On 2013-07-25 18:00, H Hartley Sweeten wrote:
On Thursday, July 25, 2013 7:18 AM, Ian Abbott wrote:
On 2013-07-24 20:14, H Hartley Sweeten wrote:
Make the built-on dio subdevice 0 and the three add-on modules
subdevices 1-3. This allows the driver to consistently use the
ii20k_module_iobase() helper to get the base address needed to
access a the registers used by a given subdevice.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
It's best to avoid reordering the subdevices if you can help it to avoid
screwing with userspace unnecessarily.
This one can be dropped. It was added last just to make the 'iobase' use
consistent.
But...
Shouldn't the userspace be getting the subdevice using
comedi_find_subdevice_by_type()? Or can userspace directly
access a subdevice based on the index?
The original order was:
0 - AO or AI subdevice (module 1)
1 - AO or AI subdevice (module 2)
2 - AO or AI subdevice (module 3)
3 - DIO subdevice (built-in module)
The new order is:
0 - DIO subdevice (built-in module)
1 - AO or AI subdevice (module 1)
2 - AO or AI subdevice (module 2)
3 - AO or AI subdevice (module 3)
So logically the add-on modules are still in the same order. So
the first call of comedi_find_subdevice_by_type() to find the
AO or AI subdevice will still return the module 1 subdevice,
second will return module 2, and third will return module 3.
I see no functional change in the userspace interaction.
It's best not to second guess how much checking the application does or
what assumptions it makes.
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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