From: Andrzej Pietrasiewicz <andrzej.p@collabora.com> mainline inclusion from mainline-v5.14.0-rc7 commit e1a29c6c59553d80a8e17d63494c65a13fb8e241 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I469VQ CVE: NA -------------------------------- 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/d470def6cd661b777faeee67b5838a... Signed-off-by: gouhao <gouhao@uniontech.com> --- drivers/gpu/drm/drm_sysfs.c | 8 ++++++++ include/drm/drm_connector.h | 11 +++++++++++ 2 files changed, 19 insertions(+) diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c index ecb7b3300..52879b001 100644 --- a/drivers/gpu/drm/drm_sysfs.c +++ b/drivers/gpu/drm/drm_sysfs.c @@ -15,6 +15,7 @@ #include <linux/device.h> #include <linux/kdev_t.h> #include <linux/gfp.h> +#include <linux/i2c.h> #include <linux/err.h> #include <linux/export.h> @@ -287,6 +288,9 @@ 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; } @@ -294,6 +298,10 @@ 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); diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 97ea41dc6..d8f4e66fb 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -40,6 +40,7 @@ struct drm_property; struct drm_property_blob; struct drm_printer; struct edid; +struct i2c_adapter; enum drm_connector_force { DRM_FORCE_UNSPECIFIED, @@ -998,6 +999,16 @@ 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 -- 2.20.1