Hi Andrzej. After reading through the series a few more comments.
1) The subject of this patch could be improved. Consider something like: drm: add ddc link in sysfs created by drm_connector This spells out much better what the patch achieve. 2) The purpsoe of drm_connector.ddc is to provide drm_connector with info to create the symlink. Yet in many follow-up patches the drivers are changed so drm_connector.ddc is their only reference to struct i2c_adapter. But the ownership is not clear here. Who owns the reference to i2c_adapter - and who has the responsibility to call put() on the adapter. Looking at the conversions done then some drivers are converted so they only use drm_connector.ddc, and other drivers have their own reference to i2c_adapter. The latter looks like the correct solution as the ownership of the reference belongs to the driver and not drm_connector. In other words - a conversion where the drivers only assigned drm_connector.ddc (using drm_connector_init_with_ddc()), seems like a more clean design that does not mix up ownership. This is at least how I see it. I did not take this type of look at the patches before. Sorry for providing feedback this late. Sam On Fri, Jul 26, 2019 at 08:37:59AM +0200, Sam Ravnborg wrote: > Hi Andrzej. > > Patch looks good, but one kernel-doc detail. > > On Wed, Jul 24, 2019 at 03:59:23PM +0200, Andrzej Pietrasiewicz wrote: > > 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 <andrze...@collabora.com> > > Acked-by: Daniel Vetter <daniel.vet...@ffwll.ch> > > Reviewed-by: Andrzej Hajda <a.ha...@samsung.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 ad10810bc972..e962a9d45f7e 100644 > > --- a/drivers/gpu/drm/drm_sysfs.c > > +++ b/drivers/gpu/drm/drm_sysfs.c > > @@ -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); > > > > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h > > index 4c30d751487a..33a6fff85fdb 100644 > > --- a/include/drm/drm_connector.h > > +++ b/include/drm/drm_connector.h > > @@ -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; > > To help the reader could you add in the above a reference to > drm_connector_init_with_ddc() sp the reader is told how to init this > field. > > Either add it in PATCH 2 - or merge patch 1 and 2. > > Sam > > > + > > /** > > * @null_edid_counter: track sinks that give us all zeros for the EDID. > > * Needed to workaround some HW bugs where we get all 0s > > -- > > 2.17.1 > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel