Re: [PATCH 02/44] drm: Add a callback from connector registering

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Jun 15, 2016 at 01:17:47PM +0100, Chris Wilson wrote:
> If a driver wants to more precisely control its initialisation and in
> particular, defer registering its interfaces with userspace until after
> everything is setup, it also needs to defer registering the connectors.
> As some devices need more work during registration, add a callback so
> that drivers can do additional work if required for a connector.
> 
> Correspondingly, we also require an unregister callback.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/drm_crtc.c | 18 ++++++++++++++++--
>  include/drm/drm_crtc.h     | 28 ++++++++++++++++++++++++++++
>  2 files changed, 44 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 4ec35f9e6de5..23dfec41decb 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -990,13 +990,24 @@ int drm_connector_register(struct drm_connector *connector)
>  
>  	ret = drm_debugfs_connector_add(connector);
>  	if (ret) {
> -		drm_sysfs_connector_remove(connector);
> -		return ret;
> +		goto err_sysfs;
> +	}
> +
> +	if (connector->funcs->late_register) {
> +		ret = connector->funcs->late_register(connector);
> +		if (ret)
> +			goto err_debugfs;
>  	}
>  
>  	drm_mode_object_register(connector->dev, &connector->base);
>  
>  	return 0;
> +
> +err_debugfs:
> +	drm_debugfs_connector_remove(connector);
> +err_sysfs:
> +	drm_sysfs_connector_remove(connector);
> +	return ret;
>  }
>  EXPORT_SYMBOL(drm_connector_register);
>  
> @@ -1008,6 +1019,9 @@ EXPORT_SYMBOL(drm_connector_register);
>   */
>  void drm_connector_unregister(struct drm_connector *connector)
>  {
> +	if (connector->funcs->early_unregister)
> +		connector->funcs->early_unregister(connector);
> +
>  	drm_sysfs_connector_remove(connector);
>  	drm_debugfs_connector_remove(connector);
>  }
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 914baa8c161d..0c35b4f73e4c 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -957,6 +957,34 @@ struct drm_connector_funcs {
>  			     uint64_t val);
>  
>  	/**
> +	 * @late_register:
> +	 *
> +	 * This optional hook can be used to register additional userspace
> +	 * interfaces attached to the connector, light backlight control, i2c,
> +	 * DP aux or similar interfaces. It is called late in the driver load
> +	 * sequence from drm_connector_register() when registering all the
> +	 * core drm connector interfaces. Everything added from this callback
> +	 * should be unregistered in the early_unregister callback.
> +	 *
> +	 * Returns:
> +	 *
> +	 * 0 on success, or a negative error code on failure.
> +	 *

I went ocd and removed this line here before applying.
-Daniel

> +	 */
> +	int (*late_register)(struct drm_connector *connector);
> +
> +	/**
> +	 * @early_unregister:
> +	 *
> +	 * This optional hook should be used to unregister the additional
> +	 * userspace interfaces attached to the connector from
> +	 * late_unregister(). It is called from drm_connector_unregister(),
> +	 * early in the driver unload sequence to disable userspace access
> +	 * before data structures are torndown.
> +	 */
> +	void (*early_unregister)(struct drm_connector *connector);
> +
> +	/**
>  	 * @destroy:
>  	 *
>  	 * Clean up connector resources. This is called at driver unload time
> -- 
> 2.8.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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