Re: How to add the "gpio-line-names" property in a PCI gpio expander

["Rafael J. Wysocki" <rafael@kernel.org>]

CC Mika and Andy who should be more familiar with that problem space than I am.

On Thu, Nov 5, 2020 at 10:46 AM Flavio Suligoi <f.suligoi@asem.it> wrote:
>
> Hi all,
>
> I'm working to introduce the "gpio-line-names" property in the ACPI
> configuration of the BIOS of our x86 boards (we can customize the BIOS of our
> boards).
>
> All is ok for the gpiochips related to the Intel chipset and some I2C gpio
> expanders. I have inserted the _DSD as described in the Linux documentation.
>
> In one of our boards we have an add-on PCI board, with a PCI serial device
> Exar XR17V352. This device also contains 16 gpios.
> The exar device drivers work good, both the "8250_exar" and the "gpio_exar", and
> I can manage the exar's gpios correctly.
> The problem is how to assign the gpio-line-names property to a PCI gpio
> expanders like this.
>
> I tried adding a new device in my ACPI configuration, as:
>
> Device (EXAR)
> {
>     Name (_HID, "13A80352")
>     Name (_STR, Unicode ("STR - Exar GPIOs"))  // _STR: Description String
>
>     Name (_DSD, Package () {
>         ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
>         Package () {
>             Package () {
>                 "gpio-line-names",
>                     Package () {
>                         "exar_0",
>                         "exar_1",
>                         "exar_2",
>                         "exar_3",
>                         ...
>                     }
>                 }
>             }
>     })
> }
>
> but I have no result.
> Does anyone have a suggestion?
>
> Thanks,
>
> Flavio