	default 1
+	depends on DEV_GPIO
+	---help---
+		The maximum number of polls that can be registered with the GPIO
+		driver
+
 config DEV_GPIO_NSIGNALS
 	int "Max number of signals"
 	default 1

drivers/ioexpander/gpio.c

@@ -87,14 +87,19 @@ static const struct file_operations g_gpio_drvrops =
 
 static int gpio_handler(FAR struct gpio_dev_s *dev, uint8_t pin)
 {
+#if CONFIG_DEV_GPIO_NSIGNALS > 0
   int i;
+#endif
 
   DEBUGASSERT(dev != NULL);
 
   dev->int_count++;
 
-  poll_notify(dev->fds, CONFIG_DEV_GPIO_NSIGNALS, POLLIN);
+#if CONFIG_DEV_GPIO_NPOLLWAITERS > 0
+  poll_notify(dev->fds, CONFIG_DEV_GPIO_NPOLLWAITERS, POLLIN);
+#endif
 
+#if CONFIG_DEV_GPIO_NSIGNALS > 0
   for (i = 0; i < CONFIG_DEV_GPIO_NSIGNALS; i++)
     {
       FAR struct gpio_signal_s *signal = &dev->gp_signals[i];
@@ -107,6 +112,7 @@ static int gpio_handler(FAR struct gpio_dev_s *dev, uint8_t pin)
       nxsig_notification(signal->gp_pid, &signal->gp_event,
                          SI_QUEUE, &signal->gp_work);
     }
+#endif
 
   return OK;
 }
@@ -305,10 +311,12 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
   FAR struct inode *inode;
   FAR struct gpio_dev_s *dev;
   irqstate_t flags;
-  pid_t pid;
   int ret = OK;
+#if CONFIG_DEV_GPIO_NSIGNALS > 0
+  pid_t pid;
   int i;
   int j;
+#endif
 
   inode = filep->f_inode;
   DEBUGASSERT(inode->i_private != NULL);
@@ -383,6 +391,7 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
         if (dev->gp_pintype >= GPIO_INTERRUPT_PIN)
           {
             flags = enter_critical_section();
+#if CONFIG_DEV_GPIO_NSIGNALS > 0
             if (arg)
               {
                 pid = nxsched_getpid();
@@ -406,6 +415,7 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
                     break;
                   }
               }
+#endif
 
             if (dev->register_count++ > 0)
               {
@@ -442,8 +452,9 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
       case GPIOC_UNREGISTER:
         if (dev->gp_pintype >= GPIO_INTERRUPT_PIN)
           {
-            pid = nxsched_getpid();
             flags = enter_critical_section();
+#if CONFIG_DEV_GPIO_NSIGNALS > 0
+            pid = nxsched_getpid();
             for (i = 0; i < CONFIG_DEV_GPIO_NSIGNALS; i++)
               {
                 if (pid == dev->gp_signals[i].gp_pid)
@@ -467,6 +478,7 @@ static int gpio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
                     break;
                   }
               }
+#endif
 
             if (--dev->register_count > 0)
               {
@@ -583,22 +595,26 @@ 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)
 {
+#if CONFIG_DEV_GPIO_NPOLLWAITERS > 0
   FAR struct inode *inode = filep->f_inode;
   FAR struct gpio_dev_s *dev = inode->i_private;
+  int i;
+#endif
+
   irqstate_t flags;
   int ret = OK;
-  int i;
 
   /* Are we setting up the poll?  Or tearing it down? */
 
   flags = enter_critical_section();
   if (setup)
     {
+#if CONFIG_DEV_GPIO_NPOLLWAITERS > 0
       /* 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++)
+      for (i = 0; i < CONFIG_DEV_GPIO_NPOLLWAITERS; i++)
         {
           /* Find an available slot */
 
@@ -620,7 +636,8 @@ static int gpio_poll(FAR struct file *filep,
             }
         }
 
-      if (i >= CONFIG_DEV_GPIO_NSIGNALS)
+      if (i >= CONFIG_DEV_GPIO_NPOLLWAITERS)
+#endif
         {
           fds->priv = NULL;
           ret       = -EBUSY;

include/nuttx/ioexpander/gpio.h

@@ -162,7 +162,9 @@ struct gpio_dev_s
 
   /* Writable storage used by the upper half driver */
 
+#if CONFIG_DEV_GPIO_NSIGNALS > 0
   struct gpio_signal_s gp_signals[CONFIG_DEV_GPIO_NSIGNALS];
+#endif
 
   /* Read-only pointer to GPIO device operations (also provided by the
    * lower half driver).
@@ -170,7 +172,9 @@ struct gpio_dev_s
 
   FAR const struct gpio_operations_s *gp_ops;
 
-  FAR struct pollfd *fds[CONFIG_DEV_GPIO_NSIGNALS];
+#if CONFIG_DEV_GPIO_NPOLLWAITERS > 0
+  FAR struct pollfd *fds[CONFIG_DEV_GPIO_NPOLLWAITERS];
+#endif
 
   /* Device specific, lower-half information may follow. */
 };