Apple SPI properties

While the rest of the world has standardized on _DSD as the way to store
device properties in AML (introduced with ACPI 5.1 in 2014), Apple has been using a custom _DSM to achieve the same for much longer (ever since
they switched from DeviceTree-based PowerPC to Intel in 2005, verified with MacOS X 10.4.11).

The theory of operation on macOS is as
follows:  AppleACPIPlatform.kext
invokes mergeEFIproperties() and mergeDSMproperties() for each device to
merge properties conveyed by EFI drivers as well as properties stored in
AML into the I/O Kit registry from which they can be retrieved by drivers.  We've been supporting EFI properties since commit 58c5475aba67
("x86/efi: Retrieve and assign Apple device properties").  The present commit adds support for _DSM properties, thereby completing our support
for Apple device properties.  The _DSM properties are made available under the primary fwnode, the EFI properties under the secondary fwnode.
So for devices which possess both property types, they can all be elegantly accessed with the uniform API in <linux/property.h>.

Until recently we had no need to support _DSM properties, they contained
only uninteresting garbage.  The situation has changed with MacBooks and
MacBook Pros introduced since 2015:  Their keyboard is attached with SPI
instead of USB and the _CRS data which is necessary to initialize the spi driver only contains valid information if OSPM responds "false" to _OSI("Darwin").  If OSPM responds "true", _CRS is empty and the spi driver fails to initialize.  The rationale is very simple, Apple only cares about macOS and Windows:  On Windows, _CRS contains valid data, whereas on macOS it is empty.  Instead, macOS gleans the necessary data
from the _DSM properties.

Since Linux deliberately defaults to responding "true" to _OSI("Darwin"),
we need to emulate macOS' behaviour by initializing the spi driver with
data returned by the _DSM.

An out-of-tree driver for the SPI keyboard exists which currently binds
to the ACPI device, invokes the _DSM, parses the returned package and instantiates an SPI device with the data gleaned from the _DSM:
https://github.com/cb22/macbook12-spi-driver/commit/9a416d699ef4
https://github.com/cb22/macbook12-spi-driver/commit/0c34936ed9a1

By adding support for Apple's _DSM properties in generic ACPI code, the
out-of-tree driver will be able to register as a regular SPI device, significantly reducing its amount of code and improving its chances to be mainlined.

The SPI keyboard will not be the only user of this commit:  E.g. on the
MacBook8,1, the UART-attached Bluetooth device likewise returns empty _CRS data if OSPM returns "true" to _OSI("Darwin").

The _DSM returns a Package whose format unfortunately deviates slightly
from the _DSD spec:  The properties are marshalled up in a single Package
as alternating key/value elements, unlike _DSD which stores them as a Package of 2-element Packages.  The present commit therefore converts the Package to _DSD format and the ACPI core can then treat the data as
if Apple would follow the standard.

Well, except for one small annoyance:  The properties returned by the _DSM only ever have one of two types, Integer or Buffer.  The former is
retrievable as usual with device_property_read_u64(), but the latter is
not part of the _DSD spec and it is not possible to retrieve Buffer properties with the device_property_read_*() functions due to the type checking performed in drivers/acpi/property.c.  It is however possible to retrieve them with acpi_dev_get_property().  Apple is using the Buffer type somewhat sloppily to store null-terminated strings but also
integers.  The real data type is not distinguishable by the ACPI core and the onus is on the caller to use the contents of the Buffer in an appropriate way.

In case Apple moves to _DSD in the future, this commit first checks for
_DSD and falls back to _DSM only if _DSD is not found.

Cc Federico Lorenzi <[email protected]>

Cc Andy Shevchenko <[email protected]>

Tested-by Ronald Tschalär <[email protected]>

Acked-by Mika Westerberg <[email protected]>

Signed-off-by Lukas Wunner <[email protected]>

---
Changes v2 -> v3:
- Use bitmap to keep track of valid properties.  Move to x86/apple.c to avoid cluttering up generic ACPI code. (Andy, Rafael)

 drivers/acpi/Makefile    |   1 +
 drivers/acpi/internal.h  |   6 +++
 drivers/acpi/property.c  |   3 ++
 drivers/acpi/x86/apple.c | 137
+++++++++++++++++++++++++++++++++++++++++++++++

