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@xxxxxx>
---
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..d9452e98 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 %s to %s\n",
+ dev_name(connector->dev->dev), dev_name(panel->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;
--
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