drm: Add atomic variants for bridge enable/disable

This patch adds atomic variants for all of
pre_enable/enable/disable/post_disable bridge functions. These will be
called from the appropriate atomic helper functions. If the bridge
driver doesn't implement the atomic version of the function, we will
fall back to the vanilla implementation.

Note that some drivers call drm_bridge_disable directly, and these cases
are not covered. It's up to the driver to decide whether to implement
both atomic_disable and disable, or if it's not necessary.

Changes in v3:
- Added to the patchset
Changes in v4:
- Fix up docbook references (Daniel)
Changes in v5:
- None

Link to v3: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Link to v4: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

Cc: Daniel Vetter <[e-mail]>
Cc: Ville Syrjälä <[e-mail]>
Tested-by: Heiko Stuebner <[e-mail]>
Reviewed-by: Daniel Vetter <[e-mail]>
Reviewed-by: Andrzej Hajda <[e-mail]>
Signed-off-by: Sean Paul <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/drm_atomic_helper.c

···
 		 * Each encoder has at most one connector (since we always steal
 		 * it away), so we won't call disable hooks twice.
 		 */
-		drm_bridge_disable(encoder->bridge);
+		drm_atomic_bridge_disable(encoder->bridge, old_state);
 
 		/* Right function depends upon target state. */
 		if (funcs) {
···
 				funcs->dpms(encoder, DRM_MODE_DPMS_OFF);
 		}
 
-		drm_bridge_post_disable(encoder->bridge);
+		drm_atomic_bridge_post_disable(encoder->bridge, old_state);
 	}
 
 	for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
···
 		 * Each encoder has at most one connector (since we always steal
 		 * it away), so we won't call enable hooks twice.
 		 */
-		drm_bridge_pre_enable(encoder->bridge);
+		drm_atomic_bridge_pre_enable(encoder->bridge, old_state);
 
 		if (funcs) {
 			if (funcs->atomic_enable)
···
 				funcs->commit(encoder);
 		}
 
-		drm_bridge_enable(encoder->bridge);
+		drm_atomic_bridge_enable(encoder->bridge, old_state);
 	}
 
 	drm_atomic_helper_commit_writebacks(dev, old_state);

drivers/gpu/drm/drm_bridge.c

···
 }
 EXPORT_SYMBOL(drm_bridge_enable);
 
