Platform device id

[Jean Delvare <khali@linux-fr.org>]

Hi Greg, all,

While platform_device.id is a u32, platform_device_add() handles "-1" as
a special id value. This has potential for confusion and bugs. One such
bug was reported to me by David Brownell:

http://lists.lm-sensors.org/pipermail/i2c/2007-September/001787.html

And since then I've found two other drivers  affected (uartlite and
i2c-pxa).

Could we at least make platform_device.id an int so as to clear up the
confusion? I doubt that the id will ever be a large number anyway.

To go one step further, I am questioning the real value of this naming
exception for these "unique" platform devices. On top of the bugs I
mentioned above, it has potential for compatibility breakage: adding a
second device of the same type will rename the first one from "foo" to
"foo.0". It also requires specific checks in many individual platform
drivers. All this, as I understand it, for a purely aesthetic reason. I
don't think this is worth it. Would there be any objection to simply
getting rid of this exception and having all platform devices named
"foo.%d"?

-- 
Jean Delvare