ideapad-laptop: Blacklist rfkill control on the Lenovo Yoga 2 11

The Lenovo Yoga 2 11 always reports everything as blocked, causing userspace
to not even try to use the wlan / bluetooth even though they work fine.

Note this patch also removes the "else priv->rfk[i] = NULL;" bit of the
rfkill initialization, it is not necessary as the priv struct is allocated
with kzalloc.

Reported-and-tested-by: Vincent Gerris <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>
Signed-off-by: Matthew Garrett <[e-mail]>

drivers/platform/x86/ideapad-laptop.c

···
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/i8042.h>
+#include <linux/dmi.h>
 
 #define IDEAPAD_RFKILL_DEV_NUM	(3)
 
···
 	}
 }
 
+/* Blacklist for devices where the ideapad rfkill interface does not work */
+static struct dmi_system_id rfkill_blacklist[] = {
+	/* The Lenovo Yoga 2 11 always reports everything as blocked */
+	{
+		.ident = "Lenovo Yoga 2 11",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo Yoga 2 11"),
+		},
+	},
+	{}
+};
+
 static int ideapad_acpi_add(struct platform_device *pdev)
 {
 	int ret, i;
···
 	if (ret)
 		goto input_failed;
 
-	for (i = 0; i < IDEAPAD_RFKILL_DEV_NUM; i++) {
-		if (test_bit(ideapad_rfk_data[i].cfgbit, &priv->cfg))
-			ideapad_register_rfkill(priv, i);
-		else
-			priv->rfk[i] = NULL;
+	if (!dmi_check_system(rfkill_blacklist)) {
+		for (i = 0; i < IDEAPAD_RFKILL_DEV_NUM; i++)
+			if (test_bit(ideapad_rfk_data[i].cfgbit, &priv->cfg))
+				ideapad_register_rfkill(priv, i);
 	}
 	ideapad_sync_rfk_state(priv);
 	ideapad_sync_touchpad_state(priv);