[PATCH v6 00/10] drm/tegra: Add support for Tegra20/Tegra30 8-bit CPU interface

[Svyatoslav Ryhel <clamor95@gmail.com>]

The display controller in Tegra20/30 SoCs features an 8-bit SPI interface
that closely resembles the MIPI DBI Type B protocol and is referred to as
'8-bit CPU'.

Add MIPI DBI bus support along with 2 DBI Type B panels used in
LG Optimus 2X which work with the 8-bit CPU interface.

Convert rgb, dsi, hdmi and sor to use atomic versions of
drm_encoder_helper_funcs needed for bridge state requesting.
Refactor and expand DC header. Add DC parametrization options
needed for fine tuning by bridges. Make panel parsing by
tegra_output_probe() optional and document optional DSI port. 
Add 8-bit CPU interface in form of a bridge linking to RGB port.

---
Changes in v2:
- convert enums in the dc header into definitions list
- add check in RGB if bridge_state is not NULL, if yes, use default flags
- inverted FLAG_PIXDATA_SAMPLE flag setup logic since default value is set to
  be on NEGEDGE while v1 set default to be on POSEDGE
- 8bit-cpu schema renamed to dbi, removed compaible and set as DC child
- expanded list of required properties
- 8bit-cpu bridge remodelled into dbi interface as DC child
- improve gpio handling
- rework attach to get drvdata from parent
- add panel supplies description
- split panel driver into per-panel drivers
- get DBI interface from the patent directly

I have deliberately left GPIO parsing from device tree since it seems to
be the most convenient and mainstream method of working with GPIOs.


Changes in v3:
- rgb: fix default bus_flags to match original behavior
- dbi-schema: remove compatible from required props
  remove dc@54200000 wrapper from example
  restrict dbi nodes for tegra20/tegra30 only
- dbi: remove unused idx from tegra_dbi_priv
  wrap dbi registration in dc with devm_add_action_or_reset()
  separate dbi into separate object
  export tegra_dc_commit() and trace_dc_readl()/dc_readl()

Changes in v4:
- reorder patches to avoid errors on checking dbi schema
- dbi schema renamed to nvidia,tegra20-dbi for consistency
- fix DC_DISP_V_PULSE0_POSITION_* > DC_DISP_V_PULSE1_POSITION_*
- add MODULE_ALIAS
- swap width and height in panels
- dropped use of init-sequence and gpios
- dbi driver reworked to use only DC to operate pins

Changes in v5:
- added commit modelling DBI bus (suggested by Mikko Perttunen)
- hitachi and lg panels converted to mipi_dbi_driver
- dc header refactored and completed
- added commit documenting DSI controller port
- added commit which converts drm_encoder_helper_funcs to use atomic
  enable/disable
- added commit which makes panel parsing in tegra_output_probe() optional
- dbi command/data converted to enum
- dc com pins are now backed up into drivers private structure
- magic numbers replaced with pin defines
- dropped tegra_dc_readl() from tegra_dbi_pin_set
- tegra_dbi_pin_set() accepts boolean third argument
- tegra_dbi_write() second argument converted to use tegra_dbi_dc_signal enum
- used field_get() to extract pin value
- extended comment regarding init sequence
- nvidia,index > generic reg property
- adjusted tegra_dbi_atomic_enable() to properly handle shadowed registers
- switched to use of_drm_get_bridge_by_endpoint() since panels are auto-wrapped
  into bridge now
- added support for mipi_dbi_host_ops
- added resource managed helper to register DBI device and provided to DC via
  header
- dbi.o built with all other tegra drm files

Changes in v6:
- improved descriptions of new framework
- mipi dbi bus commit authorship was changed with Mikko's permission
- panel commits swapped with mipi dbi panel conversion commits
- fixed tegra_output_probe() for hdmi
- added CONFIG_DRM_MIPI_DBI select into CONFIG_DRM_TEGRA
- devm_drm_bridge_add() moved into bridge probe to avoid possible issues with
  deferred panel probing
- setting LDC pin to V Pulse 1 moved before GPIO pin reconfiguration
- DC_CMD_STATE_ACCESS is set to read and write in tegra_dbi_atomic_disable()
- platform_driver_register() does not error out if driver is registered

Please, keep in mind that this series must be applied on top of
https://gitlab.freedesktop.org/drm/misc/kernel.git (drm-misc-next)
---

Svyatoslav Ryhel (10):
  drm: Add MIPI DBI bus support for MIPI DBI Type A and B
  drm/panel: Convert Hitachi TX10D07VM0BAA to use MIPI DBI bus
  drm/panel: Convert LG LH400WV3-SD04 to use MIPI DBI bus
  drm/tegra: dc: Refactor and expand header
  dt-bindings: display: tegra: Document Tegra20 DSI port
  drm/tegra: Make panel parsing by tegra_output_probe() optional
  drm/tegra: Convert to use atomic versions of drm_encoder_helper_funcs
  drm/tegra: rgb: Parameterize configuration based on bus flags
  dt-bindings: display: tegra: Document 8-bit CPU parallel interface
  drm/tegra: Add support for 8-bit CPU interface

 .../display/tegra/nvidia,tegra20-dbi.yaml     | 113 +++
 .../display/tegra/nvidia,tegra20-dc.yaml      |  22 +
 .../display/tegra/nvidia,tegra20-dsi.yaml     |   6 +
 drivers/gpu/drm/Makefile                      |   2 +-
 drivers/gpu/drm/drm_mipi_dbi_bus.c            | 256 ++++++
 .../drm/panel/panel-hitachi-tx10d07vm0baa.c   | 167 ++--
 drivers/gpu/drm/panel/panel-lg-lh400wv3.c     | 103 +--
 drivers/gpu/drm/tegra/Kconfig                 |   1 +
 drivers/gpu/drm/tegra/Makefile                |   1 +
 drivers/gpu/drm/tegra/dbi.c                   | 576 ++++++++++++
 drivers/gpu/drm/tegra/dc.c                    |  15 +-
 drivers/gpu/drm/tegra/dc.h                    | 859 +++++++++++-------
 drivers/gpu/drm/tegra/drm.h                   |   2 +-
 drivers/gpu/drm/tegra/dsi.c                   |  22 +-
 drivers/gpu/drm/tegra/hdmi.c                  |  22 +-
 drivers/gpu/drm/tegra/output.c                |  52 +-
 drivers/gpu/drm/tegra/rgb.c                   |  72 +-
 drivers/gpu/drm/tegra/sor.c                   |  20 +-
 include/drm/drm_mipi_dbi_bus.h                | 103 +++
 19 files changed, 1851 insertions(+), 563 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-dbi.yaml
 create mode 100644 drivers/gpu/drm/drm_mipi_dbi_bus.c
 create mode 100644 drivers/gpu/drm/tegra/dbi.c
 create mode 100644 include/drm/drm_mipi_dbi_bus.h

-- 
2.53.0