 4 files changed, 147 insertions(+)

 create mode 100644 drivers/acpi/x86/apple.c

drivers/acpi/Makefile +0 -0

index b1aacfc62b1f..90265ab4437a 100644
@@ -50,6 +50,7 @@ acpi-$(CONFIG_ACPI_REDUCED_HARDWARE_ONLY) += evged.o

 acpi-y += sysfs.o
 acpi-y += property.o
 acpi-$(CONFIG_X86) += acpi_cmos_rtc.o
+acpi-$(CONFIG_X86) += x86/apple.o
 acpi-$(CONFIG_X86) += x86/utils.o
 acpi-$(CONFIG_DEBUG_FS) += debugfs.o
 acpi-$(CONFIG_ACPI_NUMA) += numa.o

drivers/acpi/internal.h +0 -0

index be79f7db1850..79ee29777909 100644
@@ -229,6 +229,12 @@ static inline void suspend_nvs_restore(void) {}
  void acpi_init_properties(struct acpi_device *adev);
  void acpi_free_properties(struct acpi_device *adev);

drivers/acpi/internal.h +4 -0

+#ifdef CONFIG_X86
+void acpi_extract_apple_properties(struct acpi_device *adev);
+#else
+static inline void acpi_extract_apple_properties(struct acpi_device

*adev) {}

drivers/acpi/internal.h +2 -0

+#endif
+

 /*-------------------------------------------------------------------
-------
  Watchdog
   -------------------------------------------------------------------
------- */

drivers/acpi/property.c +0 -0

index 27a9294c843c..d05f4f97c963 100644
@@ -375,6 +375,9 @@ void acpi_init_properties(struct acpi_device
 *adev)
  	if (acpi_of && !adev->flags.of_compatible_ok)
  		acpi_handle_info(adev->handle,

   ACPI_DT_NAMESPACE_HID " requires 'compatible' property\n");

drivers/acpi/property.c +3 -0

+
+	if (is_apple_system && !adev->data.pointer)
+		acpi_extract_apple_properties(adev);

 }

 static void acpi_destroy_nondev_subnodes(struct list_head *list)

drivers/acpi/x86/apple.c new file +5 -0

new file mode 100644
index 000000000000..bffa38f7460e
@@ -0,0 +1,137 @@
+/*
+ * apple.c - Apple ACPI quirks
+ * Copyright (C) 2017 Lukas Wunner <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or

modify
+ * it under the terms of the GNU General Public License (version 2) as
+ * published by the Free Software Foundation.
+ */

drivers/acpi/x86/apple.c new file +12 -0

+
+#include <linux/acpi.h>
+#include <linux/bitmap.h>
+#include <linux/uuid.h>
+
+/* Apple _DSM device properties GUID */
+static const guid_t apple_prp_guid =
+	GUID_INIT(0xA0B5B7C6, 0x1318, 0x441C,
+		  0xB0, 0xC9, 0xFE, 0x69, 0x5E, 0xAF, 0x94, 0x9B);
+
+/**
+ * acpi_extract_apple_properties - retrieve and convert Apple _DSM

properties
+ * @adev: ACPI device for which to retrieve the properties
+ *
+ * Invoke Apple's custom _DSM once to check the protocol version and once more
+ * to retrieve the properties.  They are marshalled up in a single package as
+ * alternating key/value elements, unlike _DSD which stores them as a package
+ * of 2-element packages.  Convert to _DSD format and make them available under
+ * the primary fwnode.
+ */

drivers/acpi/x86/apple.c new file +8 -0

+void acpi_extract_apple_properties(struct acpi_device *adev)
+{
+	unsigned int i, j = 0, newsize = 0, numprops, numvalid;
+	union acpi_object *props, *newprops;
+	unsigned long *valid = NULL;
+	void *free_space;
+
+	props = acpi_evaluate_dsm_typed(adev->handle,

&apple_prp_guid, 1, 0,

drivers/acpi/x86/apple.c new file +10 -0

+					NULL, ACPI_TYPE_BUFFER);
+	if (!props)
+		return;
+
+	if (!props->buffer.length)
+		goto out_free;
+
+	if (props->buffer.pointer[0] != 3) {
+		acpi_handle_info(adev->handle, FW_INFO
+				 "unsupported properties version

