[RFC 0/5] drm: Add support for tiny LCD displays
Daniel Vetter
daniel at ffwll.ch
Wed Mar 16 14:50:52 UTC 2016
On Wed, Mar 16, 2016 at 02:34:14PM +0100, Noralf Trønnes wrote:
> 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.
fbdev fb_deferred_io should be part of the fbdev helper, not a separate
library. We already have hand-rolled fbdev deferred io in qxl, i915 & udl,
no need to invent yet another one. Well the one in i915 is a bit a hack.
I think the best option would be to extract the code from qxl (since it
already uses a work automatically if needed) and put it into drm_fb_helper.c.
Otherwise the layering goes bust. We already have drm_fb_helper_* hooks
for everything, so only thing to do in drivers is to remove lots of code
\o/
I haven't looked at any of the other parts, just a quick comment on this
part here.
-Daniel
> 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
>
> --
> 2.2.2
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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