drm: Use new mode_valid() helpers in connector probe helper

This changes the connector probe helper function to use the new
encoder->mode_valid(), bridge->mode_valid() and crtc->mode_valid()
helper callbacks to validate the modes.

The new callbacks are optional so the behaviour remains the same
if they are not implemented. If they are, then the code loops
through all the connector's encodersXbridgesXcrtcs and calls the
callback.

If at least a valid encoderXbridgeXcrtc combination is found which
accepts the mode then the function returns MODE_OK.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Carlos Palminha <palminha@synopsys.com>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Changes v3->v4:
	- Change function name (Laurent)
Changes v2->v3:
	- Call also bridge->mode_valid (Daniel)
Changes v1->v2:
	- Use new helpers suggested by Ville
	- Change documentation (Daniel)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/d4e3ba87d822fa92f1b8773e441b9a02af3bde71.1495720737.git.joabreu@synopsys.com

drivers/gpu/drm/drm_probe_helper.c

@@ -83,6 +83,61 @@ drm_mode_validate_flag(const struct drm_display_mode *mode,
 	return MODE_OK;
 }
 
+static enum drm_mode_status
+drm_mode_validate_pipeline(struct drm_display_mode *mode,
+			    struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	uint32_t *ids = connector->encoder_ids;
+	enum drm_mode_status ret = MODE_OK;
+	unsigned int i;
+
+	/* Step 1: Validate against connector */
+	ret = drm_connector_mode_valid(connector, mode);
+	if (ret != MODE_OK)
+		return ret;
+
+	/* Step 2: Validate against encoders and crtcs */
+	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+		struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
+		struct drm_crtc *crtc;
+
+		if (!encoder)
+			continue;
+
+		ret = drm_encoder_mode_valid(encoder, mode);
+		if (ret != MODE_OK) {
+			/* No point in continuing for crtc check as this encoder
+			 * will not accept the mode anyway. If all encoders
+			 * reject the mode then, at exit, ret will not be
+			 * MODE_OK. */
+			continue;
+		}
+
+		ret = drm_bridge_mode_valid(encoder->bridge, mode);
+		if (ret != MODE_OK) {
+			/* There is also no point in continuing for crtc check
+			 * here. */
+			continue;
+		}
+
+		drm_for_each_crtc(crtc, dev) {
+			if (!drm_encoder_crtc_ok(encoder, crtc))
+				continue;
+
+			ret = drm_crtc_mode_valid(crtc, mode);
+			if (ret == MODE_OK) {
+				/* If we get to this point there is at least
+				 * one combination of encoder+crtc that works
+				 * for this mode. Lets return now. */
+				return ret;
+			}
+		}
+	}
+
+	return ret;
+}
+
 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 {
 	struct drm_cmdline_mode *cmdline_mode;
@@ -322,7 +377,11 @@ EXPORT_SYMBOL(drm_helper_probe_detect);
  *    - drm_mode_validate_flag() checks the modes against basic connector
  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
  *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform
- *      driver and/or hardware specific checks
+ *      driver and/or sink specific checks
+ *    - the optional &drm_crtc_helper_funcs.mode_valid,
+ *      &drm_bridge_funcs.mode_valid and &drm_encoder_helper_funcs.mode_valid
+ *      helpers can perform driver and/or source specific checks which are also
+ *      enforced by the modeset/atomic helpers
  *
  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
  *    accompanied by a debug message indicating the reason for the mode's
@@ -466,9 +525,9 @@ retry:
 		if (mode->status == MODE_OK)
 			mode->status = drm_mode_validate_flag(mode, mode_flags);
 
-		if (mode->status == MODE_OK && connector_funcs->mode_valid)
-			mode->status = connector_funcs->mode_valid(connector,
-								   mode);
+		if (mode->status == MODE_OK)
+			mode->status = drm_mode_validate_pipeline(mode,
+								  connector);
 	}
 
 prune: