Re: [PATCH] GPIO: Add GPIO support for the ACCES 104-IDIO-16

[Bjorn Helgaas <bhelgaas@xxxxxxxxxx>]

Hi William and Linus,

On Mon, Oct 5, 2015 at 3:29 AM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> On Thu, Oct 1, 2015 at 3:58 AM, William Breathitt Gray
> <vilhelm.gray@xxxxxxxxx> wrote:
>
>> The ACCES 104-IDIO-16 family of PC/104 utility boards
>
> Sounds like a PC104 keyboard :D
>
>> feature 16
>> optically isolated inputs and 16 optically isolated FET solid state
>> outputs. This driver provides GPIO support for these 32 channels of
>> digital I/O. Change-of-State detection interrupts are not supported.
>
> So it has IRQ support but it's not supported yet I take it.
>
>> GPIO 0-15 correspond to digital outputs 0-15, while GPIO 16-31
>> correspond to digital inputs 0-15.
>>
>> Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
>
>> +menu "ISA GPIO expanders"
>
> Interesting submenu. I guess it is proper to have so OK.
>
> Add:
> depends on PCI
>
> As they all will need that, I guess?

Why do they need PCI?  I don't see any PCI interfaces used here.

>> +menuconfig GPIO_104_IDIO_16
>> +       tristate "ACCES 104-IDIO-16 GPIO support"
>> +       help
>> +         Enables GPIO support for the ACCES 104-IDIO-16 family.
>> +
>> +config 104_IDIO_16_BASE
>> +       hex "ACCES 104-IDIO-16 base address"
>> +       depends on GPIO_104_IDIO_16
>> +       default 0x000
>
> This can't be right. PCI devices have their config space for a reason
> I'm told. On other platforms we use device tree or ACPI to set this
> up but PCI is either hotplug or wrong I think.
>
> The driver is full of ISA style inb/outb stuff, I get all confused. Why
> is this not using the PCI infrastructure?

I'm really not familiar with PC/104, but wikipedia claims it only uses
ISA.  Apparently PCI/104-Plus, PCI-104, PCI/104-Express, and PCIe/104
*do* have PCI and/or PCIe, but it looks like the base PC/104 does not.

Bjorn
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