[PATCH v2 00/21] omapdrm: Rework the HPD-related operations

Mon Aug 6 20:22:54 UTC 2018

Hello,

This patch series reworks all the HPD-related operations (detection, EDID
read, HPD callback (un)registration and HPD enable/disable) as a step toward
moving from omap_dss_device to drm_bridge.

All HPD-related operations are called by the omapdrm driver on the
omap_dss_device at the end of display pipeline, and the operations are then
handled directly or forwarded to the previous omap_dss_device in the pipeline.
This causes an issue in our quest to move to drm_bridge: there are currently
no HPD-related operations in the drm_bridge API, as they are implemented
internally by bridge drivers for the drm_connector created by the bridges.

To solve this, we will need to extend the drm_bridge API with HPD-related
operations. This patch series is a prototype of such an API, still local to
omap_dss_device for now.

HPD operations can be implemented by multiple components in a display
pipeline. For instance, the DDC bus of an HDMI connector can be wired to an
I2C bus of the SoC, or to the DDC pins of an HDMI encoder. In the first case
the HDMI connector component will provide EDID access, while in the second
case EDID will be read through the HDMI encoder component. Both components
will thus implement the EDID read operation, but on a particular system only
one of them will be able to provide the feature.

Determining which component provides a feature at runtime is thus required,
and is currently performed through recursive calls. This requires all
components to cooperate in a way that can be implemented locally in the
omapdrm driver but would be too complex for the more generic drm_bridge API.
Our solution is to use flags in the omap_dss_device structure to tell, at
runtime, which features are available. The top-level code can then locate the
component providing a particular feature and then use that component directly.

The series starts with removal of dead or unneeded code in patches 01/21 to
03/21. Patch 04/21 prepares for the merge of the omap_dss_driver and
omap_dss_device_ops structures. Patches then 05/21 to 10/21 convert the driver
from the GPIO API to the GPIO descriptors API (drive-by cleanup).

Patch 11/21 is where the real refactoring starts. It moves most operations
from the omap_dss_driver structure to the omap_dss_device_ops structure in
order to simplify code iterating over pipelines. Patch 12/21 defines the
operation flags, and patches 13/21 and 14/21 make use of them to rework the
.detect(), .register_hpd_cb() and .unregister_hpd_cb() operations. Patches
15/21 and 16/21 remove the unneeded .enable_hpd() and .disable_hpd()
operations. Patch 17/21 moves DSS-specific HPD-related code from
omap_dss_device instances to the omapdrm driver, and patch 18/21 reworks the
.read_edid() operation. Patch 19/21 simplifies the component handling in the
CRTC mode set code, and patches 20/21 and 21/21 finally rework the
.set_hdmi_mode() and .set_infoframe() operations.

The series has been tested on the TI AM57xx EVM with kmstest. Module loading
and removal has been tested as well.

For convenience the patches are available at

	git://linuxtv.org/pinchartl/media.git omapdrm/bridge/hpd

Compared to v1, the series has been rebased on top of the latest version of
the base series ("[PATCH v3 00/61] omapdrm: Reverse direction of DSS device
(dis)connect operations"). Please see individual patches for detailed
changelogs.

Laurent Pinchart (21):
  drm/omap: dss: Remove unused omap_dss_driver operations
  drm/omap: dss: Remove omap_dss_driver .[gs]et_mirror operations
  drm/omap: Remove unnecessary display output sanity checks
  drm/omap: Check omap_dss_device type based on the output_type field
  drm/omap: connector-hdmi: Convert to the GPIO descriptors API
  drm/omap: encoder-tfp410: Convert to the GPIO descriptors API
  drm/omap: panel-nec-nl8048hl11: Convert to the GPIO descriptors API
  drm/omap: panel-sony-acx565akm: Convert to the GPIO descriptors API
  drm/omap: panel-tpo-td028ttec1: Drop unneeded linux/gpio.h header
  drm/omap: panel-tpo-td043mtea1: Convert to the GPIO descriptors API
  drm/omap: Move most omap_dss_driver operations to omap_dss_device_ops
  drm/omap: dss: Add device operations flags
  drm/omap: Don't call .detect() operation recursively
  drm/omap: Don't call HPD registration operations recursively
  drm/omap: Remove unneeded safety checks in the HPD operations
  drm/omap: Merge HPD enable operation with HPD callback registration
  drm/omap: Move HPD disconnection handling to omap_connector
  drm/omap: Don't call EDID read operation recursively
  drm/omap: Get from CRTC to display device directly
  drm/omap: Pass both output and display omap_dss_device to encoder init
  drm/omap: Don't call HDMI mode and infoframe operations recursively

 .../gpu/drm/omapdrm/displays/connector-analog-tv.c |   4 +-
 drivers/gpu/drm/omapdrm/displays/connector-dvi.c   |  52 +---
 drivers/gpu/drm/omapdrm/displays/connector-hdmi.c  | 160 +++----------
 drivers/gpu/drm/omapdrm/displays/encoder-tfp410.c  |  51 +---
 .../gpu/drm/omapdrm/displays/encoder-tpd12s015.c   |  79 +-----
 drivers/gpu/drm/omapdrm/displays/panel-dpi.c       |   4 +-
 drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c    |  12 +-
 .../omapdrm/displays/panel-lgphilips-lb035q02.c    |   4 +-
 .../drm/omapdrm/displays/panel-nec-nl8048hl11.c    |  58 +----
 .../drm/omapdrm/displays/panel-sharp-ls037v7dw01.c |   4 +-
 .../drm/omapdrm/displays/panel-sony-acx565akm.c    |  60 ++---
 .../drm/omapdrm/displays/panel-tpo-td028ttec1.c    |   5 +-
 .../drm/omapdrm/displays/panel-tpo-td043mtea1.c    |  81 ++-----
 drivers/gpu/drm/omapdrm/dss/base.c                 |  16 +-
 drivers/gpu/drm/omapdrm/dss/dss.c                  |   5 +-
 drivers/gpu/drm/omapdrm/dss/hdmi4.c                |   4 +-
 drivers/gpu/drm/omapdrm/dss/hdmi5.c                |   4 +-
 drivers/gpu/drm/omapdrm/dss/omapdss.h              |  81 +++----
 drivers/gpu/drm/omapdrm/omap_connector.c           | 265 +++++++++++++--------
 drivers/gpu/drm/omapdrm/omap_connector.h           |   2 +
 drivers/gpu/drm/omapdrm/omap_crtc.c                |  25 +-
 drivers/gpu/drm/omapdrm/omap_drv.c                 |  28 +--
 drivers/gpu/drm/omapdrm/omap_encoder.c             |  49 ++--
 drivers/gpu/drm/omapdrm/omap_encoder.h             |   6 +-
 24 files changed, 386 insertions(+), 673 deletions(-)

-- 
Regards,

Laurent Pinchart