On 04/07/2014 07:48 PM, Matthew Garrett wrote:
On Fri, Apr 04, 2014 at 09:25:50AM -0700, Guenter Roeck wrote:
Is there a clean way to use any of those to implement interrupt support
for this driver ? I thought about hijacking the SCI interrupt by registering
an interrupt handler with acpi_install_sci_handler(), but that would restrict
the driver to kernel only (or the acpi function would have to be exported),
and I have no idea if it would work or, more importantly, if it would be
the best approach to solve the problem, or if the result would be acceptable.
I can figure out the "working" part, but that would not help much if I would
have to carry the patch locally because it is not acceptable for upstream
integration.
You shouldn't need to install an SCI handler - the way the hardware will
generate an SCI is to raise a GPE. If you know which GPE the device
raises (my recollection is that for most Intel chipsets it's GPIO number
+ 0x10) then you can just call acpi_install_gpe_handler(). The problem
Sounds good. Do you by any chance have a pointer to some documentation
explaining this in some more detail ?
is that the firmware may well already be using some of those GPIOs, and
there's no easy way to tell. Checking the interrupt configuration isn't
sufficient, since some of them may just be used as outputs.
The gpio-ich driver already has some magic to detect that condition - I
noticed that I can not request all GPIO pins on all hardware. Either case,
the gpio pins I am interested in are well defined on the hardware I am
dealing with, so I can be sure I won't step on some unexpected use.
Thanks!
Guenter
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