%*ph\n",

drivers/acpi/x86/apple.c new file +1 -0

+				 props->buffer.length, props-

Quoted 1 line

buffer.pointer);

drivers/acpi/x86/apple.c new file +5 -0

+		goto out_free;
+	}
+
+	ACPI_FREE(props);
+	props = acpi_evaluate_dsm_typed(adev->handle,

&apple_prp_guid, 1, 1,

drivers/acpi/x86/apple.c new file +9 -0

+					NULL, ACPI_TYPE_PACKAGE);
+	if (!props)
+		return;
+
+	numprops = props->package.count / 2;
+	if (!numprops)
+		goto out_free;
+
+	valid = kcalloc(BITS_TO_LONGS(numprops), sizeof(long),

GFP_KERNEL);

drivers/acpi/x86/apple.c new file +6 -0

+	if (!valid)
+		goto out_free;
+
+	/* newsize = key length + value length of each tuple */
+	for (i = 0; i < numprops; i++) {
+		union acpi_object *key = &props->package.elements[i *

2];

drivers/acpi/x86/apple.c new file +1 -0

+		union acpi_object *val = &props->package.elements[i *

2 + 1];

drivers/acpi/x86/apple.c new file +16 -0

+
+		if ( key->type != ACPI_TYPE_STRING ||
+		    (val->type != ACPI_TYPE_INTEGER &&
+		     val->type != ACPI_TYPE_BUFFER))
+			continue; /* skip invalid properties */
+
+		__set_bit(i, valid);
+		newsize += key->string.length + 1;
+		if ( val->type == ACPI_TYPE_BUFFER)
+			newsize += val->buffer.length;
+	}
+
+	numvalid = bitmap_weight(valid, numprops);
+	if (numprops > numvalid)
+		acpi_handle_info(adev->handle, FW_INFO
+				 "skipped %u properties: wrong

type\n",

drivers/acpi/x86/apple.c new file +5 -0

+				 numprops - numvalid);
+	if (numvalid == 0)
+		goto out_free;
+
+	/* newsize += top-level package + 3 objects for each

key/value tuple */

drivers/acpi/x86/apple.c new file +1 -0

+	newsize	+= (1 + 3 * numvalid) * sizeof(union

acpi_object);

drivers/acpi/x86/apple.c new file +5 -0

+	newprops = ACPI_ALLOCATE_ZEROED(newsize);
+	if (!newprops)
+		goto out_free;
+
+	/* layout: top-level package | packages | key/value tuples |

strings */

drivers/acpi/x86/apple.c new file +7 -0

+	newprops->type = ACPI_TYPE_PACKAGE;
+	newprops->package.count = numvalid;
+	newprops->package.elements = &newprops[1];
+	free_space = &newprops[1 + 3 * numvalid];
+
+	for_each_set_bit(i, valid, numprops) {
+		union acpi_object *key = &props->package.elements[i *

2];

drivers/acpi/x86/apple.c new file +1 -0

+		union acpi_object *val = &props->package.elements[i *

2 + 1];

drivers/acpi/x86/apple.c new file +1 -0

+		unsigned int k = 1 + numvalid + j * 2; /* index into

newprops */

drivers/acpi/x86/apple.c new file +10 -0

+		unsigned int v = k + 1;
+
+		newprops[1 + j].type = ACPI_TYPE_PACKAGE;
+		newprops[1 + j].package.count = 2;
+		newprops[1 + j].package.elements = &newprops[k];
+
+		newprops[k].type = ACPI_TYPE_STRING;
+		newprops[k].string.length = key->string.length;
+		newprops[k].string.pointer = free_space;
+		memcpy(free_space, key->string.pointer, key-

Quoted 1 line

string.length);

drivers/acpi/x86/apple.c new file +5 -0

+		free_space += key->string.length + 1;
+
+		newprops[v].type = val->type;
+		if (val->type == ACPI_TYPE_INTEGER) {
+			newprops[v].integer.value = val-

