[PATCH v4 0/7] drm: Add support for tiny LCD displays

[Noralf Trønnes]

drm: Add support for tiny LCD displays

This is an attempt at providing a DRM version of drivers/staging/fbtft.

The tinydrm library provides a very simplified view of DRM in particular
for tiny displays that has onboard video memory and is connected through
a slow bus like SPI/I2C.

Jani pointed out that the backlight dependency was broken, so since it's
so small and most tinydrm drivers will need it, I just selected it.

The DT rotation property has been moved to display/panel/panel.txt.


Noralf.

Changes since version 3:
- Rebase on new drm_fbdev_cma_init_with_funcs() signature
- Fix backlight dependency by selecting it
- Use #if IS_ENABLED(CONFIG_SPI) instead of #ifdef to handle tristate
- Changed display/display.txt -> display/panel/panel.txt

Changes since version 2:
- Remove fbdev after drm unregister, not before.
- Added Documentation/devicetree/bindings/display/display.txt

Changes since version 1:
- Add tinydrm.rst
- Set tdev->fbdev_cma=NULL on unregister (lastclose is called after that).
- Remove some DRM_DEBUG*()
- Write-combined memory has uncached reads, so speed up by copying/buffering
  one pixel line before conversion.

Changes since RFC v2:
- Rebased on new core helpers
- Don't use drm_panel
- Flush when the framebuffer is changed on the plane
- Add devm_tinydrm_init()
- Fix PRIME support, set vaddr
- Use atomic helpers in suspend/resume
- Add a tinydrm_connector with one display mode
- Set mode_config.preferred_depth and use it for fbdev
- Subclass tinydrm_device in drivers instead of bloating the structure
- The PiTFT display uses a MI0283QT panel, write driver for that instead.
- Drop homegrown lcdreg module, it ended up as a collection of special
  cases.
- Add more documentation

Changes since RFC v1:
- Add fb_deferred_io support to drm_fb_helper and drm_fb_cma_helper,
  and use drm_fb_cma_helper instead.
- Move display pipeline code to drm_simple_kms_helper.
- Don't use (struct drm_driver *)->load().
- Make tinydrm more like a library, exporting the internals.
- Move the struct drm_driver definition from the tinydrm module to the
  driver using a helper macro: TINYDRM_DRM_DRIVER.
- Remove dirtyfb() async code.
- Added support for partial display updates.


Noralf Trønnes (7):
  drm: Add DRM support for tiny LCD displays
  drm/tinydrm: Add helper functions
  drm/tinydrm: Add MIPI DBI support
  of: Add vendor prefix for Multi-Inno
  dt-bindings: display/panel: Add common rotation property
  dt-bindings: Add Multi-Inno MI0283QT binding
  drm/tinydrm: Add support for Multi-Inno MI0283QT display

 .../bindings/display/multi-inno,mi0283qt.txt       |   27 +
 .../devicetree/bindings/display/panel/panel.txt    |    4 +
 .../devicetree/bindings/vendor-prefixes.txt        |    1 +
 Documentation/gpu/index.rst                        |    1 +
 Documentation/gpu/tinydrm.rst                      |   42 +
 MAINTAINERS                                        |    6 +
 drivers/gpu/drm/Kconfig                            |    2 +
 drivers/gpu/drm/Makefile                           |    1 +
 drivers/gpu/drm/tinydrm/Kconfig                    |   21 +
 drivers/gpu/drm/tinydrm/Makefile                   |    7 +
 drivers/gpu/drm/tinydrm/core/Makefile              |    3 +
 drivers/gpu/drm/tinydrm/core/tinydrm-core.c        |  376 ++++++++
 drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c     |  460 +++++++++
 drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c        |  234 +++++
 drivers/gpu/drm/tinydrm/mi0283qt.c                 |  279 ++++++
 drivers/gpu/drm/tinydrm/mipi-dbi.c                 | 1005 ++++++++++++++++++++
 include/drm/tinydrm/ili9341.h                      |   54 ++
 include/drm/tinydrm/mipi-dbi.h                     |  107 +++
 include/drm/tinydrm/tinydrm-helpers.h              |  100 ++
 include/drm/tinydrm/tinydrm.h                      |  115 +++
 20 files changed, 2845 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/multi-inno,mi0283qt.txt
 create mode 100644 Documentation/devicetree/bindings/display/panel/panel.txt
 create mode 100644 Documentation/gpu/tinydrm.rst
 create mode 100644 drivers/gpu/drm/tinydrm/Kconfig
 create mode 100644 drivers/gpu/drm/tinydrm/Makefile
 create mode 100644 drivers/gpu/drm/tinydrm/core/Makefile
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-core.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c
 create mode 100644 drivers/gpu/drm/tinydrm/mi0283qt.c
 create mode 100644 drivers/gpu/drm/tinydrm/mipi-dbi.c
 create mode 100644 include/drm/tinydrm/ili9341.h
 create mode 100644 include/drm/tinydrm/mipi-dbi.h
 create mode 100644 include/drm/tinydrm/tinydrm-helpers.h
 create mode 100644 include/drm/tinydrm/tinydrm.h

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2.10.2