From: Daniel Starke <daniel.starke@xxxxxxxxxxx> n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010. See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516 The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.2.1.2 describes the encoding of the address field within the frame header. It is made up of the DLCI address, command/response (CR) bit and EA bit. Use the predefined CR value instead of a plain 2 in alignment to the remaining code and to make the encoding obvious. Signed-off-by: Daniel Starke <daniel.starke@xxxxxxxxxxx> --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 9bf5aa508f0e..1beb4b28cd18 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -751,7 +751,7 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) *--dp = msg->ctrl; if (gsm->initiator) - *--dp = (msg->addr << 2) | 2 | EA; + *--dp = (msg->addr << 2) | CR | EA; else *--dp = (msg->addr << 2) | EA; *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); -- 2.25.1