+/**
+ * drm_atomic_bridge_disable - disables all bridges in the encoder chain
+ * @bridge: bridge control structure
+ * @state: atomic state being committed
+ *
+ * Calls &drm_bridge_funcs.atomic_disable (falls back on
+ * &drm_bridge_funcs.disable) op for all the bridges in the encoder chain,
+ * starting from the last bridge to the first. These are called before calling
+ * &drm_encoder_helper_funcs.atomic_disable
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ */
+void drm_atomic_bridge_disable(struct drm_bridge *bridge,
+			       struct drm_atomic_state *state)
+{
+	if (!bridge)
+		return;
+
+	drm_atomic_bridge_disable(bridge->next, state);
+
+	if (bridge->funcs->atomic_disable)
+		bridge->funcs->atomic_disable(bridge, state);
+	else if (bridge->funcs->disable)
+		bridge->funcs->disable(bridge);
+}
+EXPORT_SYMBOL(drm_atomic_bridge_disable);
+
+/**
+ * drm_atomic_bridge_post_disable - cleans up after disabling all bridges in the
+ *				    encoder chain
+ * @bridge: bridge control structure
+ * @state: atomic state being committed
+ *
+ * Calls &drm_bridge_funcs.atomic_post_disable (falls back on
+ * &drm_bridge_funcs.post_disable) op for all the bridges in the encoder chain,
+ * starting from the first bridge to the last. These are called after completing
+ * &drm_encoder_helper_funcs.atomic_disable
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ */
+void drm_atomic_bridge_post_disable(struct drm_bridge *bridge,
+				    struct drm_atomic_state *state)
+{
+	if (!bridge)
+		return;
+
+	if (bridge->funcs->atomic_post_disable)
+		bridge->funcs->atomic_post_disable(bridge, state);
+	else if (bridge->funcs->post_disable)
+		bridge->funcs->post_disable(bridge);
+
+	drm_atomic_bridge_post_disable(bridge->next, state);
+}
+EXPORT_SYMBOL(drm_atomic_bridge_post_disable);
+
+/**
+ * drm_atomic_bridge_pre_enable - prepares for enabling all bridges in the
+ *				  encoder chain
+ * @bridge: bridge control structure
+ * @state: atomic state being committed
+ *
+ * Calls &drm_bridge_funcs.atomic_pre_enable (falls back on
+ * &drm_bridge_funcs.pre_enable) op for all the bridges in the encoder chain,
+ * starting from the last bridge to the first. These are called before calling
+ * &drm_encoder_helper_funcs.atomic_enable
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ */
+void drm_atomic_bridge_pre_enable(struct drm_bridge *bridge,
+				  struct drm_atomic_state *state)
+{
+	if (!bridge)
+		return;
+
+	drm_atomic_bridge_pre_enable(bridge->next, state);
+
+	if (bridge->funcs->atomic_pre_enable)
+		bridge->funcs->atomic_pre_enable(bridge, state);
+	else if (bridge->funcs->pre_enable)
+		bridge->funcs->pre_enable(bridge);
+}
+EXPORT_SYMBOL(drm_atomic_bridge_pre_enable);
+
+/**
+ * drm_atomic_bridge_enable - enables all bridges in the encoder chain
+ * @bridge: bridge control structure
+ * @state: atomic state being committed
+ *
+ * Calls &drm_bridge_funcs.atomic_enable (falls back on
+ * &drm_bridge_funcs.enable) op for all the bridges in the encoder chain,
+ * starting from the first bridge to the last. These are called after completing
+ * &drm_encoder_helper_funcs.atomic_enable
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ */
+void drm_atomic_bridge_enable(struct drm_bridge *bridge,
+			      struct drm_atomic_state *state)
+{
+	if (!bridge)
+		return;
+
+	if (bridge->funcs->atomic_enable)
+		bridge->funcs->atomic_enable(bridge, state);
+	else if (bridge->funcs->enable)
+		bridge->funcs->enable(bridge);
+
+	drm_atomic_bridge_enable(bridge->next, state);
+}
+EXPORT_SYMBOL(drm_atomic_bridge_enable);
+
 #ifdef CONFIG_OF
 /**
  * of_drm_find_bridge - find the bridge corresponding to the device node in

