lkml.org 
[lkml]   [2023]   [Feb]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 2/3] tty: n_gsm: add RING/CD control support
Date
From: Daniel Starke <daniel.starke@siemens.com>

The status lines ring and carrier detect are used by the modem to signal
incoming calls (RING) or an established connection (CD). This is
implemented as physical lines on a standard RS232 connection. However,
the muxer protocol encodes these status lines as modem bits IC and DV.
These incoming lines are masked by tty driver (see tty_io.c) and cannot be
set by a user application.

Allow setting RING via TIOCM_OUT1 and CD via TIOCM_OUT2 to allow
implementation of a modem or modem emulator.

Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
---
drivers/tty/n_gsm.c | 5 +++++
1 file changed, 5 insertions(+)

v1 -> v2:
No changes.

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index d068df1cf2fd..cf1ab7d619d9 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -546,6 +546,11 @@ static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
modembits |= MDM_IC;
if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
modembits |= MDM_DV;
+ /* special mappings for passive side to operate as UE */
+ if (dlci->modem_tx & TIOCM_OUT1)
+ modembits |= MDM_IC;
+ if (dlci->modem_tx & TIOCM_OUT2)
+ modembits |= MDM_DV;
return modembits;
}

--
2.34.1
\
 
 \ /
  Last update: 2023-03-27 00:07    [W:0.147 / U:0.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site