fs/fs.h: Add register_driver_with_size function

It acts as register_driver but also populates the inode size.
This allows to return a non-zero size when calling stat() on an eeprom
driver.

The conditions (CONFIG_PSEUDOFS_FILE or CONFIG_FS_SHMFS) for the
declaration of the inode size field have also been removed so that other
drivers can populate this field in the future.

Signed-off-by: Antoine Juckler <6445757+ajuckler@users.noreply.github.com>

drivers/eeprom/i2c_xx24xx.c

@@ -924,5 +924,6 @@ int ee24xx_initialize(FAR struct i2c_master_s *bus, uint8_t devaddr,
     }
 #endif
 
-  return register_driver(devname, &g_ee24xx_fops, 0666, eedev);
+  return register_driver_with_size(devname, &g_ee24xx_fops, 0666, eedev,
+                                   eedev->size);
 }

drivers/eeprom/spi_xx25xx.c

@@ -860,5 +860,6 @@ int ee25xx_initialize(FAR struct spi_dev_s *dev, FAR char *devname,
         "%u per page, addrlen %u, readonly %d\n",
        devname, eedev->size, eedev->pgsize, eedev->addrlen, eedev->readonly);
 
-  return register_driver(devname, &g_ee25xx_fops, 0666, eedev);
+  return register_driver_with_size(devname, &g_ee25xx_fops, 0666, eedev,
+                                   eedev->size);
 }

fs/driver/fs_registerdriver.c

@@ -39,11 +39,75 @@
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: register_driver_with_size
+ *
+ * Description:
+ *   Register a character driver inode into the pseudo file system and
+ *   assign a size to it.
+ *
+ * Input Parameters:
+ *   path - The path to the inode to create
+ *   fops - The file operations structure
+ *   mode - inmode privileges
+ *   priv - Private, user data that will be associated with the inode.
+ *   size - Size in bytes to assign to the driver
+ *
+ * Returned Value:
+ *   Zero on success (with the inode point in 'inode'); A negated errno
+ *   value is returned on a failure (all error values returned by
+ *   inode_reserve):
+ *
+ *   EINVAL - 'path' is invalid for this operation
+ *   EEXIST - An inode already exists at 'path'
+ *   ENOMEM - Failed to allocate in-memory resources for the operation
+ *
+ ****************************************************************************/
+
+int register_driver_with_size(FAR const char *path,
+                              FAR const struct file_operations *fops,
+                              mode_t mode, FAR void *priv, size_t size)
+{
+  FAR struct inode *node;
+  int               ret;
+
+  sched_note_mark(NOTE_TAG_DRIVERS, path);
+
+  /* Insert a dummy node -- we need to hold the inode semaphore because we
+   * will have a momentarily bad structure.
+   */
+
+  inode_lock();
+  ret = inode_reserve(path, mode, &node);
+  if (ret >= 0)
+    {
+      /* We have it, now populate it with driver specific information.
+       * NOTE that the initial reference count on the new inode is zero.
+       */
+
+      INODE_SET_DRIVER(node);
+
+      node->u.i_ops   = fops;
+      node->i_private = priv;
+      node->i_size    = size;
+
+      inode_unlock();
+#ifdef CONFIG_FS_NOTIFY
+      notify_create(path);
+#endif
+
+      return OK;
+    }
+
+  inode_unlock();
+  return ret;
+}
+
 /****************************************************************************
  * Name: register_driver
  *
  * Description:
- *   Register a character driver inode the pseudo file system.
+ *   Register a character driver inode into the pseudo file system.
  *
  * Input Parameters:
  *   path - The path to the inode to create
@@ -66,34 +130,5 @@ int register_driver(FAR const char *path,
                     FAR const struct file_operations *fops,
                     mode_t mode, FAR void *priv)
 {
-  FAR struct inode *node;
-  int ret;
-
-  sched_note_mark(NOTE_TAG_DRIVERS, path);
-
-  /* Insert a dummy node -- we need to hold the inode semaphore because we
-   * will have a momentarily bad structure.
-   */
-
-  inode_lock();
-  ret = inode_reserve(path, mode, &node);
-  if (ret >= 0)
-    {
-      /* We have it, now populate it with driver specific information.
-       * NOTE that the initial reference count on the new inode is zero.
-       */
-
-      INODE_SET_DRIVER(node);
-
-      node->u.i_ops   = fops;
-      node->i_private = priv;
-      inode_unlock();
-#ifdef CONFIG_FS_NOTIFY
-      notify_create(path);
-#endif
-      return OK;
-    }
-
-  inode_unlock();
-  return ret;
+  return register_driver_with_size(path, fops, mode, priv, 0);
 }

fs/vfs/fs_stat.c

@@ -428,9 +428,9 @@ int inode_stat(FAR struct inode *inode, FAR struct stat *buf, int resolve)
         {
           /* What is it if it also has child inodes? */
 
-#ifdef CONFIG_PSEUDOFS_FILE
           buf->st_size = inode->i_size;
 
+#ifdef CONFIG_PSEUDOFS_FILE
           if (inode_is_pseudofile(inode))
             {
               buf->st_mode |= S_IFREG;

include/nuttx/fs/fs.h

@@ -407,9 +407,7 @@ struct inode
   uint16_t          i_flags;    /* Flags for inode */
   union inode_ops_u u;          /* Inode operations */
   ino_t             i_ino;      /* Inode serial number */
-#if defined(CONFIG_PSEUDOFS_FILE) || defined(CONFIG_FS_SHMFS)
   size_t            i_size;     /* The size of per inode driver */
-#endif
 #ifdef CONFIG_PSEUDOFS_ATTRIBUTES
   mode_t            i_mode;     /* Access mode flags */
   uid_t             i_owner;    /* Owner */
@@ -625,6 +623,35 @@ int register_driver(FAR const char *path,
                     FAR const struct file_operations *fops, mode_t mode,
                     FAR void *priv);
 
+/****************************************************************************
+ * Name: register_driver_with_size
+ *
+ * Description:
+ *   Register a character driver inode into the pseudo file system and
+ *   assign a size to it.
+ *
+ * Input Parameters:
+ *   path - The path to the inode to create
+ *   fops - The file operations structure
+ *   mode - inmode privileges
+ *   priv - Private, user data that will be associated with the inode.
+ *   size - Size in bytes to assign to the driver
+ *
+ * Returned Value:
+ *   Zero on success (with the inode point in 'inode'); A negated errno
+ *   value is returned on a failure (all error values returned by
+ *   inode_reserve):
+ *
+ *   EINVAL - 'path' is invalid for this operation
+ *   EEXIST - An inode already exists at 'path'
+ *   ENOMEM - Failed to allocate in-memory resources for the operation
+ *
+ ****************************************************************************/
+
+int register_driver_with_size(FAR const char *path,
+                              FAR const struct file_operations *fops,
+                              mode_t mode, FAR void *priv, size_t size);
+
 /****************************************************************************
  * Name: register_blockdriver
  *