Can anyone detail about the GPIO group, and gpiochip0/1/2 which shown in the dmesg of Jetson TX2? Where are these controllers present?
How to confirm one GPIO belongs to gpio-tegra or gpio-tegra-aon group?
hello jk.t,
you may check kernel init messages for registered GPIOs.
for example,
$ dmesg | grep GPIOs
[ 0.453756] gpiochip_setup_dev: registered GPIOs 320 to 511 on device: gpiochip0 (tegra-gpio)
[ 0.457626] gpiochip_setup_dev: registered GPIOs 256 to 319 on device: gpiochip1 (tegra-gpio-aon)
these were define in the device tree, you may disassembler the dtb file into text file for reference.
for example, $ dtc -I dtb -O dts -o output.txt tegra186-quill-p3310-1000-c03-00-base.dtb
thanks
HI Jerry,
thanks. I got the dmesg and saw them, also I noted the formula to get the GPIO number from pin mux. But I dont understand the philosopy/design behind the range of GPIOs, how may GPIO controllers are ther? why the name gpio-tegra-aon? could you please refer me what documents to I need to refer?
Thanks.
hello jk.t,
please download Tegra X2 TRM for the technical reference manual, you should check [Chapter-8.9 GPIO Controller] for more details.
please also access L4T sources via download center, to check the header files for GPIO definitions.
for example,
$L4T_Sources/r32.4.3/Linux_for_Tegra/source/public/kernel/kernel-4.9/include/dt-bindings/gpio/tegra186-gpio.h