On Fri, Oct 21, 2011 at 11:35:50AM -0600, Stephen Warren wrote:

*_pinmux_init() register the GPIO and pinmux devices so that they're ready
before any other device needs them.

*_pinmux_init() are also called by board-dt.c in order to set up the GPIO
and pinmux configurations. In this case, if we register the devices, they
end up being probed once due to this registration, and a second time due
to a device-tree node (or vice-versa). The second probe fails since the
memory regions are already requested. Besides, we don't actually want the
duplicated devices.

To avoid this duplicate registration, pass a parameter into *_pinmux_init()
indicating whether they should register the device or not. Set this true
for non-DT boards, and false otherwise.

Finally, modify board-dt.c to call the *_pinmux_init() after all devices have
been instantiated from device-tree. This allows the GPIO and pinmux devices
to be instantiated and initialized before calling functions to configure the
hardware.

This has one disadvantage: The pinmux and GPIO initialization now happens
after /all/ devices are instantiated, rather than after just gpio and
pinmux, but before anything else. So the correct HW configuration is not
in place when e.g. the SD/MMC device is probed. Long-term, this should be
solved by doing both:

a) Initializing the HW state from DT nodes during GPIO and pinmux device
   probe.
b) Using the deferred driver probe mechanism, so that drivers can defer
   their probe until after the gpio and pinmux drivers have probed.

Signed-off-by: Stephen Warren <redacted>
---
Grant, Olof, Colin,

What are your thoughts here? Both with and without the patch there are
disadvantages. I'm not sure which one is better...

I'm not a fan of the added argument. Since it's really just a check
whether you are running on a device-tree probed machine or not, adding
a machine_is_{harmony,paz00,seaboard}() check in the same place as the
!is_dt check now will accomplish the same thing.

It would be nice to check for of_machine_is_compatible() instead of the
machine_is_.*() tests, but then you need to ifdef it since it doesn't
evaluate to 0 on CONFIG_OF=n -- for extra bonus, do it that way and add
the empty of_machine_is_compatible() function to include/linux/of.h.


-Olof