ACPI / x86: Add acpi_quirk_skip_[i2c_client|serdev]_enumeration() helpers

x86 ACPI boards which ship with only Android as their factory image usually
declare a whole bunch of bogus I2C devs in their ACPI tables and sometimes
there are issues with serdev devices on these boards too, e.g. the resource
points to the wrong serdev_controller.

Instantiating I2C / serdev devs for these bogus devs causes various issues,
e.g. GPIO/IRQ resource conflicts because sometimes drivers do bind to them.
The Android x86 kernel fork shipped on these devices has some special code
to remove the bogus I2C clients (and serdevs are ignored completely).

Introduce acpi_quirk_skip_i2c_client_enumeration() and
acpi_quirk_skip_serdev_enumeration() helpers. Which can be used by the I2C/
serdev code to skip instantiating any I2C or serdev devs on broken boards.

These 2 helpers are added to drivers/acpi/x86/utils.c so that the DMI table
can be shared between the I2C and serdev code.

Note these boards typically do actually have I2C and serdev devices, just
different ones then the ones described in their DSDT. The devices which
are actually present are manually instantiated by the
drivers/platform/x86/x86-android-tablets.c kernel module.

The new helpers are only build if CONFIG_X86_ANDROID_TABLETS is enabled,
otherwise they are empty stubs to not unnecessarily grow the kernel size.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 17f700c9a4f9..88f21780447b 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -622,6 +622,22 @@ static inline bool acpi_device_always_present(struct acpi_device *adev)
 }
 #endif
 
+#if IS_ENABLED(CONFIG_X86_ANDROID_TABLETS)
+bool acpi_quirk_skip_i2c_client_enumeration(struct acpi_device *adev);
+int acpi_quirk_skip_serdev_enumeration(struct device *controller_parent, bool *skip);
+#else
+static inline bool acpi_quirk_skip_i2c_client_enumeration(struct acpi_device *adev)
+{
+	return false;
+}
+static inline int
+acpi_quirk_skip_serdev_enumeration(struct device *controller_parent, bool *skip)
+{
+	*skip = false;
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_PM
 void acpi_pm_wakeup_event(struct device *dev);
 acpi_status acpi_add_pm_notifier(struct acpi_device *adev, struct device *dev,