platform/x86: acer-wmi: Cleanup accelerometer device handling

Cleanup accelerometer device handling:
-Drop acer_wmi_accel_destroy instead directly call input_unregister_device.
-The information tracked by the CAP_ACCEL flag mirrors acer_wmi_accel_dev
 being NULL. Drop the CAP flag, this is a preparation change for allowing
 users to override the capability flags. Dropping the flag stops users
 from causing a NULL pointer dereference by forcing the capability.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201019185628.264473-3-hdegoede@redhat.com

drivers/platform/x86/acer-wmi.c

@@ -210,7 +210,6 @@ struct hotkey_function_type_aa {
 #define ACER_CAP_BLUETOOTH		BIT(2)
 #define ACER_CAP_BRIGHTNESS		BIT(3)
 #define ACER_CAP_THREEG			BIT(4)
-#define ACER_CAP_ACCEL			BIT(5)
 
 /*
  * Interface type flags
@@ -1509,7 +1508,7 @@ static int acer_gsensor_event(void)
 	struct acpi_buffer output;
 	union acpi_object out_obj[5];
 
-	if (!has_cap(ACER_CAP_ACCEL))
+	if (!acer_wmi_accel_dev)
 		return -1;
 
 	output.length = sizeof(out_obj);
@@ -1883,8 +1882,6 @@ static int __init acer_wmi_accel_setup(void)
 	gsensor_handle = acpi_device_handle(adev);
 	acpi_dev_put(adev);
 
-	interface->capability |= ACER_CAP_ACCEL;
-
 	acer_wmi_accel_dev = input_allocate_device();
 	if (!acer_wmi_accel_dev)
 		return -ENOMEM;
@@ -1910,11 +1907,6 @@ static int __init acer_wmi_accel_setup(void)
 	return err;
 }
 
-static void acer_wmi_accel_destroy(void)
-{
-	input_unregister_device(acer_wmi_accel_dev);
-}
-
 static int __init acer_wmi_input_setup(void)
 {
 	acpi_status status;
@@ -2069,7 +2061,7 @@ static int acer_resume(struct device *dev)
 	if (has_cap(ACER_CAP_BRIGHTNESS))
 		set_u32(data->brightness, ACER_CAP_BRIGHTNESS);
 
-	if (has_cap(ACER_CAP_ACCEL))
+	if (acer_wmi_accel_dev)
 		acer_gsensor_init();
 
 	return 0;
@@ -2259,8 +2251,8 @@ static int __init acer_wmi_init(void)
 error_platform_register:
 	if (wmi_has_guid(ACERWMID_EVENT_GUID))
 		acer_wmi_input_destroy();
-	if (has_cap(ACER_CAP_ACCEL))
-		acer_wmi_accel_destroy();
+	if (acer_wmi_accel_dev)
+		input_unregister_device(acer_wmi_accel_dev);
 
 	return err;
 }
@@ -2270,8 +2262,8 @@ static void __exit acer_wmi_exit(void)
 	if (wmi_has_guid(ACERWMID_EVENT_GUID))
 		acer_wmi_input_destroy();
 
-	if (has_cap(ACER_CAP_ACCEL))
-		acer_wmi_accel_destroy();
+	if (acer_wmi_accel_dev)
+		input_unregister_device(acer_wmi_accel_dev);
 
 	remove_debugfs();
 	platform_device_unregister(acer_platform_device);