drm/omap: dss: convert to of_drm_find_and_get_bridge()

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done.

omapdss_device_init_output() can take one bridge pointer in out->bridge or
two pointers in out->bridge and out->next_bridge. Ensure each has a
corresponding drm_bridge_get() and add drm_bridge_put() calls in the
cleanup code.

Also slightly change the initial code assigning out->panel and out->bridge
to ensure and clarify that either out->panel or out->bridge is set in the
function prologue, not both. If both were set, the 'if (out->panel){...}'
code that follows would overwrite out->bridge without having put the
reference.

Finally, take a reference in case a panel_bridge is added using
drm_panel_bridge_add(). This ensures we always need to put a reference,
which came either from of_drm_find_and_get_bridge() or by the
drm_panel_bridge_add+drm_bridge_get() branch.

Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260402-drm-bridge-alloc-getput-drm_of_find_bridge-4-v4-4-421781c8c061@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

diff --git a/drivers/gpu/drm/omapdrm/dss/output.c b/drivers/gpu/drm/omapdrm/dss/output.c
index 7378e855c278c3809bc431ff48a1c5a41b7dedfc..ca891aba382092c36051e764cbb68b1dade5288a 100644 (file)
--- a/drivers/gpu/drm/omapdrm/dss/output.c
+++ b/drivers/gpu/drm/omapdrm/dss/output.c
@@ -30,11 +30,13 @@ int omapdss_device_init_output(struct omap_dss_device *out,
                return 0;
        }
 
-       out->bridge = of_drm_find_bridge(remote_node);
        out->panel = of_drm_find_panel(remote_node);
        if (IS_ERR(out->panel))
                out->panel = NULL;
 
+       if (!out->panel)
+               out->bridge = of_drm_find_and_get_bridge(remote_node);
+
        of_node_put(remote_node);
 
        if (out->panel) {
@@ -49,7 +51,7 @@ int omapdss_device_init_output(struct omap_dss_device *out,
                        goto error;
                }
 
-               out->bridge = bridge;
+               out->bridge = drm_bridge_get(bridge);
        }
 
        if (local_bridge) {
@@ -59,7 +61,7 @@ int omapdss_device_init_output(struct omap_dss_device *out,
                }
 
                out->next_bridge = out->bridge;
-               out->bridge = local_bridge;
+               out->bridge = drm_bridge_get(local_bridge);
        }
 
        if (!out->bridge) {
@@ -79,6 +81,9 @@ void omapdss_device_cleanup_output(struct omap_dss_device *out)
        if (out->bridge && out->panel)
                drm_panel_bridge_remove(out->next_bridge ?
                                        out->next_bridge : out->bridge);
+
+       drm_bridge_put(out->next_bridge);
+       drm_bridge_put(out->bridge);
 }
 
 void dss_mgr_set_timings(struct omap_dss_device *dssdev,