drm/bridge: Introduce pre_enable_prev_first to alter bridge init order
authorDave Stevenson <dave.stevenson@raspberrypi.com>
Mon, 5 Dec 2022 17:33:26 +0000 (17:33 +0000)
committerMaxime Ripard <maxime@cerno.tech>
Thu, 8 Dec 2022 08:56:57 +0000 (09:56 +0100)
commit4fb912e5e19075874379cfcf074d90bd51ebf8ea
tree29b2ac858f1733649399d267f2a932310710fbe7
parent4e910d9d13e122a7a1263cd820d164c409d6a766
drm/bridge: Introduce pre_enable_prev_first to alter bridge init order

DSI sink devices typically want the DSI host powered up and configured
before they are powered up. pre_enable is the place this would normally
happen, but they are called in reverse order from panel/connector towards
the encoder, which is the "wrong" order.

Add a new flag pre_enable_prev_first that any bridge can set
to swap the order of pre_enable (and post_disable) for that and the
immediately previous bridge.
Should the immediately previous bridge also set the
pre_enable_prev_first flag, the previous bridge to that will be called
before either of those which requested pre_enable_prev_first.

eg:
- Panel
- Bridge 1
- Bridge 2 pre_enable_prev_first
- Bridge 3
- Bridge 4 pre_enable_prev_first
- Bridge 5 pre_enable_prev_first
- Bridge 6
- Encoder
Would result in pre_enable's being called as Panel, Bridge 1, Bridge 3,
Bridge 2, Bridge 6, Bridge 5, Bridge 4, Encoder.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Link: https://lore.kernel.org/r/20221205173328.1395350-5-dave.stevenson@raspberrypi.com
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
drivers/gpu/drm/drm_bridge.c
include/drm/drm_bridge.h