staging: pi433: add docs to packet_format and tx_start_condition enum

While pi433 driver deals with the nuances of the different possible
config combinations, it's hard (at first) to understand the rationale
for some of the tx/rx-related source code unless you're fairly familiar
with the rf69's inner workings.

This patch documents the expected behaviour and limits of both
packet_format and tx_start_condition enum fields.

Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Link: https://lore.kernel.org/r/20211231001933.GA6779@mail.google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/pi433/rf69_enum.h b/drivers/staging/pi433/rf69_enum.h
index fbf56fc..b33a33a 100644 (file)
--- a/drivers/staging/pi433/rf69_enum.h
+++ b/drivers/staging/pi433/rf69_enum.h
@@ -110,12 +110,24 @@ enum fifo_fill_condition {
 };
 
 enum packet_format {
+       /*
+        * Used when the size of payload is fixed in advance. This mode of
+        * operation may be of interest to minimize RF overhead by 1 byte as
+        * no length byte field is required
+        */
        packet_length_fix,
+       /*
+        * Used when the size of payload isn't known in advance. It requires the
+        * transmitter to send the length byte in each packet so the receiver
+        * would know how to operate properly
+        */
        packet_length_var
 };
 
 enum tx_start_condition {
+       /* the number of bytes in the FIFO exceeds FIFO_THRESHOLD */
        fifo_level,
+       /* at least one byte in the FIFO */
        fifo_not_empty
 };