Quoted 1 line

integer.value;

drivers/acpi/x86/apple.c new file +2 -0

+		} else {
+			newprops[v].buffer.length = val-

Quoted 1 line

buffer.length;

drivers/acpi/x86/apple.c new file +16 -0

+			newprops[v].buffer.pointer = free_space;
+			memcpy(free_space, val->buffer.pointer,
+			       val->buffer.length);
+			free_space += val->buffer.length;
+		}
+		j++; /* count valid properties */
+	}
+	WARN_ON(free_space != (void *)newprops + newsize);
+
+	adev->data.properties = newprops;
+	adev->data.pointer = newprops;
+
+out_free:
+	ACPI_FREE(props);
+	kfree(valid);
+}

MacBooks and MacBook Pros introduced since 2015 return empty _CRS data for SPI slaves, causing device initialization to fail.  Most of the information that would normally be conveyed via _CRS is available through ACPI device properties instead, so take advantage of them.

The meaning and appropriate usage of the device properties was reverse engineered by Ronald Tschalär and carried over from these commits authored by him:

https://github.com/cb22/macbook12-spi-driver/commit/9a416d699ef4
https://github.com/cb22/macbook12-spi-driver/commit/0c34936ed9a1

According to Ronald, the device properties have the following meaning:

spiSclkPeriod   /* period in ns */
spiWordSize     /* in number of bits */
spiBitOrder     /* 1 = MSB_FIRST, 0 = LSB_FIRST */
spiSPO          /* clock polarity: 0 = low, 1 = high */ spiSPH          /* clock phase: 0 = first, 1 = second */ spiCSDelay      /* delay between cs and receive on reads in 10 us */ resetA2RUsec    /* active-to-receive delay? */ resetRecUsec    /* receive delay? */

Cc Federico Lorenzi <[email protected]>

Reported-by Leif Liddy <[email protected]>

Tested-by Ronald Tschalär <[email protected]>

Acked-by Mark Brown <[email protected]>

Acked-by Mika Westerberg <mika.westerberg-VuQAYsv1563Yd54FQh9/[email protected]>

Signed-off-by Lukas Wunner <lukas-JFq808J9C/[email protected]>

---
Changes v2 -> v3:
- Check buffer length for extra safety.  Rename "o" to "obj", use 32 bit division to calculate max_speed_hz. (Andy)

 drivers/spi/spi.c | 31 +++++++++++++++++++++++++++++++

 1 file changed, 31 insertions(+)

drivers/spi/spi.c +0 -0

index 4fcbb0aa71d3..cce133057700 100644
@@ -1693,6 +1693,35 @@ static void of_register_spi_devices(struct
 spi_controller *ctlr) { }
  #endif

 #ifdef CONFIG_ACPI

drivers/spi/spi.c +9 -0

+static void acpi_spi_parse_apple_properties(struct spi_device *spi)
+{
+	struct acpi_device *dev = ACPI_COMPANION(&spi->dev);
+	const union acpi_object *obj;
+
+	if (!is_apple_system)
+		return;
+
+	if (!acpi_dev_get_property(dev, "spiSclkPeriod",

ACPI_TYPE_BUFFER, &obj)

drivers/spi/spi.c +2 -0

+	    && obj->buffer.length >= 4)
+		spi->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj-

Quoted 1 line

buffer.pointer;

drivers/spi/spi.c +2 -0

+
+	if (!acpi_dev_get_property(dev, "spiWordSize",

ACPI_TYPE_BUFFER, &obj)

drivers/spi/spi.c +4 -0

+	    && obj->buffer.length == 8)
+		spi->bits_per_word = *(u64 *)obj->buffer.pointer;
+
+	if (!acpi_dev_get_property(dev, "spiBitOrder",

ACPI_TYPE_BUFFER, &obj)

drivers/spi/spi.c +1 -0

+	    && obj->buffer.length == 8 && !*(u64 *)obj-

Quoted 1 line

buffer.pointer)

drivers/spi/spi.c +3 -0

+		spi->mode |= SPI_LSB_FIRST;
+
+	if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER,

&obj)

drivers/spi/spi.c +1 -0

+	    && obj->buffer.length == 8 &&  *(u64 *)obj-

Quoted 1 line

buffer.pointer)

drivers/spi/spi.c +3 -0

+		spi->mode |= SPI_CPOL;
+
+	if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER,