include/drm/drm_bridge.h

···
 	 * The enable callback is optional.
 	 */
 	void (*enable)(struct drm_bridge *bridge);
+
+	/**
+	 * @atomic_pre_enable:
+	 *
+	 * This callback should enable the bridge. It is called right before
+	 * the preceding element in the display pipe is enabled. If the
+	 * preceding element is a bridge this means it's called before that
+	 * bridge's @atomic_pre_enable or @pre_enable function. If the preceding
+	 * element is a &drm_encoder it's called right before the encoder's
+	 * &drm_encoder_helper_funcs.atomic_enable hook.
+	 *
+	 * The display pipe (i.e. clocks and timing signals) feeding this bridge
+	 * will not yet be running when this callback is called. The bridge must
+	 * not enable the display link feeding the next bridge in the chain (if
+	 * there is one) when this callback is called.
+	 *
+	 * Note that this function will only be invoked in the context of an
+	 * atomic commit. It will not be invoked from &drm_bridge_pre_enable. It
+	 * would be prudent to also provide an implementation of @pre_enable if
+	 * you are expecting driver calls into &drm_bridge_pre_enable.
+	 *
+	 * The @atomic_pre_enable callback is optional.
+	 */
+	void (*atomic_pre_enable)(struct drm_bridge *bridge,
+				  struct drm_atomic_state *state);
+
+	/**
+	 * @atomic_enable:
+	 *
+	 * This callback should enable the bridge. It is called right after
+	 * the preceding element in the display pipe is enabled. If the
+	 * preceding element is a bridge this means it's called after that
+	 * bridge's @atomic_enable or @enable function. If the preceding element
+	 * is a &drm_encoder it's called right after the encoder's
+	 * &drm_encoder_helper_funcs.atomic_enable hook.
+	 *
+	 * The bridge can assume that the display pipe (i.e. clocks and timing
+	 * signals) feeding it is running when this callback is called. This
+	 * callback must enable the display link feeding the next bridge in the
+	 * chain if there is one.
+	 *
+	 * Note that this function will only be invoked in the context of an
+	 * atomic commit. It will not be invoked from &drm_bridge_enable. It
+	 * would be prudent to also provide an implementation of @enable if
+	 * you are expecting driver calls into &drm_bridge_enable.
+	 *
+	 * The enable callback is optional.
+	 */
+	void (*atomic_enable)(struct drm_bridge *bridge,
+			      struct drm_atomic_state *state);
+	/**
+	 * @atomic_disable:
+	 *
+	 * This callback should disable the bridge. It is called right before
+	 * the preceding element in the display pipe is disabled. If the
+	 * preceding element is a bridge this means it's called before that
+	 * bridge's @atomic_disable or @disable vfunc. If the preceding element
+	 * is a &drm_encoder it's called right before the
+	 * &drm_encoder_helper_funcs.atomic_disable hook.
+	 *
+	 * The bridge can assume that the display pipe (i.e. clocks and timing
+	 * signals) feeding it is still running when this callback is called.
+	 *
+	 * Note that this function will only be invoked in the context of an
+	 * atomic commit. It will not be invoked from &drm_bridge_disable. It
+	 * would be prudent to also provide an implementation of @disable if
+	 * you are expecting driver calls into &drm_bridge_disable.
+	 *
+	 * The disable callback is optional.
+	 */
+	void (*atomic_disable)(struct drm_bridge *bridge,
+			       struct drm_atomic_state *state);
+
+	/**
+	 * @atomic_post_disable:
+	 *
+	 * This callback should disable the bridge. It is called right after the
+	 * preceding element in the display pipe is disabled. If the preceding
+	 * element is a bridge this means it's called after that bridge's
+	 * @atomic_post_disable or @post_disable function. If the preceding
+	 * element is a &drm_encoder it's called right after the encoder's
+	 * &drm_encoder_helper_funcs.atomic_disable hook.
+	 *
+	 * The bridge must assume that the display pipe (i.e. clocks and timing
+	 * signals) feeding it is no longer running when this callback is
+	 * called.
+	 *
+	 * Note that this function will only be invoked in the context of an
+	 * atomic commit. It will not be invoked from &drm_bridge_post_disable.
+	 * It would be prudent to also provide an implementation of
+	 * @post_disable if you are expecting driver calls into
+	 * &drm_bridge_post_disable.
+	 *
+	 * The post_disable callback is optional.
+	 */
+	void (*atomic_post_disable)(struct drm_bridge *bridge,
+				    struct drm_atomic_state *state);
 };
 
 /**
···
 			 const struct drm_display_mode *adjusted_mode);
 void drm_bridge_pre_enable(struct drm_bridge *bridge);
 void drm_bridge_enable(struct drm_bridge *bridge);
+
+void drm_atomic_bridge_disable(struct drm_bridge *bridge,
+			       struct drm_atomic_state *state);
+void drm_atomic_bridge_post_disable(struct drm_bridge *bridge,
+				    struct drm_atomic_state *state);
+void drm_atomic_bridge_pre_enable(struct drm_bridge *bridge,
+				  struct drm_atomic_state *state);
+void drm_atomic_bridge_enable(struct drm_bridge *bridge,
+			      struct drm_atomic_state *state);
 
 #ifdef CONFIG_DRM_PANEL_BRIDGE
 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,