[PATCH v1 3/7] drm/bridge: Add drm_bridge_new_crtc_state() helper

[Sam Ravnborg]

drm_bridge_new_crtc_state() will be used by bridge drivers to provide
easy access to the mode from the drm_bridge_funcs operations.

The helper will be useful in the atomic operations of
struct drm_bridge_funcs.

Signed-off-by: Sam Ravnborg <sam at ravnborg.org>
Suggested-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Cc: Andrzej Hajda <a.hajda at samsung.com>
Cc: Neil Armstrong <narmstrong at baylibre.com>
Cc: Robert Foss <robert.foss at linaro.org>
Cc: Daniel Vetter <daniel at ffwll.ch>
---
 drivers/gpu/drm/drm_atomic.c | 34 ++++++++++++++++++++++++++++++++++
 include/drm/drm_atomic.h     |  3 +++
 2 files changed, 37 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index a8bbb021684b..93d513078e9a 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1133,6 +1133,40 @@ drm_atomic_get_new_bridge_state(struct drm_atomic_state *state,
 }
 EXPORT_SYMBOL(drm_atomic_get_new_bridge_state);
 
+/**
+ * drm_bridge_new_crtc_state - get crtc_state for the bridge
+ * @bridge: bridge object
+ * @old_bridge_state: state of the bridge
+ *
+ * This function returns the &struct drm_crtc_state for the given bridge/state,
+ * or NULL if no crtc_state could be looked up. In case no crtc_state then this is
+ * logged using WARN as the crtc_state is always expected to be present.
+ * This function is often used in the &struct drm_bridge_funcs operations.
+ */
+const struct drm_crtc_state *
+drm_bridge_new_crtc_state(struct drm_bridge *bridge,
+			  struct drm_bridge_state *old_bridge_state)
+{
+	struct drm_atomic_state *state = old_bridge_state->base.state;
+	const struct drm_connector_state *conn_state;
+	const struct drm_crtc_state *crtc_state;
+	struct drm_connector *connector;
+
+	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
+	if (WARN_ON(!connector))
+		return NULL;
+
+	conn_state = drm_atomic_get_new_connector_state(state, connector);
+	if (WARN_ON(!conn_state || !conn_state->crtc))
+		return NULL;
+
+	crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);
+	if (WARN_ON(!crtc_state))
+		return NULL;
+
+	return crtc_state;
+}
+
 /**
  * drm_atomic_add_encoder_bridges - add bridges attached to an encoder
  * @state: atomic state
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 1701c2128a5c..a3001eef98bf 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -1119,5 +1119,8 @@ drm_atomic_get_old_bridge_state(struct drm_atomic_state *state,
 struct drm_bridge_state *
 drm_atomic_get_new_bridge_state(struct drm_atomic_state *state,
 				struct drm_bridge *bridge);
+const struct drm_crtc_state *
+drm_bridge_new_crtc_state(struct drm_bridge *bridge,
+			  struct drm_bridge_state *old_bridge_state);
 
 #endif /* DRM_ATOMIC_H_ */
-- 
2.30.2