I didn't author this patch, just committing it. See below.

Co-authored-by: Patrick Wildt <patrick@blueri.se>

Sigrid Haflínudóttir authored 2 years ago and cinap_lenrek committed 2 years ago

In dual mode (with lcdif and hdmi both used) Linux would end up
with built-in display flashing randomly at the top and otherwise
black screen. Instead of disabling the clocks, shut down the bridge
(SN65DSI86) exactly by spec and leave the clocks be.

Also increase the delay on init to make sure the bridge is up as
sometimes it did not respond in time, causing the display not work
in U-Boot.

The LCDIF needs to be shut down in a particular way.
Disable display clocks, reset and power down mipi dsi.
Disable pwm and edp bridge.
Also stop USB in any case.

Linux kernel mode setting seems to fail to
properly reset the mipi core, causing the
screen to be shifted to the right.

As a work around, we reset the lcdif and
mipi core in a board_quiesce_devices()
function.

GPIO3_20 is the enable for the SN65DSI86,
so power cycling the sdcard would have the
screen turn off.

Co-authored-by: q66 <daniel@octaforge.org>

 - with our boot.scr this is a no-op because flash-kernel stores a
   symlink from /dtb-5.18.0-4-arm64 to /dtbs/${fk_kvers}/${fdtfile}
 - with extlinux.conf under debian-installer only sets fdtdir to /dtbs/
   and then expects u-boot to read /dtbs/freescale/imx8mq-mnt-reform2.dtb
 - without this patch, u-boot will try reading /dtbs/imx8mq-MNT Reform 2.0.dtb
   which doesn't exist

 - this partially reverts b3a8287b which prevented BOOTENV as set by
   config_distro_boot.h being appended to CONFIG_EXTRA_ENV_SETTINGS
 - distro_bootcmd can do everything the nested loop can do:
     * boot from usb
     * arbitrary boot order
     * set arbitrary boot partition
     * search arbitrary list of prefixes
     * load a boot.scr
 - in addition to that, distro_bootcmd:
     * is the standard boot mechanism for distros (see doc/README.distro)
     * thus we can replace hard-to-read custom code
     * works with extlinux.conf (needed for debian-installer)

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

nw2 seems to need this change. Data sheet says 104 ns. This
is a little more.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>