Re: [PATCH v2 02/13] include/hw: document the device_class_set_parent_* fns

[Mark Cave-Ayland]

On 18/04/2023 17:21, Alex Bennée wrote:

These are useful functions for when you want proper inheritance of
functionality across realize/unrealize calls.
Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
---
  include/hw/qdev-core.h | 27 +++++++++++++++++++++++++++
  1 file changed, 27 insertions(+)

diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index d4bbc30c92..b1d194b561 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -795,9 +795,36 @@ void device_class_set_props(DeviceClass *dc, Property 
*props);
  void device_class_set_parent_reset(DeviceClass *dc,
                                     DeviceReset dev_reset,
                                     DeviceReset *parent_reset);
+
+/**
+ * device_class_set_parent_realize(): set up for chaining realize fns
+ * @dc: The device class
+ * @dev_realize: the device realize function
+ * @parent_realize: somewhere to save the parents realize function
+ *
+ * This is intended to be used when the new realize function will
+ * eventually call its parent realization function during creation.
+ * This requires storing the function call somewhere (usually in the
+ * instance structure) so you can eventually call:

I think this should be the class structure, since it is the only possible location 
for the parent realize() function to exist given that these functions are called from 
the .class_init function.

+ *   my_dev->parent_realize(dev, errp);
+ */
  void device_class_set_parent_realize(DeviceClass *dc,
                                       DeviceRealize dev_realize,
                                       DeviceRealize *parent_realize);
+
+
+/**
+ * device_class_set_parent_unrealize(): set up for chaining unrealize fns
+ * @dc: The device class
+ * @dev_unrealize: the device realize function
+ * @parent_unrealize: somewhere to save the parents unrealize function
+ *
+ * This is intended to be used when the new unrealize function will
+ * eventually call its parent unrealization function during the
+ * unrealize phase. This requires storing the function call somewhere
+ * (usually in the instance structure) so you can eventually call:
+ *   my_dev->parent_unrealize(dev);

And same here of course.

+ */
  void device_class_set_parent_unrealize(DeviceClass *dc,
                                         DeviceUnrealize dev_unrealize,
                                         DeviceUnrealize *parent_unrealize);


ATB,

Mark.