[PATCH 09/16] video: vpl: handle missing struct vpl::ioctl gracefully

[Ahmad Fatoum <a.fatoum@barebox.org>]

Display controllers don't usually implement the ioctl callback, because
they are invoked via the register_framebuffer API and only need to call
other drivers' ioctl and their own is never called.

Yet, when by mistake an ioctl is directed at a display controller, we
currently crash. Let's handle this case gracefully instead.

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 drivers/video/vpl.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/video/vpl.c b/drivers/video/vpl.c
index 0b86ef9f7e81..da8bd93b7d6a 100644
--- a/drivers/video/vpl.c
+++ b/drivers/video/vpl.c
@@ -106,6 +106,7 @@ static int vpl_foreach_endpoint(struct vpl *vpl, unsigned int port,
 }
 
 struct vpl_ioctl {
+	int err;
 	unsigned cmd;
 	void *ptr;
 };
@@ -114,6 +115,11 @@ static int vpl_remote_ioctl(struct vpl *vpl, unsigned port, void *_data)
 {
 	struct vpl_ioctl *data = _data;
 
+	if (!vpl->ioctl) {
+		data->err = -EOPNOTSUPP;
+		return 0;
+	}
+
 	return vpl->ioctl(vpl, port, data->cmd, data->ptr);
 }
 
@@ -122,5 +128,5 @@ int vpl_ioctl(struct vpl *vpl, unsigned int port,
 {
 	struct vpl_ioctl data = { .cmd = cmd, .ptr = ptr };
 
-	return vpl_foreach_endpoint(vpl, port, vpl_remote_ioctl, &data);
+	return vpl_foreach_endpoint(vpl, port, vpl_remote_ioctl, &data) ?: data.err;
 }
-- 
2.39.5