platform/x86: dell-wmi: Update dell_wmi_check_descriptor_buffer() to new model

This converts dell_wmi_check_descriptor_buffer() to the new driver
model interface and puts the interface version in dell_wmi_priv
where it belongs.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

drivers/platform/x86/dell-wmi.c

@@ -48,7 +48,6 @@ MODULE_LICENSE("GPL");
 #define DELL_EVENT_GUID "9DBB5994-A997-11DA-B012-B622A1EF5492"
 #define DELL_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
 
-static u32 dell_wmi_interface_version;
 static bool wmi_requires_smbios_request;
 
 MODULE_ALIAS("wmi:"DELL_EVENT_GUID);
@@ -56,6 +55,7 @@ MODULE_ALIAS("wmi:"DELL_DESCRIPTOR_GUID);
 
 struct dell_wmi_priv {
 	struct input_dev *input_dev;
+	u32 interface_version;
 };
 
 static int __init dmi_matched(const struct dmi_system_id *dmi)
@@ -348,6 +348,7 @@ static void dell_wmi_process_key(struct wmi_device *wdev, int type, int code)
 static void dell_wmi_notify(struct wmi_device *wdev,
 			    union acpi_object *obj)
 {
+	struct dell_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
 	u16 *buffer_entry, *buffer_end;
 	acpi_size buffer_size;
 	int len, i;
@@ -376,7 +377,7 @@ static void dell_wmi_notify(struct wmi_device *wdev,
 	 * So to prevent reading garbage from buffer we will process only first
 	 * one event on devices with WMI interface version 0.
 	 */
-	if (dell_wmi_interface_version == 0 && buffer_entry < buffer_end)
+	if (priv->interface_version == 0 && buffer_entry < buffer_end)
 		if (buffer_end > buffer_entry + buffer_entry[0] + 1)
 			buffer_end = buffer_entry + buffer_entry[0] + 1;
 
@@ -626,61 +627,67 @@ static void dell_wmi_input_destroy(struct wmi_device *wdev)
  * WMI Interface Version     8       4    <version>
  * WMI buffer length        12       4    4096
  */
-static int dell_wmi_check_descriptor_buffer(void)
+static int dell_wmi_check_descriptor_buffer(struct wmi_device *wdev)
 {
-	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
-	union acpi_object *obj;
-	acpi_status status;
+	struct dell_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+	union acpi_object *obj = NULL;
+	struct wmi_device *desc_dev;
 	u32 *buffer;
+	int ret;
 
-	status = wmi_query_block(DELL_DESCRIPTOR_GUID, 0, &out);
-	if (ACPI_FAILURE(status)) {
-		pr_err("Cannot read Dell descriptor buffer - %d\n", status);
-		return status;
+	desc_dev = wmidev_get_other_guid(wdev, DELL_DESCRIPTOR_GUID);
+	if (!desc_dev) {
+		dev_err(&wdev->dev, "Dell WMI descriptor does not exist\n");
+		return -ENODEV;
 	}
 
-	obj = (union acpi_object *)out.pointer;
+	obj = wmidev_block_query(desc_dev, 0);
 	if (!obj) {
-		pr_err("Dell descriptor buffer is empty\n");
-		return -EINVAL;
+		dev_err(&wdev->dev, "failed to read Dell WMI descriptor\n");
+		ret = -EIO;
+		goto out;
 	}
 
 	if (obj->type != ACPI_TYPE_BUFFER) {
-		pr_err("Cannot read Dell descriptor buffer\n");
-		kfree(obj);
-		return -EINVAL;
+		dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
+		ret = -EINVAL;
+		goto out;
 	}
 
 	if (obj->buffer.length != 128) {
-		pr_err("Dell descriptor buffer has invalid length (%d)\n",
+		dev_err(&wdev->dev,
+			"Dell descriptor buffer has invalid length (%d)\n",
 			obj->buffer.length);
 		if (obj->buffer.length < 16) {
-			kfree(obj);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto out;
 		}
 	}
 
 	buffer = (u32 *)obj->buffer.pointer;
 
 	if (buffer[0] != 0x4C4C4544 && buffer[1] != 0x494D5720)
-		pr_warn("Dell descriptor buffer has invalid signature (%*ph)\n",
+		dev_warn(&wdev->dev, "Dell descriptor buffer has invalid signature (%*ph)\n",
 			8, buffer);
 
 	if (buffer[2] != 0 && buffer[2] != 1)
-		pr_warn("Dell descriptor buffer has unknown version (%d)\n",
+		dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%d)\n",
 			buffer[2]);
 
 	if (buffer[3] != 4096)
-		pr_warn("Dell descriptor buffer has invalid buffer length (%d)\n",
+		dev_warn(&wdev->dev, "Dell descriptor buffer has invalid buffer length (%d)\n",
 			buffer[3]);
 
-	dell_wmi_interface_version = buffer[2];
+	priv->interface_version = buffer[2];
+	ret = 0;
 
-	pr_info("Detected Dell WMI interface version %u\n",
-		dell_wmi_interface_version);
+	dev_info(&wdev->dev, "Detected Dell WMI interface version %u\n",
+		priv->interface_version);
 
+out:
 	kfree(obj);
-	return 0;
+	put_device(&desc_dev->dev);
+	return ret;
 }
 
 /*
@@ -717,17 +724,19 @@ static int dell_wmi_events_set_enabled(bool enable)
 
 static int dell_wmi_probe(struct wmi_device *wdev)
 {
+	struct dell_wmi_priv *priv;
 	int err;
 
-	struct dell_wmi_priv *priv = devm_kzalloc(
+	priv = devm_kzalloc(
 		&wdev->dev, sizeof(struct dell_wmi_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+	dev_set_drvdata(&wdev->dev, priv);
 
-	err = dell_wmi_check_descriptor_buffer();
+	err = dell_wmi_check_descriptor_buffer(wdev);
 	if (err)
 		return err;
 
-	dev_set_drvdata(&wdev->dev, priv);
-
 	return dell_wmi_input_setup(wdev);
 }