Commit e1a29c6c authored by Andrzej Pietrasiewicz's avatar Andrzej Pietrasiewicz Committed by Neil Armstrong
Browse files

drm: Add ddc link in sysfs created by drm_connector 



Add generic code which creates symbolic links in sysfs, pointing to ddc
interface used by a particular video output. For example:

ls -l /sys/class/drm/card0-HDMI-A-1/ddc
lrwxrwxrwx 1 root root 0 Jun 24 10:42 /sys/class/drm/card0-HDMI-A-1/ddc \
	-> ../../../../soc/13880000.i2c/i2c-2

This makes it easy for user to associate a display with its ddc adapter
and use e.g. ddcutil to control the chosen monitor.

This patch adds an i2c_adapter pointer to struct drm_connector. Particular
drivers can then use it instead of using their own private instance. If a
connector contains a ddc, then create a symbolic link in sysfs.

Signed-off-by: default avatarAndrzej Pietrasiewicz <andrzej.p@collabora.com>
Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
Reviewed-by: default avatarEmil Velikov <emil.velikov@collabora.com>
Reviewed-by: default avatarSam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarNeil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/d470def6cd661b777faeee67b5838a4623c4010e.1564161140.git.andrzej.p@collabora.com
parent 77b8cabf

drivers/gpu/drm/drm_sysfs.c

+8 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/err.h>

#include <linux/export.h>

#include <linux/gfp.h>

#include <linux/i2c.h>

#include <linux/kdev_t.h>

#include <linux/slab.h>
@@ -294,6 +295,9 @@ int drm_sysfs_connector_add(struct drm_connector *connector) 
	/* Let userspace know we have a new connector */

	drm_sysfs_hotplug_event(dev);



	if (connector->ddc)

		return sysfs_create_link(&connector->kdev->kobj,

				 &connector->ddc->dev.kobj, "ddc");

	return 0;

}
@@ -301,6 +305,10 @@ void drm_sysfs_connector_remove(struct drm_connector *connector) 
{

	if (!connector->kdev)

		return;



	if (connector->ddc)

		sysfs_remove_link(&connector->kdev->kobj, "ddc");



	DRM_DEBUG("removing \"%s\" from sysfs\n",

		  connector->name);

include/drm/drm_connector.h

+11 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ struct drm_property; 
struct drm_property_blob;

struct drm_printer;

struct edid;

struct i2c_adapter;



enum drm_connector_force {

	DRM_FORCE_UNSPECIFIED,
@@ -1311,6 +1312,16 @@ struct drm_connector { 
	 * [0]: progressive, [1]: interlaced

	 */

	int audio_latency[2];



	/**

	 * @ddc: associated ddc adapter.

	 * A connector usually has its associated ddc adapter. If a driver uses

	 * this field, then an appropriate symbolic link is created in connector

	 * sysfs directory to make it easy for the user to tell which i2c

	 * adapter is for a particular display.

	 */

	struct i2c_adapter *ddc;



	/**

	 * @null_edid_counter: track sinks that give us all zeros for the EDID.

	 * Needed to workaround some HW bugs where we get all 0s