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

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

drivers/gpu/drm/drm_panel.c

+10 −0
Original line number Diff line number Diff line
@@ -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>
@@ -104,6 +105,13 @@ int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector) 
	if (panel->connector)

		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->drm = connector->dev;
@@ -125,6 +133,8 @@ EXPORT_SYMBOL(drm_panel_attach); 
 */

int drm_panel_detach(struct drm_panel *panel)

{

	device_link_del(panel->link);



	panel->connector = NULL;

	panel->drm = NULL;

include/drm/drm_panel.h

+1 −0
Original line number Diff line number Diff line
@@ -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;