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

@@ -40,16 +40,18 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: register_driver
+ * Name: register_driver_with_size
  *
  * Description:
- *   Register a character driver inode the pseudo file system.
+ *   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
@@ -62,9 +64,9 @@
  *
  ****************************************************************************/
 
-int register_driver(FAR const char *path,
+int register_driver_with_size(FAR const char *path,
                               FAR const struct file_operations *fops,
-                    mode_t mode, FAR void *priv)
+                              mode_t mode, FAR void *priv, size_t size)
 {
   FAR struct inode *node;
   int               ret;
@@ -87,13 +89,46 @@ int register_driver(FAR const char *path,
 
       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 into the pseudo file system.
+ *
+ * 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.
+ *
+ * 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(FAR const char *path,
+                    FAR const struct file_operations *fops,
+                    mode_t mode, FAR void *priv)
+{
+  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
  *