drm/panel: visionox-vtdr6130: Set prepare_prev_first flag

The DSI host must be enabled for the panel to be initialized in
prepare(). Set the prepare_prev_first flag to guarantee this.

Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240201-visionox-vtdr-prev-first-v2-1-32db52867624@quicinc.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240201-visionox-vtdr-prev-first-v2-1-32db52867624@quicinc.com

drm/panel: Don't store+check prepared/enabled for simple cases

As talked about in commit d2aacaf07395 ("drm/panel: Check for already
prepared/enabled in drm_panel"), we want to remove needless code from
panel drivers that was storing and double-checking the
prepared/enabled state. Even if someone was relying on the
double-check before, that double-check is now in the core and not
needed in individual drivers.

This pile of panel drivers appears to be simple to handle. Based on
code inspection they seemed to be using the prepared/enabled state
simply for double-checking that nothing else in the kernel called them
inconsistently. Now that the core drm_panel is doing the double
checking (and warning) it should be very clear that these devices
don't need their own double-check.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230804140605.RFC.1.Ia54954fd2f7645c1b86597494902973f57feeb71@changeid

drm/panel: vtdr6130: fix unused ret in visionox_vtdr6130_bl_update_status

Fix the following warning:
panel-visionox-vtdr6130.c:249:12: warning: 'ret' is used uninitialized [-Wuninitialized]

Fixes: 9402cde9347e ("drm/panel: vtdr6130: Use 16-bit brightness function")
Reported-by: Daniel Vetter <daniel@ffwll.ch>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230119-topic-sm8550-vtdr6130-fixup-v1-1-82c4fb008138@linaro.org

drm/panel: vtdr6130: Use 16-bit brightness function

This panel communicates brightness in big endian. This is not a quirk of
the panels themselves, but rather, a part of the MIPI standard. Use the
new mipi_dsi_dcs_set_display_brightness_large() function that properly
handles 16-bit brightness instead of bypassing the brightness functions
entirely.

Signed-off-by: Richard Acayan <mailingradian@gmail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-MTP
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230116224909.23884-4-mailingradian@gmail.com

drm/panel: add visionox vtdr6130 DSI panel driver

Add support for the 1080x2400 Visionox VTDR6130 AMOLED DSI panel
found on the Qualcomm SM8550 MTP board.

By default the the panel is configured to work with DSI compressed
streams, but can work in uncompressed video mode since 1080x2400 in
RGB888 fits in the 4 DSI lanes bandwidth.

While display compression is preferred for performance and power
reasons, let's start with the uncompressed video mode support and
add the DSC support later on.

Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
[narmstrong: moved drm/display/ include file before drm/drm_]
Link: https://patchwork.freedesktop.org/patch/msgid/20230103-topic-sm8550-upstream-vtdr6130-panel-v2-2-dd6200f47a76@linaro.org