Re: gpio-it87: gpiod_get*() always return -ENOENT

["Alexander Ivanov" <amivanov@xxxxxxxxxxxx>]

On Fri, 18 Aug 2023 09:17 -07:00, Alexander Ivanov <amivanov@xxxxxxxxxxxx> wrote:
> Hello,
>
> Appologies if submitting to wrong list.
>
> I am developing a driver for PCIe-based device that needs to receive 
> external signals through on-board GPIOs. The target platform is 
> Intel-based board and running Fedora 34 kernel 5.11.12-300.fc34.x86_64 
> and has GPIO devices driver by gpio-it87.
>
> # gpiodetect
> gpiochip0 [INT34BB:00] (312 lines)
> gpiochip1 [gpio_it87] (64 lines)
>
> 8 of available 64 lines are connected to a header on the board:
>
> # gpioinfo 1
>         ...
>         line  49:  "it87_gp71"       unused   input  active-high
>         line  50:  "it87_gp72"       unused   input  active-high
>         line  51:  "it87_gp73"       unused   input  active-high
>         line  52:  "it87_gp74"       unused   input  active-high
>         line  53:  "it87_gp75"       unused   input  active-high
>         line  54:  "it87_gp76"       unused   input  active-high
>         line  55:  "it87_gp77"       unused   input  active-high
>         ...
>
> These lines are verified with logic analyzer and `gpioset 1 nn=0|1`
>
> The PCIe device driver defines these lines as:
>
> static struct gpiod_lookup_table gpio_it87_gpios = {
>         .dev_id = "gpio_it87",
>         .table = {
>                 GPIO_LOOKUP("gpio-it87", 48, "it87_gp70", GPIO_ACTIVE_HIGH),
>                 GPIO_LOOKUP("gpio-it87", 49, "it87_gp71", GPIO_ACTIVE_HIGH),
>                 GPIO_LOOKUP("gpio-it87", 50, "it87_gp72", GPIO_ACTIVE_HIGH),
>                 GPIO_LOOKUP("gpio-it87", 51, "it87_gp73", GPIO_ACTIVE_HIGH),
>                 GPIO_LOOKUP("gpio-it87", 52, "it87_gp74", GPIO_ACTIVE_HIGH),
>                 GPIO_LOOKUP("gpio-it87", 53, "it87_gp75", GPIO_ACTIVE_HIGH),
>                 GPIO_LOOKUP("gpio-it87", 54, "it87_gp76", GPIO_ACTIVE_HIGH),
>                 GPIO_LOOKUP("gpio-it87", 55, "it87_gp77", GPIO_ACTIVE_HIGH),
>                 {},
>         },
> };
>
> and then adds them to lookup table, eg.:
>
> gpiod_add_lookup_table(&gpio_it87_gpios);
>
> However, none of those lines are available at
>
> struct desc *gpio = gpiod_get(dev, "it87_gp70", GPIOD_IN);
>
> Above returns -ENOENT for any of those lines.
> I believe it is due to incorrct lookup definions in gpio_it87_gpios 
> above, however, I cannot figure out what is wrong there. 
>


Any suggestions on how to resolve the problem?

Thanks,
--Alex