Re: [PATCH v2 2/4] drm/panel: Add driver for DJN HX83112A LCD panel

[Linus Walleij]

On Thu, Jan 11, 2024 at 4:28 PM Luca Weiss <luca.weiss@xxxxxxxxxxxxx> wrote:

> In some internal documentation it says "LCD Driver IC" "HX83112A" and I
> don't see any reference to Truly 5P65 anywhere.

In the Android directory I pointed to I see this file:
HX83112_Android_Driver/Truly_5p65_module_fw/UpdateFW.bat

(Notice the 5p65 fw dir is *inside* the HX82112 dir)

And in that file:
adb push TRULY_5P65_1080_2160_HX83112A_D01C01.bin
/system/etc/firmware/Himax_firmware.bin

Clearly indicating that they are pushing a Truly 5P65 firmware into
the Himax display firmware directory.

To be fair, that is the driver for the touchscreen part of HX83112A,
but ... Truly is a well known manufacturer of display controllers?

But... given that you have a @fairphone.com mal address and
a working relationship with them, can't you just ask?

> On their website they have this sentence:

All OEMs want to look like everything is their own product. It is
business as usual.

Further on the same note since I guess you have a datasheet)
please bring in #defines for the commands (the first byte in the
write sequences, for examples:

+       mipi_dsi_dcs_write_seq(dsi, 0xbd, 0x02);
+       mipi_dsi_dcs_write_seq(dsi, 0xd8,
+                              0xaa, 0xff, 0xff, 0xff, 0xff, 0xff, 0xaa, 0xff,
+                              0xff, 0xff, 0xff, 0xff);
+       mipi_dsi_dcs_write_seq(dsi, 0xbd, 0x03);

Clearly 0xbd is HX83112_CMD_SETREGBANK?
(This is easily spotted from the similar structure in the
existing panel-himax-hx8394.c.) So please add #defines
for all commands you know, especially if you have a datasheet
because we reviewers don't have them and "it's just magic
bytes" isn't very compelling. It adds a lot to understanding.

I strongly suspect other Himax displays such as HX8394 to
be using a Truly controller as well, hence the similarities.

In a datasheet for their TFT800480-84-V1-E display controller
Truly kept the init sequence name of void LCD_INIT_HX8290(void)
for example.

Yours,
Linus Walleij