Merge branch 'i2c-hid' into for-linus

- ensure various commands do not interfere with each other (Dmitry
  Torokhov)

Author: Benjamin Tissoires

drivers/hid/i2c-hid/i2c-hid-core.c

@@ -105,6 +105,7 @@ struct i2c_hid {
 
 	wait_queue_head_t	wait;		/* For waiting the interrupt */
 
+	struct mutex		cmd_lock;	/* protects cmdbuf and rawbuf */
 	struct mutex		reset_lock;
 
 	struct i2chid_ops	*ops;
@@ -220,6 +221,8 @@ static int i2c_hid_xfer(struct i2c_hid *ihid,
 static int i2c_hid_read_register(struct i2c_hid *ihid, __le16 reg,
 				 void *buf, size_t len)
 {
+	guard(mutex)(&ihid->cmd_lock);
+
 	*(__le16 *)ihid->cmdbuf = reg;
 
 	return i2c_hid_xfer(ihid, ihid->cmdbuf, sizeof(__le16), buf, len);
@@ -252,6 +255,8 @@ static int i2c_hid_get_report(struct i2c_hid *ihid,
 
 	i2c_hid_dbg(ihid, "%s\n", __func__);
 
+	guard(mutex)(&ihid->cmd_lock);
+
 	/* Command register goes first */
 	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
 	length += sizeof(__le16);
@@ -342,6 +347,8 @@ static int i2c_hid_set_or_send_report(struct i2c_hid *ihid,
 	if (!do_set && le16_to_cpu(ihid->hdesc.wMaxOutputLength) == 0)
 		return -ENOSYS;
 
+	guard(mutex)(&ihid->cmd_lock);
+
 	if (do_set) {
 		/* Command register goes first */
 		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
@@ -384,6 +391,8 @@ static int i2c_hid_set_power_command(struct i2c_hid *ihid, int power_state)
 {
 	size_t length;
 
+	guard(mutex)(&ihid->cmd_lock);
+
 	/* SET_POWER uses command register */
 	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
 	length = sizeof(__le16);
@@ -440,25 +449,27 @@ static int i2c_hid_start_hwreset(struct i2c_hid *ihid)
 	if (ret)
 		return ret;
 
-	/* Prepare reset command. Command register goes first. */
-	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
-	length += sizeof(__le16);
-	/* Next is RESET command itself */
-	length += i2c_hid_encode_command(ihid->cmdbuf + length,
-					 I2C_HID_OPCODE_RESET, 0, 0);
+	scoped_guard(mutex, &ihid->cmd_lock) {
+		/* Prepare reset command. Command register goes first. */
+		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
+		length += sizeof(__le16);
+		/* Next is RESET command itself */
+		length += i2c_hid_encode_command(ihid->cmdbuf + length,
+						 I2C_HID_OPCODE_RESET, 0, 0);
 
-	set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
+		set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
 
-	ret = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
-	if (ret) {
-		dev_err(&ihid->client->dev,
-			"failed to reset device: %d\n", ret);
-		goto err_clear_reset;
-	}
+		ret = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
+		if (ret) {
+			dev_err(&ihid->client->dev,
+				"failed to reset device: %d\n", ret);
+			break;
+		}
 
-	return 0;
+		return 0;
+	}
 
-err_clear_reset:
+	/* Clean up if sending reset command failed */
 	clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
 	i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
 	return ret;
@@ -1200,6 +1211,7 @@ int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
 	ihid->is_panel_follower = drm_is_panel_follower(&client->dev);
 
 	init_waitqueue_head(&ihid->wait);
+	mutex_init(&ihid->cmd_lock);
 	mutex_init(&ihid->reset_lock);
 	INIT_WORK(&ihid->panel_follower_prepare_work, ihid_core_panel_prepare_work);