ACPI: SBS: 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 smart battery subsystem (SBS)
driver to a platform one.

After this conversion, acpi_smbus_hc_probe() does not need to populate the
driver_data pointer of the SMBUS HC platform device's ACPI companion any
more, so update it accordingly.

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/3390477.aeNJFYEL58@rafael.j.wysocki

Author: rafaeljw

drivers/acpi/sbs.c

@@ -19,6 +19,7 @@
 #include <linux/timer.h>
 #include <linux/jiffies.h>
 #include <linux/delay.h>
+#include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/platform_data/x86/apple.h>
 #include <acpi/battery.h>
@@ -95,7 +96,7 @@ struct acpi_sbs {
 
 #define to_acpi_sbs(x) power_supply_get_drvdata(x)
 
-static void acpi_sbs_remove(struct acpi_device *device);
+static void acpi_sbs_remove(struct platform_device *pdev);
 static int acpi_battery_get_state(struct acpi_battery *battery);
 
 static inline int battery_scale(int log)
@@ -628,8 +629,9 @@ static void acpi_sbs_callback(void *context)
 	}
 }
 
-static int acpi_sbs_add(struct acpi_device *device)
+static int acpi_sbs_probe(struct platform_device *pdev)
 {
+	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 	struct acpi_sbs *sbs;
 	int result = 0;
 	int id;
@@ -642,11 +644,12 @@ static int acpi_sbs_add(struct acpi_device *device)
 
 	mutex_init(&sbs->lock);
 
-	sbs->hc = acpi_driver_data(acpi_dev_parent(device));
+	platform_set_drvdata(pdev, sbs);
+
+	sbs->hc = dev_get_drvdata(pdev->dev.parent);
 	sbs->device = device;
 	strscpy(acpi_device_name(device), ACPI_SBS_DEVICE_NAME);
 	strscpy(acpi_device_class(device), ACPI_SBS_CLASS);
-	device->driver_data = sbs;
 
 	result = acpi_charger_add(sbs);
 	if (result && result != -ENODEV)
@@ -670,20 +673,15 @@ static int acpi_sbs_add(struct acpi_device *device)
 	acpi_smbus_register_callback(sbs->hc, acpi_sbs_callback, sbs);
 end:
 	if (result)
-		acpi_sbs_remove(device);
+		acpi_sbs_remove(pdev);
 	return result;
 }
 
-static void acpi_sbs_remove(struct acpi_device *device)
+static void acpi_sbs_remove(struct platform_device *pdev)
 {
-	struct acpi_sbs *sbs;
+	struct acpi_sbs *sbs = platform_get_drvdata(pdev);
 	int id;
 
-	if (!device)
-		return;
-	sbs = acpi_driver_data(device);
-	if (!sbs)
-		return;
 	mutex_lock(&sbs->lock);
 	acpi_smbus_unregister_callback(sbs->hc);
 	for (id = 0; id < MAX_SBS_BAT; ++id)
@@ -697,11 +695,7 @@ static void acpi_sbs_remove(struct acpi_device *device)
 #ifdef CONFIG_PM_SLEEP
 static int acpi_sbs_resume(struct device *dev)
 {
-	struct acpi_sbs *sbs;
-	if (!dev)
-		return -EINVAL;
-	sbs = to_acpi_device(dev)->driver_data;
-	acpi_sbs_callback(sbs);
+	acpi_sbs_callback(dev_get_drvdata(dev));
 	return 0;
 }
 #else
@@ -710,14 +704,14 @@ static int acpi_sbs_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(acpi_sbs_pm, NULL, acpi_sbs_resume);
 
-static struct acpi_driver acpi_sbs_driver = {
-	.name = "sbs",
-	.class = ACPI_SBS_CLASS,
-	.ids = sbs_device_ids,
-	.ops = {
-		.add = acpi_sbs_add,
-		.remove = acpi_sbs_remove,
-		},
-	.drv.pm = &acpi_sbs_pm,
+static struct platform_driver acpi_sbs_driver = {
+	.probe = acpi_sbs_probe,
+	.remove = acpi_sbs_remove,
+	.driver = {
+		.name = "acpi-sbs",
+		.acpi_match_table = sbs_device_ids,
+		.pm = &acpi_sbs_pm,
+	},
 };
-module_acpi_driver(acpi_sbs_driver);
+
+module_platform_driver(acpi_sbs_driver);

drivers/acpi/sbshc.c

@@ -265,8 +265,6 @@ static int acpi_smbus_hc_probe(struct platform_device *pdev)
 	hc->ec = dev_get_drvdata(pdev->dev.parent);
 	hc->offset = (val >> 8) & 0xff;
 	hc->query_bit = val & 0xff;
-	/* This is needed for the SBS driver to work. */
-	device->driver_data = hc;
 
 	acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
 	dev_info(&device->dev, "SBS HC: offset = 0x%0x, query_bit = 0x%0x\n",