drm: of: always initialize panel in drm_of_find_panel_or_bridge()

The callers expect "panel" to be initialized, but that isn't true if we
return -ENODEV.  It causes bugs like:

    drivers/gpu/drm/tve200/tve200_drv.c:83 tve200_modeset_init()
    error: uninitialized symbol 'panel'.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20170925103038.lvr5msjvekwczctn@mwanda

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index 8dafbdfcd2ea087865b233acd6b3622fb8b9e081..4c191c050e7dac2093abdbfbbd4e18d1efb182b2 100644 (file)
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -233,6 +233,8 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
 
        if (!panel && !bridge)
                return -EINVAL;
+       if (panel)
+               *panel = NULL;
 
        remote = of_graph_get_remote_node(np, port, endpoint);
        if (!remote)