[PATCH v4 02/15] drm/bridge: Provide a helper to retrieve current bridge state

[Maxime Ripard <mripard@kernel.org>]

The current bridge state is accessible from the drm_bridge structure,
but since it's fairly indirect it's not easy to figure out.

Provide a helper to retrieve it.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 include/drm/drm_bridge.h | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 2b65466540306feb0694abdc7cd801369cb9c9f0..6fb1da7c195e99143a67a999d16fe361c1e3f4ab 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -955,10 +955,42 @@ static inline struct drm_bridge *of_drm_find_bridge(struct device_node *np)
 {
 	return NULL;
 }
 #endif
 
+/**
+ * drm_bridge_get_current_state() - Get the current bridge state
+ * @bridge: bridge object
+ *
+ * This function must be called with the modeset lock held.
+ *
+ * RETURNS:
+ *
+ * The current bridge state, or NULL if there is none.
+ */
+static inline struct drm_bridge_state *
+drm_bridge_get_current_state(struct drm_bridge *bridge)
+{
+	if (!bridge)
+		return NULL;
+
+	/*
+	 * Only atomic bridges will have bridge->base initialized by
+	 * drm_atomic_private_obj_init(), so we need to make sure we're
+	 * working with one before we try to use the lock.
+	 */
+	if (!bridge->funcs || !bridge->funcs->atomic_reset)
+		return NULL;
+
+	drm_modeset_lock_assert_held(&bridge->base.lock);
+
+	if (!bridge->base.state)
+		return NULL;
+
+	return drm_priv_to_bridge_state(bridge->base.state);
+}
+
 /**
  * drm_bridge_get_next_bridge() - Get the next bridge in the chain
  * @bridge: bridge object
  *
  * RETURNS:

-- 
2.48.1