Devices on the Intel Lynxpoint Low Power Subsystem (LPSS) have some
common features that aren't shared with any other platform devices,
including the clock and LTR (Latency Tolerance Reporting) registers.
It is better to handle those features in common code than to bother
device drivers with doing that (I/O functionality-wise the LPSS
devices are generally compatible with other devices that don't
have those special registers and may be handled by the same drivers).
The clock registers of the LPSS devices are now taken care of by
the special clk-x86-lpss driver, but the MMIO mappings used for
accessing those registers can also be used for accessing the LTR
registers on those devices (LTR support for the Lynxpoint LPSS is
going to be added by a subsequent patch). Thus it is convenient
to add a special ACPI scan handler for the Lynxpoint LPSS devices
that will create the MMIO mappings for accessing the clock (and
LTR in the future) registers and will register the LPSS devices'
clocks, so the clk-x86-lpss driver will only need to take care of
the main Lynxpoint LPSS clock.
Introduce a special ACPI scan handler for Intel Lynxpoint LPSS
devices as described above. This also reduces overhead related to
browsing the ACPI namespace in search of the LPSS devices before the
registration of their clocks, removes some LPSS-specific (and
somewhat ugly) code from acpi_platform.c and shrinks the overall code
size slightly.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Currently, the ACPI namespace scanning code creates platform device
objects for ACPI device nodes whose IDs match the contents of the
acpi_platform_device_ids[] table. However, this adds a superfluous
special case into acpi_bus_device_attach() and makes it more
difficult to follow than it has to be. It also will make it more
difficult to implement removal code for those platform device objects
in the future.
For the above reasons, introduce a struct acpi_scan_handler object
for creating platform devices and move the code related to that from
acpi_bus_device_attach() to the .attach() callback of that object.
Also move the acpi_platform_device_ids[] table to acpi_platform.c.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Intel Lynxpoint LPSS peripheral drivers depend on LPSS clock tree being
created in order to function properly. The clock tree is exposed as a
platform driver that binds to a device named 'clk-lpt'.
To support this we modify the acpi_create_platform_device() to take one
additional parameter called flags. This is passed from
acpi_platform_device_ids[] array when acpi_create_platform_device() is
called.
We then introduce a new flag ACPI_PLATFORM_CLK which is used to tell
acpi_create_platform_device() to create the platform clocks as well.
Finally we set the ACPI_PLATFORM_CLK flags for all the Lynxpoint LPSS
devices and make sure that when this flag is set we create the
corresponding clock tree platform device.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We don't use _UID anymore, instead the name will be taken from the
corresponding ACPI device (adev). Fix the obsolete comment.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The internal.h declares the acpi_create_platform_device(). Without
that include we get a following warning:
drivers/acpi/acpi_platform.c:133:24: warning: symbol 'acpi_create_platform_device' was not declared. Should it be static?
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The current platform device creation and registration code in
acpi_create_platform_device() is quite convoluted. This function
takes an ACPI device node as an argument and eventually calls
platform_device_register_resndata() to create and register a
platform device object on the basis of the information contained
in that code. However, it doesn't associate the new platform
device with the ACPI node directly, but instead it relies on
acpi_platform_notify(), called from within device_add(), to find
that ACPI node again with the help of acpi_platform_find_device()
and acpi_platform_match() and then attach the new platform device
to it. This causes an additional ACPI namespace walk to happen and
is clearly suboptimal.
Use the observation that it is now possible to initialize the ACPI
handle of a device before calling device_add() for it to make this
code more straightforward. Namely, add a new field to struct
platform_device_info allowing us to pass the ACPI handle of interest
to platform_device_register_full(), which will then use it to
initialize the new device's ACPI handle before registering it.
This will cause acpi_platform_notify() to use the ACPI handle from
the device structure directly instead of using the .find_device()
routine provided by the device's bus type. In consequence,
acpi_platform_bus, acpi_platform_find_device(), and
acpi_platform_match() are not necessary any more, so remove them.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, whoever wants to use ACPI device resources has to call
acpi_walk_resources() to browse the buffer returned by the _CRS
method for the given device and create filters passed to that
routine to apply to the individual resource items. This generally
is cumbersome, time-consuming and inefficient. Moreover, it may
be problematic if resource conflicts need to be resolved, because
the different users of _CRS will need to do that in a consistent
way. However, if there are resource conflicts, the ACPI core
should be able to resolve them centrally instead of relying on
various users of acpi_walk_resources() to handle them correctly
together.
For this reason, introduce a new function, acpi_dev_get_resources(),
that can be used by subsystems to obtain a list of struct resource
objects corresponding to the ACPI device resources returned by
_CRS and, if necessary, to apply additional preprocessing routine
to the ACPI resources before converting them to the struct resource
format.
Make the ACPI code that creates platform device objects use
acpi_dev_get_resources() for resource processing instead of executing
acpi_walk_resources() twice by itself, which causes it to be much
more straightforward and easier to follow.
In the future, acpi_dev_get_resources() can be extended to meet
the needs of the ACPI PNP subsystem and other users of _CRS in
the kernel.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Use common routines in drivers/acpi/resource.c to parse ACPI device
resources while creating platform device objects.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Using _UID makes the ACPI platform bus code depend on BIOS to get it
right. If it doesn't we fail to create the platform device as the name
should be unique.
The ACPI core already makes a unique name when it first creates the ACPI
device so we can use that same name as the platform device name instead of
trusting that the BIOS sets the _UIDs correctly.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
With ACPI 5 it is now possible to enumerate traditional SoC
peripherals, like serial bus controllers and slave devices behind
them. These devices are typically based on IP-blocks used in many
existing SoC platforms and platform drivers for them may already
be present in the kernel tree.
To make driver "porting" more straightforward, add ACPI support to
the platform bus type. Instead of writing ACPI "glue" drivers for
the existing platform drivers, register the platform bus type with
ACPI to create platform device objects for the drivers and bind the
corresponding ACPI handles to those platform devices.
This should allow us to reuse the existing platform drivers for the
devices in question with the minimum amount of modifications.
This changeset is based on Mika Westerberg's and Mathias Nyman's
work.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
