GPIO_V2_LINES_MAX 64

[mfide]

Hello,

I have a AM62 TI SOM module works on Linux 6.12.
One of the gpiochips on it has 92 IOs.
I saw in the libgpiod v2.x library, some functions refer to GPIO_V2_LINES_MAX which is 64.

Does that mean, cannot use the IO numbers higher than 64?

Thanks.

[brgl]

You can request at most 64 lines at once. If you try to request all the lines then you are probably doing something wrong.

[mfide]

Let's say I have a line_config which target only one line. (offset =1, num_offsets=1)
I have another line_config which targets (offset =2, num_offsets=1)
I have another line_config which targets (offset =3, num_offsets=1)
..
I have another line_config which targets (offset =90, num_offsets=1)

Can I call gpiod_chip_request_lines function one by one with all line_configs defined above without releasing the line with gpiod_line_request_release?

Thank you.

[brgl]

Each call to gpiod_chip_request_lines will result in creating a new request file descriptor wrapped by an associated gpiod_line_request object. Each has to be released by calling gpiod_line_request_release(). The rule of thumb is always: one release call for every "create" call.

[brgl]

But yes: you can call gpiod_chip_request_lines() multiple times on the same chip alright.