Add device_link from panel device (supplier) to drm device (consumer) with DL_FLAG_AUTOREMOVE when drm_panel_attach() is called. Currently the master drm driver is not protected against the attached. The device_link with DL_FLAG_AUTOREMOVE should make sure the drm device is unbound before the panel driver becomes unavailable.
The device_link is removed when drm_panel_detach() is called. The drm_panel_detach() should be called by the panel driver it self when it is removed. Otherwise the both driver are racing to delete the same link.
Signed-off-by: Jyri Sarha jsarha@ti.com --- drivers/gpu/drm/drm_panel.c | 12 ++++++++++++ include/drm/drm_panel.h | 1 + 2 files changed, 13 insertions(+)
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index 308d442..afa8337 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -24,6 +24,7 @@ #include <linux/err.h> #include <linux/module.h>
+#include <drm/drm_device.h> #include <drm/drm_crtc.h> #include <drm/drm_panel.h>
@@ -98,9 +99,18 @@ EXPORT_SYMBOL(drm_panel_remove); */ int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector) { + u32 flags = DL_FLAG_AUTOREMOVE; + if (panel->connector) return -EBUSY;
+ panel->link = device_link_add(connector->dev->dev, panel->dev, flags); + if (!panel->link) { + dev_err(panel->dev, "failed to link panel to %s\n", + dev_name(connector->dev->dev)); + return -EINVAL; + } + panel->connector = connector; panel->drm = connector->dev;
@@ -119,6 +129,8 @@ EXPORT_SYMBOL(drm_panel_attach); */ int drm_panel_detach(struct drm_panel *panel) { + device_link_del(panel->link); + panel->connector = NULL; panel->drm = NULL;
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 14ac240..26a1b5f 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -89,6 +89,7 @@ struct drm_panel { struct drm_device *drm; struct drm_connector *connector; struct device *dev; + struct device_link *link;
const struct drm_panel_funcs *funcs;