[RFC 0/5] drm: Add support for tiny LCD displays

[Noralf Trønnes]

This is an attempt at providing a DRM version of drivers/staging/fbtft.
I'm sending this early before cleaning up the code hoping to get some
feedback in case there are better ways to structure this.

The tinydrm module provides a very simplified view of DRM for displays that
has onboard video memory and is connected through a slow bus like SPI/I2C.
A driver using tinydrm has to provide a function that will be called from
the dirtyfb ioctl and optionally drm_panel functions which can be used to
set up the display controller and control backlight.

tinydrm also has fbdev support using fb_deferred_io which is tied in through
the dirtyfb function call. A driver can use the provided deferred work code
to collect dirtyfb calls and schedule display memory updates if it whishes.
The various display controllers can have library modules that handles
display updates.
Display controllers that have a similar register interface as the MIPI DBI/DCS
controllers can use the lcdreg module for register access.

struct tinydrm_device {
	struct drm_device *base;
	u32 width, height;
	struct drm_panel panel;
[...]
	int (*dirtyfb)(struct drm_framebuffer *fb, void *vmem, unsigned flags,
		       unsigned color, struct drm_clip_rect *clips,
		       unsigned num_clips);
};

+------------------------------+---------+
|                              |  fbdev  |
|                  DRM         +------+  |
|                                     |  |
+-------------------------------------+--+
|                                        |
|                tinydrm                 |
|                                        |
+------------------+ .  .  .  .  .  .  . |
|                  |    deferred work    |
|  Display driver  +---------------------+
|                  |  Controller module  |
+------------------+---------------------+
|                 lcdreg                 |
+----------------------------------------+
|     Interface (SPI, I2C, parallel)     |
+----------------------------------------+


Noralf Trønnes (5):
  drm: Add DRM support for tiny LCD displays
  drm/tinydrm: Add lcd register abstraction
  drm/tinydrm/lcdreg: Add SPI support
  drm/tinydrm: Add mipi-dbi support
  drm/tinydrm: Add support for several Adafruit TFT displays

 drivers/gpu/drm/Kconfig                            |   2 +
 drivers/gpu/drm/Makefile                           |   1 +
 drivers/gpu/drm/tinydrm/Kconfig                    |  27 +
 drivers/gpu/drm/tinydrm/Makefile                   |   8 +
 drivers/gpu/drm/tinydrm/adafruit-tft.c             | 256 ++++++++
 drivers/gpu/drm/tinydrm/core/Makefile              |   8 +
 drivers/gpu/drm/tinydrm/core/internal.h            |  43 ++
 drivers/gpu/drm/tinydrm/core/tinydrm-core.c        | 194 ++++++
 drivers/gpu/drm/tinydrm/core/tinydrm-crtc.c        | 203 ++++++
 drivers/gpu/drm/tinydrm/core/tinydrm-deferred.c    | 116 ++++
 drivers/gpu/drm/tinydrm/core/tinydrm-fbdev.c       | 345 ++++++++++
 drivers/gpu/drm/tinydrm/core/tinydrm-framebuffer.c | 112 ++++
 drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c     |  97 +++
 drivers/gpu/drm/tinydrm/core/tinydrm-plane.c       |  50 ++
 drivers/gpu/drm/tinydrm/lcdreg/Kconfig             |   8 +
 drivers/gpu/drm/tinydrm/lcdreg/Makefile            |   5 +
 drivers/gpu/drm/tinydrm/lcdreg/internal.h          |   8 +
 drivers/gpu/drm/tinydrm/lcdreg/lcdreg-core.c       | 190 ++++++
 drivers/gpu/drm/tinydrm/lcdreg/lcdreg-debugfs.c    | 281 ++++++++
 drivers/gpu/drm/tinydrm/lcdreg/lcdreg-spi.c        | 720 +++++++++++++++++++++
 drivers/gpu/drm/tinydrm/mipi-dbi.c                 | 231 +++++++
 include/drm/tinydrm/ili9340.h                      |  85 +++
 include/drm/tinydrm/lcdreg-spi.h                   |  63 ++
 include/drm/tinydrm/lcdreg.h                       | 126 ++++
 include/drm/tinydrm/mipi-dbi.h                     |  24 +
 include/drm/tinydrm/tinydrm.h                      | 142 ++++
 26 files changed, 3345 insertions(+)
 create mode 100644 drivers/gpu/drm/tinydrm/Kconfig
 create mode 100644 drivers/gpu/drm/tinydrm/Makefile
 create mode 100644 drivers/gpu/drm/tinydrm/adafruit-tft.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/Makefile
 create mode 100644 drivers/gpu/drm/tinydrm/core/internal.h
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-core.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-crtc.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-deferred.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-fbdev.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-framebuffer.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
 create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-plane.c
 create mode 100644 drivers/gpu/drm/tinydrm/lcdreg/Kconfig
 create mode 100644 drivers/gpu/drm/tinydrm/lcdreg/Makefile
 create mode 100644 drivers/gpu/drm/tinydrm/lcdreg/internal.h
 create mode 100644 drivers/gpu/drm/tinydrm/lcdreg/lcdreg-core.c
 create mode 100644 drivers/gpu/drm/tinydrm/lcdreg/lcdreg-debugfs.c
 create mode 100644 drivers/gpu/drm/tinydrm/lcdreg/lcdreg-spi.c
 create mode 100644 drivers/gpu/drm/tinydrm/mipi-dbi.c
 create mode 100644 include/drm/tinydrm/ili9340.h
 create mode 100644 include/drm/tinydrm/lcdreg-spi.h
 create mode 100644 include/drm/tinydrm/lcdreg.h
 create mode 100644 include/drm/tinydrm/mipi-dbi.h
 create mode 100644 include/drm/tinydrm/tinydrm.h

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2.2.2