HID: playstation: track devices in list.

Track devices in a list, so we can detect when a device is connected
twice when using Bluetooth and USB.
Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com>
Reviewed-by: Barnabás Pőcze <pobrn@protonmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

drivers/hid/hid-playstation.c

@@ -15,10 +15,15 @@
 
 #include "hid-ids.h"
 
+/* List of connected playstation devices. */
+static DEFINE_MUTEX(ps_devices_lock);
+static LIST_HEAD(ps_devices_list);
+
 #define HID_PLAYSTATION_VERSION_PATCH 0x8000
 
 /* Base class for playstation devices. */
 struct ps_device {
+	struct list_head list;
 	struct hid_device *hdev;
 	spinlock_t lock;
 
@@ -160,6 +165,38 @@ static const struct {int x; int y; } ps_gamepad_hat_mapping[] = {
 	{0, 0},
 };
 
+/*
+ * Add a new ps_device to ps_devices if it doesn't exist.
+ * Return error on duplicate device, which can happen if the same
+ * device is connected using both Bluetooth and USB.
+ */
+static int ps_devices_list_add(struct ps_device *dev)
+{
+	struct ps_device *entry;
+
+	mutex_lock(&ps_devices_lock);
+	list_for_each_entry(entry, &ps_devices_list, list) {
+		if (!memcmp(entry->mac_address, dev->mac_address, sizeof(dev->mac_address))) {
+			hid_err(dev->hdev, "Duplicate device found for MAC address %pMR.\n",
+					dev->mac_address);
+			mutex_unlock(&ps_devices_lock);
+			return -EEXIST;
+		}
+	}
+
+	list_add_tail(&dev->list, &ps_devices_list);
+	mutex_unlock(&ps_devices_lock);
+	return 0;
+}
+
+static int ps_devices_list_remove(struct ps_device *dev)
+{
+	mutex_lock(&ps_devices_lock);
+	list_del(&dev->list);
+	mutex_unlock(&ps_devices_lock);
+	return 0;
+}
+
 static struct input_dev *ps_allocate_input_dev(struct hid_device *hdev, const char *name_suffix)
 {
 	struct input_dev *input_dev;
@@ -675,6 +712,10 @@ static struct ps_device *dualsense_create(struct hid_device *hdev)
 	}
 	snprintf(hdev->uniq, sizeof(hdev->uniq), "%pMR", ds->base.mac_address);
 
+	ret = ps_devices_list_add(ps_dev);
+	if (ret)
+		return ERR_PTR(ret);
+
 	ret = dualsense_get_calibration_data(ds);
 	if (ret) {
 		hid_err(hdev, "Failed to get calibration data from DualSense\n");
@@ -707,6 +748,7 @@ static struct ps_device *dualsense_create(struct hid_device *hdev)
 	return &ds->base;
 
 err:
+	ps_devices_list_remove(ps_dev);
 	return ERR_PTR(ret);
 }
 
@@ -764,6 +806,10 @@ static int ps_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 static void ps_remove(struct hid_device *hdev)
 {
+	struct ps_device *dev = hid_get_drvdata(hdev);
+
+	ps_devices_list_remove(dev);
+
 	hid_hw_close(hdev);
 	hid_hw_stop(hdev);
 }