&obj)

drivers/spi/spi.c +1 -0

+	    && obj->buffer.length == 8 &&  *(u64 *)obj-

Quoted 1 line

buffer.pointer)

drivers/spi/spi.c +3 -0

+		spi->mode |= SPI_CPHA;
+}
+

 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
 {
  struct spi_device *spi = data;

drivers/spi/spi.c +0 -0

@@ -1766,6 +1795,8 @@ static acpi_status
 acpi_register_spi_device(struct spi_controller *ctlr,
  				     acpi_spi_add_resource, spi);
  	acpi_dev_free_resource_list(&resource_list);

drivers/spi/spi.c +2 -0

+	acpi_spi_parse_apple_properties(spi);
+

  if (ret < 0 || !spi->max_speed_hz) {
  spi_dev_put(spi);
  return AE_OK;

We're about to amend device scan with multiple checks whether we're running on a Mac. Speed that up by performing the DMI match only once and caching the result.

Switch over existing Apple DMI checks, thereby fixing two deficiencies:

* They only match "Apple Inc." but not "Apple Computer, Inc.", which is used by BIOSes released between January 2006 (when the first x86 Macs started shipping) and January 2007 (when the company name changed upon introduction of the iPhone).

* They are now #defined to false on non-x86 arches and can thus be optimized away by the compiler.

Suggested-by Andy Shevchenko <[email protected]>

Signed-off-by Lukas Wunner <[email protected]>

---
Changes v2 -> v3:
- Newly inserted patch in v3 to avoid repeated DMI checks for Apple
hardware: The result of the first DMI check in osi.c is cached. Two other existing DMI checks are converted to use the result. Because one of them is in a module (sbs.ko), the bool is_apple_system needs to be exported. On non-x86, the DMI checks and Apple-specific code are omitted altogether. (Andy, Rafael)

 drivers/acpi/osi.c      |  4 ++++
 drivers/acpi/pci_root.c |  3 +--
 drivers/acpi/sbs.c      | 24 +-----------------------
 include/linux/acpi.h    |  6 ++++++
 4 files changed, 12 insertions(+), 25 deletions(-)

drivers/acpi/osi.c +0 -0

index cd953ae10238..6c253d4006b4 100644

Quoted 5 lines · Lukas Wunner

drivers/acpi/osi.c +0 -0

@@ -258,12 +258,16 @@ bool acpi_osi_is_win8(void)
 EXPORT_SYMBOL(acpi_osi_is_win8);
 

drivers/acpi/osi.c bool acpi_osi_is_win8(void) · line 262

Quoted 3 lines

drivers/acpi/osi.c +2 -0

 #ifdef CONFIG_X86
+bool is_apple_system;
+EXPORT_SYMBOL(is_apple_system);

Maybe prepend the name of this variable with acpi_ to indicate that this is ACPI-specific.

Quoted 6 lines · Rafael J. Wysocki

Quoted 5 lines · Lukas Wunner

drivers/acpi/osi.c +0 -0

@@ -258,12 +258,16 @@ bool acpi_osi_is_win8(void)
 EXPORT_SYMBOL(acpi_osi_is_win8);
 

Quoted 6 lines

drivers/acpi/osi.c bool acpi_osi_is_win8(void) · line 262

Quoted 3 lines

drivers/acpi/osi.c +2 -0

 #ifdef CONFIG_X86
+bool is_apple_system;
+EXPORT_SYMBOL(is_apple_system);

Maybe prepend the name of this variable with acpi_ to indicate that this is ACPI-specific.

It's not really ACPI-specific, osi.c just happens to be the best place to set the variable because the acpi_osi_dmi_table[] is checked very early during boot. So early in fact, that I could even replace the existing Apple DMI check in arch/x86/kernel/early-quirks.c with "is_apple_system".

These non-ACPI files currently contain an Apple DMI check:
arch/x86/kernel/early-quirks.c drivers/pci/quirks.c (2x) drivers/firmware/efi/apple-properties.c drivers/thunderbolt/tb.c drivers/thunderbolt/icm.c

The latter three do not #include <linux/acpi.h> yet. Somehow it feels odd to include that header to check for presence of an Apple system because that's not really ACPI-related.

I guess I could introduce a new <linux/apple.h> but I hate the insane proliferation of additional files in include/linux/.

I could merge the contents of apple_bl.h and apple-gmux.h into that new header to
reduce the number of files a bit.

