drm: Add ddc link in sysfs created by drm_connector (e1a29c6c) · Commits · 戴 / test

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:

Andrzej Pietrasiewicz <andrzej.p@collabora.com> Acked-by:

Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by:

Andrzej Hajda <a.hajda@samsung.com> Reviewed-by:

Emil Velikov <emil.velikov@collabora.com> Reviewed-by:

Sam Ravnborg <sam@ravnborg.org> Signed-off-by:

Neil Armstrong <narmstrong@baylibre.com> Link: https://patchwork.freedesktop.org/patch/msgid/d470def6cd661b777faeee67b5838a4623c4010e.1564161140.git.andrzej.p@collabora.com

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

Admin message