doc: anbernic: Update RGxx3 Docs for panel detection

Update the Anbernic RGxx3 documentation to note that panel detection
has been added and how it works.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
This commit is contained in:
Chris Morgan 2023-05-15 11:00:32 -05:00 committed by Kever Yang
parent 12b715bd4f
commit 182d0ba6d6

View file

@ -7,27 +7,36 @@ This allows U-Boot to boot the following Anbernic devices:
- Anbernic RG353M - Anbernic RG353M
- Anbernic RG353P - Anbernic RG353P
- Anbernic RG353PS
- Anbernic RG353V - Anbernic RG353V
- Anbernic RG353VS - Anbernic RG353VS
- Anbernic RG503 - Anbernic RG503
The correct device is detected automatically by comparing ADC values The correct device is detected automatically by comparing ADC values
from ADC channel 1. In the event of an RG353V, an attempt is then made from ADC channel 1. In the event of an RG353V or RG353P, an attempt
to probe for an eMMC and if it fails the device is assumed to be an is then made to probe for an eMMC and if it fails the device is assumed
RG353VS. Based on the detected device, the environment variables to be an RG353VS or RG353PS. Based on the detected device, the
"board", "board_name", and "fdtfile" are set to the correct values environment variables "board", "board_name", and "fdtfile" are set to
corresponding to the board which can be read by a boot script to boot the correct values corresponding to the board which can be read by a
with the correct device tree. boot script to boot with the correct device tree. If the board detected
is not of type RG503 (which currently has only 1 panel revision) a
panel detect is then performed by probing a "dummy" display on the DSI
bus and then querying the display ID. The display ID is then compared
to a table to get the known compatible string for use in Linux, and
this string is saved as an environment variable of "panel".
Please note that there are some versions of the RG353 devices with FDT fixups are performed in the event of an RG353M to change the device
different panels. Panel auto-detection is planned for a later date. name, or in the event the panel detected does not match the devicetree.
This allows Linux to load the correct panel driver without having to
know exactly which panel is used (as there is no user distingushable
way to tell).
Building U-Boot Building U-Boot
--------------- ---------------
.. code-block:: bash .. code-block:: bash
$ export CROSS_COMPILE=aarch64-none-elf- $ export CROSS_COMPILE=aarch64-linux-gnu-
$ export BL31=../rkbin/bin/rk35/rk3568_bl31_v1.34.elf $ export BL31=../rkbin/bin/rk35/rk3568_bl31_v1.34.elf
$ export ROCKCHIP_TPL=../rkbin/bin/rk35/rk3568_ddr_1056MHz_v1.13.bin $ export ROCKCHIP_TPL=../rkbin/bin/rk35/rk3568_ddr_1056MHz_v1.13.bin
$ make anbernic-rgxx3_defconfig $ make anbernic-rgxx3_defconfig
@ -40,7 +49,7 @@ Image installation
------------------ ------------------
Write the ``u-boot-rockchip.bin`` to an SD card offset 32kb from the Write the ``u-boot-rockchip.bin`` to an SD card offset 32kb from the
start. start. Please note that eMMC booting has not been tested at this time.
.. code-block:: bash .. code-block:: bash