[PATCH v2 0/4] drm/ssd130x: Add support for the Solomon SSD1351 OLED controller

This series adds support for the Solomon SSD1351, a 128x128 65k-color
RGB OLED controller, to the ssd130x DRM driver, and removes the legacy
fbtft fb_ssd1351 driver it supersedes.

v1 [1] was a self-contained ssd1351.c driver. Following Javier's review,
the SSD1351 is instead folded into ssd130x as a new color family, which
also brings 65k color to the existing SSD1331. The work is split as:

  - Patch 1 adds the device tree binding. It was previously posted
    standalone as a v2 [2]; it is folded into this series here, as Conor
    asked, so the binding lands together with the driver and the fbtft
    removal.

  - Patch 2 changes the SSD133X family to drive RGB565 instead of
    RGB332, via a per-variant flag in deviceinfo. The SSD1331 is the
    only current member and gains 65k color from this.

  - Patch 3 adds the SSD1351 as a new SSD135X_FAMILY, reusing the
    SSD133X plane/CRTC and blit/clear helpers. The only data-path
    difference is the explicit Write RAM command (0x5c) the SSD1351
    needs before pixel data; it also gets its own init sequence and a
    longer post-reset settle delay.

  - Patch 4 removes the now-redundant staging fbtft fb_ssd1351 driver.

Testing:

  - The SSD1351 (patches 1 and 3) is tested on hardware.
  - The SSD1331 RGB565 change (patch 2) is compile-tested only; I do not
    currently have a working SSD1331 panel. Javier has kindly offered to
    test it on his SSD1331.

Dependency:

  The SSD1351 reuses ssd133x_update_rect(), which programs the column
  and row *end* address as a relative offset rather than an absolute
  coordinate. This breaks partial updates that do not start at (0,0). A
  separate fix is posted at [3]; until it lands, the SSD1351 shows the
  same partial-redraw artifacts. This series applies independently of
  that fix, but the two are best merged together.

Based on drm-misc-next.

[1] standalone v1 driver:
    https://lore.kernel.org/dri-devel/[email protected]
[2] standalone v2 binding:
    https://lore.kernel.org/dri-devel/[email protected]
[3] ssd132x/ssd133x update_rect end-address fix:
    https://lore.kernel.org/dri-devel/[email protected]

---

Changes since v1:
- Fold the SSD1351 into ssd130x as a new SSD135X family instead of a
  standalone ssd1351.c driver (per Javier).
- Add RGB565 to the SSD133X family, so the SSD1331 also gains 65k color.
- Drop native 256k color (no matching DRM fourcc) and the 0/180
  rotation support, to keep the series focused; both can return later.
- Binding: drop solomon,width / solomon,height (deducible from the
  compatible) and the rotation property (no consumer), per Krzysztof;
  use dt-bindings/gpio/gpio.h flag defines in the example.
- Remove the staging fbtft fb_ssd1351 driver in the same series (per
  Conor).

Amit Barzilai (4):
  dt-bindings: display: Add Solomon SSD1351 OLED controller
  drm/ssd130x: Add RGB565 support to SSD133X family
  drm/ssd130x: Add SSD135X_FAMILY and SSD1351 support
  staging: fbtft: remove fb_ssd1351 driver

 .../bindings/display/solomon,ssd1351.yaml     |  42 +++
 drivers/gpu/drm/solomon/ssd130x-spi.c         |   7 +
 drivers/gpu/drm/solomon/ssd130x.c             | 269 +++++++++++++++---
 drivers/gpu/drm/solomon/ssd130x.h             |  12 +-
 drivers/staging/fbtft/Kconfig                 |   5 -
 drivers/staging/fbtft/Makefile                |   1 -
 drivers/staging/fbtft/fb_ssd1351.c            | 240 ----------------
 7 files changed, 283 insertions(+), 293 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/solomon,ssd1351.yaml
 delete mode 100644 drivers/staging/fbtft/fb_ssd1351.c

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2.54.0