[PATCH 0/3] drm/tiny: ssd16xx: fixes from testing SSD1677 on a PIXPAPER 4.26m

These come out of testing Devarsh's staged SSD1677 support on a Mayqueen
PIXPAPER 4.26m (800x480, SSD1677) driven from a Raspberry Pi 5. They apply
on top of his ssd16xx_7_2 branch [1]; that work is not on the list yet, so
the base here is the staged branch rather than a posted series.

The full test report, including the issues these patches do not address,
is in the thread at [2].

1/3 removes skip_data_entry_mode for SSD1677. With 0x11 never sent, the
reversed RAM window that fb_dirty() programs for 90/180 has no matching
decrement mode, and rotation 180 draws nothing at all while every call
reports success.

2/3 adds an x_mirror flag for panels whose RAM X is scanned in reverse,
which this panel needs - without it the image comes out horizontally
mirrored. Its only user is the pixpaper entry, which is being dropped from
V2, so please take it or leave it as suits; otherwise I will carry it in
the panel series.

3/3 makes a runtime rotation change that has no matching mode fail with
-EINVAL rather than silently corrupting the display. It is a stopgap - the
runtime path itself is still missing the mode swap that probe() does, and
I am happy to look at that as a follow-up.

All three tested on the panel above.

[1] https://github.com/devarsht/linux-next/commits/ssd16xx_7_2/
[2] https://lore.kernel.org/all/[email protected]/

Signed-off-by: LiangCheng Wang <[email protected]>
---
LiangCheng Wang (3):
      drm/tiny: ssd16xx: send data entry mode on SSD1677
      drm/tiny: ssd16xx: support panels whose RAM X order is reversed
      drm/tiny: ssd16xx: reject rotation changes without a matching mode

 drivers/gpu/drm/tiny/ssd16xx.c | 58 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 50 insertions(+), 8 deletions(-)
---
base-commit: db06284c5dcc505ca3687621595c1faa59cbee27
change-id: 20260731-ssd16xx-pixpaper-rpi5-c9e94df4c79f

Best regards,
-- 
LiangCheng Wang <[email protected]>