[PATCH] staging: pi433: add descriptions for mutex locks

[Valentin Vidic]

Removes TODO for tx_fifo_lock as tx_fifo is modified from
both pi433_tx_thread and pi433_write.

Fixes checkpatch warning:

  CHECK: struct mutex definition without comment

Signed-off-by: Valentin Vidic <Valentin.Vidic@xxxxxxxxx>
---
 drivers/staging/pi433/pi433_if.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
index d1e0ddbc79ce..f6f106a3ff8e 100644
--- a/drivers/staging/pi433/pi433_if.c
+++ b/drivers/staging/pi433/pi433_if.c
@@ -87,7 +87,7 @@ struct pi433_device {
 
 	/* tx related values */
 	STRUCT_KFIFO_REC_1(MSG_FIFO_SIZE) tx_fifo;
-	struct mutex		tx_fifo_lock; // TODO: check, whether necessary or obsolete
+	struct mutex		tx_fifo_lock; /* serialize access to tx_fifo */
 	struct task_struct	*tx_task_struct;
 	wait_queue_head_t	tx_wait_queue;
 	u8			free_in_fifo;
@@ -100,7 +100,7 @@ struct pi433_device {
 	u32			rx_bytes_to_drop;
 	u32			rx_bytes_dropped;
 	unsigned int		rx_position;
-	struct mutex		rx_lock;
+	struct mutex		rx_lock; /* serialize read requests */
 	wait_queue_head_t	rx_wait_queue;
 
 	/* fifo wait queue */
-- 
2.16.2