misc: lis3lv02d: convert to use faux_device

The lis3lv02d driver does not need to create a platform device, it only
did so because it was simple to do that in order to get a place in sysfs
to hang some device-specific attributes.  Change it over to use the faux
device instead as this is NOT a real platform device, and it makes the
code even smaller than before.

Cc: Eric Piel <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Link: https://lore.kernel.org/r/2025021028-shortcake-stained-b0a8@gregkh
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: gregkh

drivers/misc/lis3lv02d/lis3lv02d.c

@@ -14,7 +14,6 @@
 #include <linux/dmi.h>
 #include <linux/module.h>
 #include <linux/types.h>
-#include <linux/platform_device.h>
 #include <linux/interrupt.h>
 #include <linux/input.h>
 #include <linux/delay.h>
@@ -230,7 +229,7 @@ static int lis3lv02d_get_pwron_wait(struct lis3lv02d *lis3)
 			return 0;
 		}
 
-		dev_err(&lis3->pdev->dev, "Error unknown odrs-index: %d\n", odr_idx);
+		dev_err(&lis3->fdev->dev, "Error unknown odrs-index: %d\n", odr_idx);
 		return -ENXIO;
 	}
 
@@ -694,7 +693,7 @@ int lis3lv02d_joystick_enable(struct lis3lv02d *lis3)
 	input_dev->phys       = DRIVER_NAME "/input0";
 	input_dev->id.bustype = BUS_HOST;
 	input_dev->id.vendor  = 0;
-	input_dev->dev.parent = &lis3->pdev->dev;
+	input_dev->dev.parent = &lis3->fdev->dev;
 
 	input_dev->open = lis3lv02d_joystick_open;
 	input_dev->close = lis3lv02d_joystick_close;
@@ -855,32 +854,27 @@ static DEVICE_ATTR(position, S_IRUGO, lis3lv02d_position_show, NULL);
 static DEVICE_ATTR(rate, S_IRUGO | S_IWUSR, lis3lv02d_rate_show,
 					    lis3lv02d_rate_set);
 
-static struct attribute *lis3lv02d_attributes[] = {
+static struct attribute *lis3lv02d_attrs[] = {
 	&dev_attr_selftest.attr,
 	&dev_attr_position.attr,
 	&dev_attr_rate.attr,
 	NULL
 };
-
-static const struct attribute_group lis3lv02d_attribute_group = {
-	.attrs = lis3lv02d_attributes
-};
-
+ATTRIBUTE_GROUPS(lis3lv02d);
 
 static int lis3lv02d_add_fs(struct lis3lv02d *lis3)
 {
-	lis3->pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
-	if (IS_ERR(lis3->pdev))
-		return PTR_ERR(lis3->pdev);
+	lis3->fdev = faux_device_create_with_groups(DRIVER_NAME, NULL, NULL, lis3lv02d_groups);
+	if (!lis3->fdev)
+		return -ENODEV;
 
-	platform_set_drvdata(lis3->pdev, lis3);
-	return sysfs_create_group(&lis3->pdev->dev.kobj, &lis3lv02d_attribute_group);
+	faux_device_set_drvdata(lis3->fdev, lis3);
+	return 0;
 }
 
 void lis3lv02d_remove_fs(struct lis3lv02d *lis3)
 {
-	sysfs_remove_group(&lis3->pdev->dev.kobj, &lis3lv02d_attribute_group);
-	platform_device_unregister(lis3->pdev);
+	faux_device_destroy(lis3->fdev);
 	if (lis3->pm_dev) {
 		/* Barrier after the sysfs remove */
 		pm_runtime_barrier(lis3->pm_dev);

drivers/misc/lis3lv02d/lis3lv02d.h

@@ -5,7 +5,7 @@
  *  Copyright (C) 2007-2008 Yan Burman
  *  Copyright (C) 2008-2009 Eric Piel
  */
-#include <linux/platform_device.h>
+#include <linux/device/faux.h>
 #include <linux/input.h>
 #include <linux/regulator/consumer.h>
 #include <linux/miscdevice.h>
@@ -282,7 +282,7 @@ struct lis3lv02d {
 					*/
 
 	struct input_dev	*idev;     /* input device */
-	struct platform_device	*pdev;     /* platform device */
+	struct faux_device	*fdev;     /* faux device */
 	struct regulator_bulk_data regulators[2];
 	atomic_t		count;     /* interrupt count after last read */
 	union axis_conversion	ac;        /* hw -> logical axis */