From 6cba3fe433415b2549c909ce72601902c8254a83 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Fri, 23 Apr 2021 14:42:55 -0400 Subject: drm/dp: Add backpointer to drm_device in drm_dp_aux This is something that we've wanted for a while now: the ability to actually look up the respective drm_device for a given drm_dp_aux struct. This will also allow us to transition over to using the drm_dbg_*() helpers for debug message printing, as we'll finally have a drm_device to reference for doing so. Note that there is one limitation with this - because some DP AUX adapters exist as platform devices which are initialized independently of their respective DRM devices, one cannot rely on drm_dp_aux->drm_dev to always be non-NULL until drm_dp_aux_register() has been called. We make sure to point this out in the documentation for struct drm_dp_aux. v3: * Add WARN_ON_ONCE() to drm_dp_aux_register() if drm_dev isn't filled out Signed-off-by: Lyude Paul Acked-by: Thierry Reding Link: https://patchwork.freedesktop.org/patch/msgid/20210423184309.207645-4-lyude@redhat.com Reviewed-by: Dave Airlie --- include/drm/drm_dp_helper.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'include/drm') diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 1e85c2021f2f..95efe37ea9ca 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1840,6 +1840,8 @@ struct drm_dp_aux_cec { * @name: user-visible name of this AUX channel and the I2C-over-AUX adapter * @ddc: I2C adapter that can be used for I2C-over-AUX communication * @dev: pointer to struct device that is the parent for this AUX channel + * @drm_dev: pointer to the &drm_device that owns this AUX channel. Beware, this + * may be %NULL before drm_dp_aux_register() has been called. * @crtc: backpointer to the crtc that is currently using this AUX channel * @hw_mutex: internal mutex used for locking transfers * @crc_work: worker that captures CRCs for each frame @@ -1847,7 +1849,11 @@ struct drm_dp_aux_cec { * @transfer: transfers a message representing a single AUX transaction * * The @dev field should be set to a pointer to the device that implements the - * AUX channel. + * AUX channel. As well, the @drm_dev field should be set to the &drm_device + * that will be using this AUX channel as early as possible. For many graphics + * drivers this should happen before drm_dp_aux_init(), however it's perfectly + * fine to set this field later so long as it's assigned before calling + * drm_dp_aux_register(). * * The @name field may be used to specify the name of the I2C adapter. If set to * %NULL, dev_name() of @dev will be used. @@ -1879,6 +1885,7 @@ struct drm_dp_aux { const char *name; struct i2c_adapter ddc; struct device *dev; + struct drm_device *drm_dev; struct drm_crtc *crtc; struct mutex hw_mutex; struct work_struct crc_work; -- cgit v1.2.3