I'm working with an Orange Pi Zero board powered by OpenWRT with U-Boot (2018.11) and kernel (4.14.93).
I'm trying to implement a recovery mode by inspecting a state of some button during an u-boot phase. This button is connected to a PL4 GPIO line. When Linux gets loaded it's possible to read a state of this GPIO line, but during an u-boot phase result is the same ( 0 ) regardless of a real state of the button (`gpio input pl4`).
As I got from H2+ datasheet, L port is a dedicated port (bank) with all GPIO lines disabled by default, when I try to change value of a configuration register for this port nothing changes - I read it and see that it's the same.
I used both direct memory access (writel and pointer dereferencing) and indirect access - sunxi_gpio_set_cfgpin(). Also I see, indirectly, that the GPIO line is disabled by inspection result of a `gpio st` command.
. How can I turn on any GPIO line on an L port?
. Do I have to change something to *dts / board.c file(s) to make `gpio input pl4` work properly?
Thanks in advance for any help.
