linux-toradex.git/drivers/gpu/drm/drm_bridge.c, branch v6.4

drm/bridge: Document the expected behaviour of DSI host controllers

2022-12-08T08:56:57+00:00

The exact behaviour of DSI host controllers is not specified,
therefore define it.

Signed-off-by: Dave Stevenson 
Reviewed-by: Laurent Pinchart 
Link: https://lore.kernel.org/r/20221205173328.1395350-7-dave.stevenson@raspberrypi.com
Signed-off-by: Maxime Ripard

drm/bridge: Introduce pre_enable_prev_first to alter bridge init order

2022-12-08T08:56:57+00:00

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 
Tested-by: Frieder Schrempf 
Reviewed-by: Frieder Schrempf 
Link: https://lore.kernel.org/r/20221205173328.1395350-5-dave.stevenson@raspberrypi.com
Signed-off-by: Maxime Ripard

drm/bridge: Drop unused drm_bridge_chain functions

2022-12-08T08:56:57+00:00

The drm_bridge_chain_{pre_enable,enable,disable,post_disable} has no
users left and we have atomic variants that should be used.
Drop them so they do not gain new users.

Adjust a few comments to avoid references to the dropped functions.

Signed-off-by: Sam Ravnborg 
Reviewed-by: Maxime Ripard 
Reviewed-by: Laurent Pinchart 
Cc: Laurent Pinchart 
Cc: Maarten Lankhorst 
Cc: Maxime Ripard 
Cc: Thomas Zimmermann 
Cc: Andrzej Hajda 
Cc: Neil Armstrong 
Cc: Robert Foss 
Cc: Daniel Vetter 
Signed-off-by: Dave Stevenson 
Link: https://lore.kernel.org/r/20221205173328.1395350-4-dave.stevenson@raspberrypi.com
Signed-off-by: Maxime Ripard

drm/bridge: Avoid uninitialized variable warning

2022-07-08T11:41:28+00:00

This code works, but technically it uses "num_in_bus_fmts" before it
has been initialized so it leads to static checker warnings and probably
KMEMsan warnings at run time.  Initialize the variable to zero to
silence the warning.

Fixes: f32df58acc68 ("drm/bridge: Add the necessary bits to support bus format negotiation")
Signed-off-by: Dan Carpenter 
Signed-off-by: Maxime Ripard 
Link: https://patchwork.freedesktop.org/patch/msgid/YrrIs3hoGcPVmXc5@kili

drm: Remove linux/media-bus-format.h from drm_crtc.h

2022-07-05T18:15:13+00:00

drm_crtc.h has no need for linux/media-bus-format.h, so don't
include it. Avoids useless rebuilds of the entire universe when
touching linux/media-bus-format.h.

Quite a few placs do currently depend on linux/media-bus-format.h
without actually including it directly. All of those need to be
fixed up.

v2: Deal with ingenic as well
v3: Fix up mxsfb and remaining parts of imx

Acked-by: Sam Ravnborg 
Acked-by: Jani Nikula 
Signed-off-by: Ville Syrjälä 
Link: https://patchwork.freedesktop.org/patch/msgid/20220630195114.17407-4-ville.syrjala@linux.intel.com

drm/bridge: Add devm_drm_bridge_add()

2022-06-02T22:15:10+00:00

This adds a devm managed version of drm_bridge_add(). Like other
"devm" function listed in drm_bridge.h, this function takes an
explicit "dev" to use for the lifetime management. A few notes:
* In general we have a "struct device" for bridges that makes a good
  candidate for where the lifetime matches exactly what we want.
* The "bridge->dev->dev" device appears to be the encoder
  device. That's not the right device to use for lifetime management.

Suggested-by: Dmitry Baryshkov 
Signed-off-by: Douglas Anderson 
Reviewed-by: Dmitry Baryshkov 
Link: https://patchwork.freedesktop.org/patch/msgid/20220510122726.v3.3.Iba4b9bf6c7a1ee5ea2835ad7bd5eaf84d7688520@changeid

drm/bridge: Document the probe issue with MIPI-DSI bridges

2021-09-24T17:25:23+00:00

Interactions between bridges, panels, MIPI-DSI host and the component
framework are not trivial and can lead to probing issues when
implementing a display driver. Let's document the various cases we need
too consider, and the solution to support all the cases.

Signed-off-by: Maxime Ripard 
Reviewed-by: Andrzej Hajda 
Link: https://patchwork.freedesktop.org/patch/msgid/20210910101218.1632297-3-maxime@cerno.tech

drm/bridge: Add documentation sections

2021-09-24T17:25:16+00:00

The bridge documentation overview is quite packed already, and we'll add
some more documentation that isn't part of an overview at all.

Let's add some sections to the documentation to separate each bits.

Reviewed-by: Andrzej Hajda 
Reviewed-by: Sam Ravnborg 
Signed-off-by: Maxime Ripard 
Link: https://patchwork.freedesktop.org/patch/msgid/20210910101218.1632297-2-maxime@cerno.tech

drm/bridge: Move devm_drm_of_get_bridge to bridge/panel.c

2021-09-22T08:44:00+00:00

By depending on devm_drm_panel_bridge_add(), devm_drm_of_get_bridge()
introduces a circular dependency between the modules drm (where
devm_drm_of_get_bridge() ends up) and drm_kms_helper (where
devm_drm_panel_bridge_add() is).

Fix this by moving devm_drm_of_get_bridge() to bridge/panel.c and thus
drm_kms_helper.

Fixes: 87ea95808d53 ("drm/bridge: Add a function to abstract away panels")
Reported-by: Stephen Rothwell 
Signed-off-by: Maxime Ripard 
Tested-by: Heiko Stuebner 
Acked-by: Thomas Zimmermann 
Link: https://patchwork.freedesktop.org/patch/msgid/20210917180925.2602266-1-maxime@cerno.tech

drm/bridge: Add a function to abstract away panels

2021-09-14T08:39:01+00:00

Display drivers so far need to have a lot of boilerplate to first
retrieve either the panel or bridge that they are connected to using
drm_of_find_panel_or_bridge(), and then either deal with each with ad-hoc
functions or create a drm panel bridge through drm_panel_bridge_add.

In order to reduce the boilerplate and hopefully create a path of least
resistance towards using the DRM panel bridge layer, let's create the
function devm_drm_of_get_bridge() to reduce that boilerplate.

Signed-off-by: Maxime Ripard 
Reviewed-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20210910130941.1740182-2-maxime@cerno.tech