drm: simple_kms_helper: Add mode_valid() callback support

The PL111 needs to filter valid modes based on memory bandwidth.
I guess it is a pretty simple operation, so we can still claim
the DRM KMS helper pipeline is simple after adding this (optional)
vtable callback.

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180220072859.3386-1-linus.walleij@linaro.org

1 files changed, 14 insertions, 0 deletions

diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
index 6d9adbb46293..d9e4c3c3f009 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -22,6 +22,20 @@ struct drm_simple_display_pipe;
  */
 struct drm_simple_display_pipe_funcs {
         /**
+         * @mode_valid:
+         *
+         * This function is called to filter out valid modes from the
+         * suggestions suggested by the bridge or display. This optional
+         * hook is passed in when initializing the pipeline.
+         *
+         * RETURNS:
+         *
+         * drm_mode_status Enum
+         */
+        enum drm_mode_status (*mode_valid)(struct drm_crtc *crtc,
+                                           const struct drm_display_mode *mode);
+
+        /**
          * @enable:
          *
          * This function should be used to enable the pipeline.