[PATCH v1 2/2] x86/platform/olpc: xo15: Convert ACPI driver to a platform one

["Rafael J. Wysocki" <rafael@kernel.org>]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

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 olpc-xo15-sci ACPI driver to a platform
one.

After this change, the wakeup source added by the driver will appear
under the platform device used for driver binding, but the sysfs
attribute added by the driver under the ACPI companion of that device
will stay there in case there are utilities in user space expecting it
to be there.

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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 arch/x86/platform/olpc/olpc-xo15-sci.c | 34 ++++++++++++++------------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/arch/x86/platform/olpc/olpc-xo15-sci.c b/arch/x86/platform/olpc/olpc-xo15-sci.c
index 276caf756a9c..e486109e88c8 100644
--- a/arch/x86/platform/olpc/olpc-xo15-sci.c
+++ b/arch/x86/platform/olpc/olpc-xo15-sci.c
@@ -9,6 +9,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/workqueue.h>
+#include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/olpc-ec.h>
 
@@ -136,14 +137,16 @@ static u32 xo15_sci_gpe_handler(acpi_handle gpe_device, u32 gpe, void *context)
 	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
 }
 
-static int xo15_sci_add(struct acpi_device *device)
+static int xo15_sci_probe(struct platform_device *pdev)
 {
+	struct acpi_device *device;
 	unsigned long long tmp;
 	acpi_status status;
 	int r;
 
+	device = ACPI_COMPANION(&pdev->dev);
 	if (!device)
-		return -EINVAL;
+		return -ENODEV;
 
 	strscpy(acpi_device_name(device), XO15_SCI_DEVICE_NAME);
 	strscpy(acpi_device_class(device), XO15_SCI_CLASS);
@@ -160,7 +163,7 @@ static int xo15_sci_add(struct acpi_device *device)
 	if (ACPI_FAILURE(status))
 		return -ENODEV;
 
-	dev_info(&device->dev, "Initialized, GPE = 0x%lx\n", xo15_sci_gpe);
+	dev_info(&pdev->dev, "Initialized, GPE = 0x%lx\n", xo15_sci_gpe);
 
 	r = sysfs_create_file(&device->dev.kobj, &lid_wake_on_close_attr.attr);
 	if (r)
@@ -174,7 +177,7 @@ static int xo15_sci_add(struct acpi_device *device)
 
 	/* Enable wake-on-EC */
 	if (device->wakeup.flags.valid)
-		device_init_wakeup(&device->dev, true);
+		device_init_wakeup(&pdev->dev, true);
 
 	return 0;
 
@@ -184,9 +187,11 @@ static int xo15_sci_add(struct acpi_device *device)
 	return r;
 }
 
-static void xo15_sci_remove(struct acpi_device *device)
+static void xo15_sci_remove(struct platform_device *pdev)
 {
-	device_init_wakeup(&device->dev, false);
+	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
+
+	device_init_wakeup(&pdev->dev, false);
 	acpi_disable_gpe(NULL, xo15_sci_gpe);
 	acpi_remove_gpe_handler(NULL, xo15_sci_gpe, xo15_sci_gpe_handler);
 	cancel_work_sync(&sci_work);
@@ -214,19 +219,18 @@ static const struct acpi_device_id xo15_sci_device_ids[] = {
 	{"", 0},
 };
 
-static struct acpi_driver xo15_sci_drv = {
-	.name = DRV_NAME,
-	.class = XO15_SCI_CLASS,
-	.ids = xo15_sci_device_ids,
-	.ops = {
-		.add = xo15_sci_add,
-		.remove = xo15_sci_remove,
+static struct platform_driver xo15_sci_drv = {
+	.probe = xo15_sci_probe,
+	.remove = xo15_sci_remove,
+	.driver = {
+		.name = DRV_NAME,
+		.acpi_match_table = xo15_sci_device_ids,
+		.pm = &xo15_sci_pm,
 	},
-	.drv.pm = &xo15_sci_pm,
 };
 
 static int __init xo15_sci_init(void)
 {
-	return acpi_bus_register_driver(&xo15_sci_drv);
+	return platform_driver_register(&xo15_sci_drv);
 }
 device_initcall(xo15_sci_init);
-- 
2.51.0