Re: [PATCH v3] of/overlay: add of overlay notifications

On Thu, Mar 3, 2016 at 9:10 AM, Alan Tull [off-list ref] wrote:

This patch add of overlay notifications.

When DT overlays are being added, some drivers/subsystems
need to see device tree overlays before the changes go into
the live tree.

This is distinct from reconfig notifiers that are
post-apply or post-remove and which issue very granular
notifications without providing access to the context
of a whole overlay.

The following 4 notificatons are issued:
  OF_OVERLAY_PRE_APPLY
  OF_OVERLAY_POST_APPLY
  OF_OVERLAY_PRE_REMOVE
  OF_OVERLAY_POST_REMOVE

In the case of pre-apply notification, if the notifier
returns error, the overlay will be rejected.

This patch exports two functions for registering/unregistering
notifications:
  of_overlay_notifier_register(struct notifier_block *nb)
  of_overlay_notifier_unregister(struct notifier_block *nb)

The of_mutex is held during these notifications. The
notification data includes pointers to the overlay target
and the overlay:

struct of_overlay_notify_data {
       struct device_node *overlay;
       struct device_node *target;
};

Signed-off-by: Alan Tull <redacted>
---
v2: add missing 'static inline' in of.h
v3: fix build for !OF_OVERLAY in of.h
    add a note in the header that the of_mutex is held
---
 drivers/of/overlay.c |   47 ++++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/of.h   |   25 +++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 1 deletion(-)

This looks fine to me, but apply it when you have a user.

Acked-by: Rob Herring <redacted>

Rob
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