On Mon, Nov 19, 2012 at 09:44:21PM +0100, Rafael J. Wysocki wrote:

So, we want to have acpi_handle (or acpi_node) in addition to of_node in struct
device (to be used in the analogous way plus for the execution of AML methods),
but we don't want all users of device.h to have to include ACPI headers
where the acpi_handle data type is defined.  For this reason, we're using
(void *) as its data type now, which let's say I'm not really happy with.

I've been thinking about that for quite a while, though, and I'm not really
sure what to do about that.  Perhaps we could define something like

struct acpi_dev_node {
#ifdef CONFIG_ACPI
	void *handle;
#endif
};

in device.h and use that as "struct acpi_dev_node acpi_node;" in struct device.
Then, we could add the following macro

#ifdef CONFIG_ACPI
#define ACPI_HANDLE(dev)	((dev)->acpi_node.handle)
#else
#define ACPI_HANDLE(dev)	(NULL)
#endif

and redefine DEVICE_ACPI_HANDLE(dev) as ((acpi_handle)ACPI_HANDLE(dev)).

Then, the $subject patch would add "struct acpi_dev_node acpi_node;" to
struct platform_device_info and use ACPI_HANDLE(dev) instead of accessing
the struct device's field directly.

In addition to struct platform_device_info, we are also going to add
similar to struct i2c_board_info. There already is of_node pointer so I was
thinking to add acpi_handle like you did for platform_device. Type of that
pointer of course needs to be figured out :)