[DRM] simple analysis of DRM bridge driver call process

This time I'll bring you drm_bridge Driven call process analysis .

1.drm_bridge Structure

struct drm_bridge {
 struct drm_private_obj base;
 struct drm_device *dev;
 struct drm_encoder *encoder;
#ifdef CONFIG_OF
 struct device_node *of_node;//dts node 
#endif
 const struct drm_bridge_timings *timings;
 const struct drm_bridge_funcs *funcs;
 enum drm_bridge_ops ops;
 int type;
 bool interlace_allowed;
 struct i2c_adapter *ddc;
  ...
 void (*hpd_cb)(void *data, enum drm_connector_status status);
 void *hpd_data;
};

• struct drm_private_obj base： Infrastructure of driver private atomic objects , from drm_atomic_private_obj_init() initialization , Its life cycle and DRM The life cycle of the device is related . Among them state Object stores the current atomic state,drm_private_state_funcs Structure management atomic state Replication and destruction of （atomic_duplicate_state and atomic_destroy_state）;

• struct drm_device *dev：drm device drive ,i.MX The drivers on the platform are vivante Provide , Realization gem Management of ;

• struct drm_encoder *encoder：mipi/lvds/hdmi etc. IP Driver object of . for example