Making add-on board for TK1, need some clarification

I’m looking at LCD_BL_EN and LCD_BL_PWM pins (GPIO_PH2 and PH1, respectively), and I’m wondering what is used to control them? is there a “driver” with some interface in /proc, or?

I plan to use these to control backlight of attached panel.

EN_AVDD_LCD, I guess can probably be controlled by writing to PMIC registers, otherwise it gets turned on at power-up and off during sleep/shutdown, correct? On the power sequencing diagram on page 3, it’s not exactly clear what happens with that signal - it seems to be always off.

EN_VDD_BL, What controls this one? Is it off in some power state? Do I need to care about it? It seems to be driven by DAP3_DOUT, which, after a quick look through TRM, I cannot find any mention of what it actually stands for (tho it looks like some kinda I2S-like thing based on the context). If this can be used to enable/disable my wled driver…

What does GPIO_PK2 do on expansion header? (I guess, nothing?)
What is LCD_TE? Is it “touch enable”? (my only guess lacking any other explanation).

I will use +VDD_MUX to power backlight, +3.3V_RUN to power tcon/panel electronics (should I gate it with en_avdd_lcd, or does it matter?).

LCD will be eDP, with 4 lanes in use.

Sorry, I have little knowledge about LCD items, not much I can add.

GPIO_PK2 is just general I/O, and uses sysfs serial number 82 for enable, disable, and various mode settings. The numeric ID for dealing with any given GPIO is listed in kernel source header “arch/arm/mach-tegra/gpio-names.h”.

Back when this original question came out there were very few people who would have experience with these questions. If you can update the question there may be people who can now answer.

The EN_AVDD_LCD,EN_VDD_BL are GPIOs and used to control the power for panel. The sample code would use these named GPIO for panel power sequence control. AVDD_LCD is 3.3v usually, VDD_BL is power rail for backlight. it may 5v~20v depend on the panel.
LCD_TE is tearing effect signal input from LCD panel.
GPIO_PK2 is general I/O.
You need use the dedicated GPIO for sequence control.
The eDP is good to support, DP isn’t support in software on JTK1. Thanks