Input: applespi - avoid efivars API and invoke EFI services directly

This driver abuses the efivar API, by using a few of its helpers on
entries that were not instantiated by the API itself. This is a problem
as future cleanup work on efivars is complicated by this.

So let's just switch to the get/set variable runtime wrappers directly.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

drivers/input/keyboard/applespi.c

@@ -1597,52 +1597,38 @@ static u32 applespi_notify(acpi_handle gpe_device, u32 gpe, void *context)
 
 static int applespi_get_saved_bl_level(struct applespi_data *applespi)
 {
-	struct efivar_entry *efivar_entry;
+	efi_status_t sts = EFI_NOT_FOUND;
 	u16 efi_data = 0;
-	unsigned long efi_data_len;
-	int sts;
-
-	efivar_entry = kmalloc(sizeof(*efivar_entry), GFP_KERNEL);
-	if (!efivar_entry)
-		return -ENOMEM;
-
-	memcpy(efivar_entry->var.VariableName, EFI_BL_LEVEL_NAME,
-	       sizeof(EFI_BL_LEVEL_NAME));
-	efivar_entry->var.VendorGuid = EFI_BL_LEVEL_GUID;
-	efi_data_len = sizeof(efi_data);
+	unsigned long efi_data_len = sizeof(efi_data);
 
-	sts = efivar_entry_get(efivar_entry, NULL, &efi_data_len, &efi_data);
-	if (sts && sts != -ENOENT)
+	if (efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
+		sts = efi.get_variable(EFI_BL_LEVEL_NAME, &EFI_BL_LEVEL_GUID,
+				       NULL, &efi_data_len, &efi_data);
+	if (sts != EFI_SUCCESS && sts != EFI_NOT_FOUND)
 		dev_warn(&applespi->spi->dev,
-			 "Error getting backlight level from EFI vars: %d\n",
+			 "Error getting backlight level from EFI vars: 0x%lx\n",
 			 sts);
 
-	kfree(efivar_entry);
-
-	return sts ? sts : efi_data;
+	return sts != EFI_SUCCESS ? -ENODEV : efi_data;
 }
 
 static void applespi_save_bl_level(struct applespi_data *applespi,
 				   unsigned int level)
 {
-	efi_guid_t efi_guid;
+	efi_status_t sts = EFI_UNSUPPORTED;
 	u32 efi_attr;
-	unsigned long efi_data_len;
 	u16 efi_data;
-	int sts;
 
-	/* Save keyboard backlight level */
-	efi_guid = EFI_BL_LEVEL_GUID;
 	efi_data = (u16)level;
-	efi_data_len = sizeof(efi_data);
 	efi_attr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS |
 		   EFI_VARIABLE_RUNTIME_ACCESS;
 
-	sts = efivar_entry_set_safe((efi_char16_t *)EFI_BL_LEVEL_NAME, efi_guid,
-				    efi_attr, true, efi_data_len, &efi_data);
-	if (sts)
+	if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE))
+		sts = efi.set_variable(EFI_BL_LEVEL_NAME, &EFI_BL_LEVEL_GUID,
+				       efi_attr, sizeof(efi_data), &efi_data);
+	if (sts != EFI_SUCCESS)
 		dev_warn(&applespi->spi->dev,
-			 "Error saving backlight level to EFI vars: %d\n", sts);
+			 "Error saving backlight level to EFI vars: 0x%lx\n", sts);
 }
 
 static int applespi_probe(struct spi_device *spi)