video: pxa3xx-gcu: provide an empty .open call

This is necessary in order to make the core set file->private_data to
miscdev in use. We need that information later to dereference the
container of the device, so we can get access to our private struct from
other callbacks.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/pxa3xx-gcu.c

@@ -373,6 +373,15 @@ static inline struct pxa3xx_gcu_priv *to_pxa3xx_gcu_priv(struct file *file)
 	return container_of(dev, struct pxa3xx_gcu_priv, misc_dev);
 }
 
+/*
+ * provide an empty .open callback, so the core sets file->private_data
+ * for us.
+ */
+static int pxa3xx_gcu_open(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
 static ssize_t
 pxa3xx_gcu_write(struct file *file, const char *buff,
 		 size_t count, loff_t *offp)
@@ -571,6 +580,7 @@ pxa3xx_gcu_free_buffers(struct device *dev,
 
 static const struct file_operations pxa3xx_gcu_miscdev_fops = {
 	.owner =		THIS_MODULE,
+	.open =			pxa3xx_gcu_open,
 	.write =		pxa3xx_gcu_write,
 	.unlocked_ioctl =	pxa3xx_gcu_ioctl,
 	.mmap =			pxa3xx_gcu_mmap,