Struggling to find a solution that's nice and clean. Any ideas?

Quoted 8 lines · Lukas Wunner

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Lukas Wunner

I guess I could introduce a new <linux/apple.h> but I hate the insane
proliferation of additional files in include/linux/.

There is include/linux/platform_data/x86/ so maybe put it in there?

Quoted 5 lines

 I could merge the contents of apple_bl.h and apple-gmux.h into that new header to
reduce the number of files a bit.

Struggling to find a solution that's nice and clean.  Any ideas?

I guess you still want it to work if someone configures the kernel without CONFIG_ACPI, although that's slightly debatable, so the variable should be defined somewhere in the arch code I suppose.

I also guess you could add something like arch/x86/platform/apple/ and put the checks and the variable in there (in which case I'd call it x86_apple_machine or similar).

Then invoke the check from acpi_osi_dmi_table[] code and the early-quirks.c one is only needed for !CONFIG_ACPI.

Quoted 11 lines · Rafael J. Wysocki

Quoted 8 lines · Lukas Wunner

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Lukas Wunner

I guess I could introduce a new <linux/apple.h> but I hate the insane
proliferation of additional files in include/linux/.

There is include/linux/platform_data/x86/ so maybe put it in there?

Just suggested the same :-)

Quoted 10 lines

Quoted 5 lines

I could merge the contents of apple_bl.h and apple-gmux.h into that
new header to
reduce the number of files a bit.

Struggling to find a solution that's nice and clean. Any ideas?

I guess you still want it to work if someone configures the kernel without CONFIG_ACPI, although that's slightly debatable, so the variable should be defined somewhere in the arch code I suppose.

Quoted 3 lines

I also guess you could add something like arch/x86/platform/apple/ and put the checks and the variable in there (in which case I'd call it x86_apple_machine or similar).

I'm not sure if we can use drivers/platform/x86 for this, either agreed way is fine to me.

Quoted 7 lines · Andy Shevchenko

Quoted 4 lines · Rafael J. Wysocki

Quoted 3 lines · Lukas Wunner

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Lukas Wunner

Quoted 7 lines

Quoted 5 lines

Quoted 3 lines

I guess I could introduce a new <linux/apple.h> but I hate the insane
proliferation of additional files in include/linux/.

There is include/linux/platform_data/x86/ so maybe put it in there?

Just suggested the same :-)

Quoted 11 lines

Quoted 11 lines

Quoted 6 lines

I could merge the contents of apple_bl.h and apple-gmux.h into that
new header to
reduce the number of files a bit.

Struggling to find a solution that's nice and clean. Any ideas?

I guess you still want it to work if someone configures the kernel without CONFIG_ACPI, although that's slightly debatable, so the variable should be defined somewhere in the arch code I suppose.

Quoted 6 lines

Quoted 3 lines

I also guess you could add something like arch/x86/platform/apple/ and put the checks and the variable in there (in which case I'd call it x86_apple_machine or similar).

I'm not sure if we can use drivers/platform/x86 for this, either agreed way is fine to me.

No, because of the ACPI involvement. That needs to go under arch/ IMO.

Quoted 1 line · Rafael J. Wysocki

On Friday, July 14, 2017 12:36:19 AM Lukas Wunner wrote:

I guess I could introduce a new <linux/apple.h> but I hate the insane proliferation of additional files in include/linux/.  I could merge the contents of apple_bl.h and apple-gmux.h into that new header to reduce the number of files a bit.

Fabricated devices such as LNXPWRBN lack a handle, causing evaluation of _CCA and _DSD to always fail with AE_BAD_PARAMETER. While that is merely a (negligible) waste of processing power, evaluating a _DSM for them (such as Apple's device properties _DSM which we're about to add) results in an ugly error:

    ACPI: \: failed to evaluate _DSM (0x1001)

Avoid by not evaluating _DSD and the upcoming _DSM for devices without handle.

Cc Andy Shevchenko <[email protected]>

Acked-by Mika Westerberg <[email protected]>

Signed-off-by Lukas Wunner <[email protected]>

---
 drivers/acpi/property.c | 3 +++
 1 file changed, 3 insertions(+)

drivers/acpi/property.c +0 -0

index 9364398204e9..27a9294c843c 100644