apu1c led driver

[Larry Baird]

>> Generally rather than specifying the physical addresses as constants in
>> the device driver, the address space and/or IO port resources are
>> managed by the driver for the bus the device sits on.  For something
>> like LEDs and GPIOs that aren't self-identifying devices on a bus and
>> aren't described by ACPI or other system-provided metadata, the 'hints'
>> mechanism gives you a way to provide the resource metadata
>> in /boot/loader.conf.
>> 
>> The device.hints(5) manpage has some helpful info.  Typically you need
>> to provide an 'at' hint to say which bus the device is on.  I'm not sure
>> what's right for your LED/GPIO device; I've only ever used at=isa.  For
>> your device, it looks like you also need maddr/msize hints, then
>> bus_alloc_resource_any() with an rid of 0 and a type of MEMORY should
>> get you a bus_space handle for hardware access.
>
> ISA devices can hardcode ports this way, but this is written as a PCI driver,
> so it isn't going to work.  Larry, you can try changing your driver to be
> an ISA driver by changing the second arg to DRIVER_MODULE() from 'pci' to
> 'isa'.  Is there a way you can probe something or check a BIOS string to
> detect this driver?  If so, you should auto-create a device from an identify
> routine (then you don't need any hints).  Your probe routine should fail for 
> ISA devices with a PNP ID so you don't attach to random things like serial
> ports, etc.

Switching to using an identify routine simplifies things a lot. Thank
you for the hint.

Larry


-- 
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Larry Baird
Global Technology Associates, Inc. 1992-2012 	| http://www.gta.com
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