Commit 112b2f97 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI: PAD: xen: Convert to a platform driver 

In all cases in which a struct acpi_driver is used for binding a driver
to an ACPI device object, a corresponding platform device is created by
the ACPI core and that device is regarded as a proper representation of
underlying hardware.  Accordingly, a struct platform_driver should be
used by driver code to bind to that device.  There are multiple reasons
why drivers should not bind directly to ACPI device objects [1].

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the Xen ACPI processor aggregator device
(PAD) driver to a platform one.

While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.

Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/

 [1]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/8683270.T7Z3S40VBb@rafael.j.wysocki
parent a56a658f

drivers/xen/xen-acpi-pad.c

+12 −11
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/kernel.h>

#include <linux/types.h>

#include <linux/acpi.h>

#include <linux/platform_device.h>

#include <xen/xen.h>

#include <xen/interface/version.h>

#include <xen/xen-ops.h>
@@ -107,8 +108,9 @@ static void acpi_pad_notify(acpi_handle handle, u32 event, 
	}

}



static int acpi_pad_add(struct acpi_device *device)

static int acpi_pad_probe(struct platform_device *pdev)

{

	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);

	acpi_status status;



	strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
@@ -122,13 +124,13 @@ static int acpi_pad_add(struct acpi_device *device) 
	return 0;

}



static void acpi_pad_remove(struct acpi_device *device)

static void acpi_pad_remove(struct platform_device *pdev)

{

	mutex_lock(&xen_cpu_lock);

	xen_acpi_pad_idle_cpus(0);

	mutex_unlock(&xen_cpu_lock);



	acpi_remove_notify_handler(device->handle,

	acpi_remove_notify_handler(ACPI_HANDLE(&pdev->dev),

		ACPI_DEVICE_NOTIFY, acpi_pad_notify);

}
@@ -137,13 +139,12 @@ static const struct acpi_device_id pad_device_ids[] = { 
	{"", 0},

};



static struct acpi_driver acpi_pad_driver = {

	.name = "processor_aggregator",

	.class = ACPI_PROCESSOR_AGGREGATOR_CLASS,

	.ids = pad_device_ids,

	.ops = {

		.add = acpi_pad_add,

static struct platform_driver acpi_pad_driver = {

	.probe = acpi_pad_probe,

	.remove = acpi_pad_remove,

	.driver = {

		.name = "acpi_processor_aggregator",

		.acpi_match_table = pad_device_ids,

	},

};
@@ -157,6 +158,6 @@ static int __init xen_acpi_pad_init(void) 
	if (!xen_running_on_version_or_later(4, 2))

		return -ENODEV;



	return acpi_bus_register_driver(&acpi_pad_driver);

	return platform_driver_register(&acpi_pad_driver);

}

subsys_initcall(xen_acpi_pad_init);