On Sun, Nov 10, 2013 at 01:58:42AM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > Modify struct acpi_dev_node to contain a pointer to struct device > ambedded in the struct acpi_device associated with the given device > object (that is, its ACPI companion device) instead of an ACPI handle > corresponding to that struct acpi_device. Introduce two new macros > for manipulating that pointer in a CONFIG_ACPI-safe way, > ACPI_COMPANION() and ACPI_COMPANION_SET(), and rework the > ACPI_HANDLE() macro to take the above changes into account. > Drop the ACPI_HANDLE_SET() macro entirely and rework its users to > use ACPI_COMPANION_SET() instead. For some of them who used to > pass the result of acpi_get_child() directly to ACPI_HANDLE_SET() > introduce a helper routine acpi_preset_companion() doing an > equivalent thing. > > The rationale for using a struct device pointer instead of a > struct acpi_device one as the member of struct acpi_dev_node is > that it allows device.h to avoid including linux/acpi.h which would > introduce quite a bit of compilation overhead for stuff that doesn't > care about ACPI. In turn, moving the macros to linux/acpi.h forces > the stuff that does care about ACPI to include that file as > appropriate anyway. > > The main motivation for doing this is that there are things > represented by struct acpi_device objects that don't have valid > ACPI handles (so called fixed ACPI hardware features, such as > power and sleep buttons) and we would like to create platform > device objects for them and "glue" them to their ACPI companions > in the usual way (which currently is impossible due to the > lack of valid ACPI handles). However, there are more reasons > why it may be useful. > > First, struct device pointers allow of much better type checking > than void pointers which are ACPI handles, so it should be more > difficult to write buggy code using modified struct acpi_dev_node > and the new macros. Second, it should help to reduce the number > of places in which the result of ACPI_HANDLE() is passed to > acpi_bus_get_device() in order to obtain a pointer to the > struct acpi_device associated with the given "physical" device, > because now that pointer can be obtained directly by applying > to_acpi_device() to the result of the ACPI_COMPANION() macro. > Finally, it should make it easier to write generic code that will > build both for CONFIG_ACPI set and unset without adding explicit > compiler directives to it. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > --- > > Hi Everybody, > > First of all, I haven't tested this yet, so caveat emptor. I have compiled > it on x86-64 for CONFIG_ACPI set and unset and I'm going to feed it to the > auto build system shortly in case I overlooked something build-related. > > Please have a look and let me know if you have any problems with this in > principle. If not, I'd like to queue it up for inclusion by the end of > the merge window or in the -rc2 time frame (to avoid collisions with any > big merges), as I'd like to be able to work on top of it during the 3.14 > cycle if possible. At first glance, this looks good to me, thanks for removing that void *, I like this a lot better now. greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
