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

[Flavio Suligoi <f.suligoi@asem.it>]

Hi Mika,

> > > 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")
> 
> If this is PCI device then you need to have _ADR here instead of _HID.

the problem is that the parent bus of this device is not declared in any ACPI table.
The exar chip is on the bus 7 :

07:00.0 Serial controller: Exar Corp. XR17V3521 Dual PCIe UART (rev 03)

and in the _ADR object you can specify device and function only. 
How can I specify the parent bus? It is not simple …
The lspci output is the following:

root@debian:/etc# lspci
00:00.0 Host bridge: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series Host Bridge (rev 0d)
00:02.0 VGA compatible controller: Intel Corporation Device 5a85 (rev 0d)
00:0e.0 Audio device: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series Audio Cluster (rev 0d)
00:0f.0 Communication controller: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series Trusted Execution Engine (rev 0d)
00:12.0 SATA controller: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series SATA AHCI Controller (rev 0d)
00:13.0 PCI bridge: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series PCI Express Port A #1 (rev fd)
00:13.1 PCI bridge: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series PCI Express Port A #2 (rev fd)
00:13.2 PCI bridge: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series PCI Express Port A #3 (rev fd)
00:14.0 PCI bridge: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series PCI Express Port B #1 (rev fd)
00:14.1 PCI bridge: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series PCI Express Port B #2 (rev fd)
00:15.0 USB controller: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series USB xHCI (rev 0d)
00:16.0 Signal processing controller: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series I2C Controller #1 (rev 0d)
00:16.1 Signal processing controller: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series I2C Controller #2 (rev 0d)
00:19.0 Signal processing controller: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series SPI Controller #1 (rev 0d)
00:19.1 Signal processing controller: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series SPI Controller #2 (rev 0d)
00:19.2 Signal processing controller: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series SPI Controller #3 (rev 0d)
00:1f.0 ISA bridge: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series Low Pin Count Interface (rev 0d)
00:1f.1 SMBus: Intel Corporation Atom/Celeron/Pentium Processor N4200/N3350/E3900 Series SMBus Controller (rev 0d)
01:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network Connection (rev 03)
02:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network Connection (rev 03)
04:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network Connection (rev 03)
05:00.0 PCI bridge: Pericom Semiconductor Device 2404 (rev 05)
06:01.0 PCI bridge: Pericom Semiconductor Device 2404 (rev 05)
06:02.0 PCI bridge: Pericom Semiconductor Device 2404 (rev 05)
06:03.0 PCI bridge: Pericom Semiconductor Device 2404 (rev 05)
07:00.0 Serial controller: Exar Corp. XR17V3521 Dual PCIe UART (rev 03)  --- Exar serial port
08:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network Connection (rev 03)
root@debian:/etc#
Thanks,
Flavio