drm: make mode_valid callback optional

Many drm connectors do not need mode validation.
The patch makes this callback optional and removes dumb implementations.

v2: Rebase:
- imx move to a shared (but still dummy) ->mode_valid implementation.
- probe helpers have been extracted to drm_probe_helper.c

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com> (v1)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/drm/drm_crtc_helper.h b/include/drm/drm_crtc_helper.h
index 36a5febac2a6..7ffb59232e84 100644
--- a/include/drm/drm_crtc_helper.h
+++ b/include/drm/drm_crtc_helper.h
@@ -114,7 +114,7 @@ struct drm_encoder_helper_funcs {
 /**
  * drm_connector_helper_funcs - helper operations for connectors
  * @get_modes: get mode list for this connector
- * @mode_valid: is this mode valid on the given connector?
+ * @mode_valid (optional): is this mode valid on the given connector?
  *
  * The helper operations are called by the mid-layer CRTC helper.
  */