Commit 0c08754b authored by Jyri Sarha's avatar Jyri Sarha Committed by Thierry Reding

drm/panel: Add device_link from panel device to DRM device

Add device_link from panel device (supplier) to DRM device (consumer)
when drm_panel_attach() is called. This patch should protect the master
DRM driver if an attached panel driver unbinds while it is in use. The
device_link 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 consumer DRM driver, not the
panel driver, otherwise both drivers are racing to delete the same link.
Signed-off-by: default avatarJyri Sarha <jsarha@ti.com>
Reviewed-by: default avatarEric Anholt <eric@anholt.net>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b53584fd988d045c13de22d81825395b0ae0aad7.1524727888.git.jsarha@ti.com
parent 38992c57
...@@ -24,6 +24,7 @@ ...@@ -24,6 +24,7 @@
#include <linux/err.h> #include <linux/err.h>
#include <linux/module.h> #include <linux/module.h>
#include <drm/drm_device.h>
#include <drm/drm_crtc.h> #include <drm/drm_crtc.h>
#include <drm/drm_panel.h> #include <drm/drm_panel.h>
...@@ -104,6 +105,13 @@ int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector) ...@@ -104,6 +105,13 @@ int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
if (panel->connector) if (panel->connector)
return -EBUSY; return -EBUSY;
panel->link = device_link_add(connector->dev->dev, panel->dev, 0);
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->connector = connector;
panel->drm = connector->dev; panel->drm = connector->dev;
...@@ -125,6 +133,8 @@ EXPORT_SYMBOL(drm_panel_attach); ...@@ -125,6 +133,8 @@ EXPORT_SYMBOL(drm_panel_attach);
*/ */
int drm_panel_detach(struct drm_panel *panel) int drm_panel_detach(struct drm_panel *panel)
{ {
device_link_del(panel->link);
panel->connector = NULL; panel->connector = NULL;
panel->drm = NULL; panel->drm = NULL;
......
...@@ -89,6 +89,7 @@ struct drm_panel { ...@@ -89,6 +89,7 @@ struct drm_panel {
struct drm_device *drm; struct drm_device *drm;
struct drm_connector *connector; struct drm_connector *connector;
struct device *dev; struct device *dev;
struct device_link *link;
const struct drm_panel_funcs *funcs; const struct drm_panel_funcs *funcs;
......
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