ACPI: battery: Convert the driver to a platform one

While binding drivers directly to struct acpi_device objects allows
basic functionality to be provided, at least in the majority of cases,
there are some problems with it, related to general consistency, sysfs
layout, power management operation ordering, and code cleanliness.

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the ACPI battery 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.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/3187448.CbtlEUcBR6@rafael.j.wysocki

Author: rafaeljw

drivers/acpi/battery.c

@@ -17,6 +17,7 @@
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>
 #include <linux/types.h>
@@ -1208,26 +1209,26 @@ static void sysfs_battery_cleanup(struct acpi_battery *battery)
 	sysfs_remove_battery(battery);
 }
 
-static int acpi_battery_add(struct acpi_device *device)
+static int acpi_battery_probe(struct platform_device *pdev)
 {
-	int result = 0;
+	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 	struct acpi_battery *battery;
-
-	if (!device)
-		return -EINVAL;
+	int result;
 
 	if (device->dep_unmet)
 		return -EPROBE_DEFER;
 
-	battery = devm_kzalloc(&device->dev, sizeof(*battery), GFP_KERNEL);
+	battery = devm_kzalloc(&pdev->dev, sizeof(*battery), GFP_KERNEL);
 	if (!battery)
 		return -ENOMEM;
+
+	platform_set_drvdata(pdev, battery);
+
 	battery->device = device;
 	strscpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
 	strscpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
-	device->driver_data = battery;
 
-	result = devm_mutex_init(&device->dev, &battery->update_lock);
+	result = devm_mutex_init(&pdev->dev, &battery->update_lock);
 	if (result)
 		return result;
 
@@ -1246,7 +1247,7 @@ static int acpi_battery_add(struct acpi_device *device)
 	if (result)
 		goto fail;
 
-	device_init_wakeup(&device->dev, 1);
+	device_init_wakeup(&pdev->dev, true);
 
 	result = acpi_dev_install_notify_handler(device, ACPI_ALL_NOTIFY,
 						 acpi_battery_notify, battery);
@@ -1256,27 +1257,26 @@ static int acpi_battery_add(struct acpi_device *device)
 	return 0;
 
 fail_pm:
-	device_init_wakeup(&device->dev, 0);
+	device_init_wakeup(&pdev->dev, false);
 	unregister_pm_notifier(&battery->pm_nb);
 fail:
 	sysfs_battery_cleanup(battery);
 
 	return result;
 }
 
-static void acpi_battery_remove(struct acpi_device *device)
+static void acpi_battery_remove(struct platform_device *pdev)
 {
-	struct acpi_battery *battery;
+	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
+	struct acpi_battery *battery = platform_get_drvdata(pdev);
 
-	if (!device || !acpi_driver_data(device))
+	if (!device || !battery)
 		return;
 
-	battery = acpi_driver_data(device);
-
 	acpi_dev_remove_notify_handler(device, ACPI_ALL_NOTIFY,
 				       acpi_battery_notify);
 
-	device_init_wakeup(&device->dev, 0);
+	device_init_wakeup(&pdev->dev, false);
 	unregister_pm_notifier(&battery->pm_nb);
 
 	sysfs_battery_cleanup(battery);
@@ -1285,12 +1285,8 @@ static void acpi_battery_remove(struct acpi_device *device)
 /* this is needed to learn about changes made in suspended state */
 static int acpi_battery_resume(struct device *dev)
 {
-	struct acpi_battery *battery;
-
-	if (!dev)
-		return -EINVAL;
+	struct acpi_battery *battery = dev_get_drvdata(dev);
 
-	battery = acpi_driver_data(to_acpi_device(dev));
 	if (!battery)
 		return -EINVAL;
 
@@ -1304,16 +1300,15 @@ static int acpi_battery_resume(struct device *dev)
 
 static DEFINE_SIMPLE_DEV_PM_OPS(acpi_battery_pm, NULL, acpi_battery_resume);
 
-static struct acpi_driver acpi_battery_driver = {
-	.name = "battery",
-	.class = ACPI_BATTERY_CLASS,
-	.ids = battery_device_ids,
-	.ops = {
-		.add = acpi_battery_add,
-		.remove = acpi_battery_remove,
-		},
-	.drv.pm = pm_sleep_ptr(&acpi_battery_pm),
-	.drv.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+static struct platform_driver acpi_battery_driver = {
+	.probe = acpi_battery_probe,
+	.remove = acpi_battery_remove,
+	.driver = {
+		.name = "acpi-battery",
+		.acpi_match_table = battery_device_ids,
+		.pm = pm_sleep_ptr(&acpi_battery_pm),
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
 };
 
 static int __init acpi_battery_init(void)
@@ -1323,12 +1318,12 @@ static int __init acpi_battery_init(void)
 
 	dmi_check_system(bat_dmi_table);
 
-	return acpi_bus_register_driver(&acpi_battery_driver);
+	return platform_driver_register(&acpi_battery_driver);
 }
 
 static void __exit acpi_battery_exit(void)
 {
-	acpi_bus_unregister_driver(&acpi_battery_driver);
+	platform_driver_unregister(&acpi_battery_driver);
 	battery_hook_exit();
 }