[PATCH] cpuidle: kirkwood: Move out of mach directory, add DT.

On 12/28/2012 08:35 AM, Andrew Lunn wrote:

On Fri, Dec 28, 2012 at 08:18:42AM -0600, Rob Herring wrote:

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On 12/28/2012 06:47 AM, Andrew Lunn wrote:

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Move the Kirkwood cpuidle driver out of arch/arm/mach-kirkwood and
into drivers/cpuidle. Convert the driver into a platform driver and
add a device tree binding. Add a DT node to instantiate the driver for
boards converted to DT, and a platform data for old style boards.

Is this an old comment? I don't see any platform data.

There is no platform data, since all the driver needs is an address of
the DDR control register. The code to create a platform device entry
is in common.c hunk.

So you should say "a platform device for old style boards".

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+		cpuidle at 1418 {
+			compatible = "marvell,kirkwood-cpuidle";
+			reg = <0x1418 0x4>;
+		};
+

This is describing what linux wants, not the hardware. This is a common
problem with cpuidle drivers in that they use shared registers. I don't
have a good solution, but this doesn't belong in DTS.

Do you have a bad solution?

Ha! :) I should say I don't have a clear, obvious solution.

Don't do a platform driver and just check the machine compatible
property which is what I did for highbank. Have the machine code create
the platform device. Not *all* platform devices have to be created based
on the DTB. Create an MFD driver for the whole block of registers.

I could just hard code the address, since its the same for all
kirkwood SoCs. Also, the register is not being used by any other
code on kirkwood, so its not shared.

Then describe it based on the reference manual, but you need to do so
assuming you are using all the other registers. I assume there are other
registers at say 0x1414 or 0x141c. You have to be careful if you create
separate nodes for each register or sub-group of registers. It needs to
work no matter what the OS expectation is.

Rob