diff options
| author | Martin Hundebøll <martin@geanix.com> | 2019-08-12 23:12:43 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-04 12:43:54 +0200 |
| commit | a7b121b4b8b0bcc14fc1c2a81d34096109a65dd6 (patch) | |
| tree | 19c00636e4d396d430f254ad841f4226134b6f30 /Documentation/driver-api | |
| parent | d193db7fb10d3ae8322e5f65e4c39946156e24c2 (diff) | |
tty: n_gsm: add ioctl to map serial device to mux'ed tty
Guessing the first tty for a gsm0710 multiplexed serial device is not
currently possible, which makes it racy to use with multiple modems.
Add a way to map the physical serial tty to its related mux devices
using an ioctl.
Signed-off-by: Martin Hundebøll <martin@geanix.com>
Link: https://lore.kernel.org/r/20190812211243.98686-1-martin@geanix.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/driver-api')
| -rw-r--r-- | Documentation/driver-api/serial/n_gsm.rst | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/Documentation/driver-api/serial/n_gsm.rst b/Documentation/driver-api/serial/n_gsm.rst index 0ba731ab00b2..286e7ff4d2d9 100644 --- a/Documentation/driver-api/serial/n_gsm.rst +++ b/Documentation/driver-api/serial/n_gsm.rst @@ -18,10 +18,13 @@ How to use it 2. switch the serial line to using the n_gsm line discipline by using TIOCSETD ioctl, 3. configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl, +4. obtain base gsmtty number for the used serial port, Major parts of the initialization program : (a good starting point is util-linux-ng/sys-utils/ldattach.c):: + #include <stdio.h> + #include <stdint.h> #include <linux/gsmmux.h> #include <linux/tty.h> #define DEFAULT_SPEED B115200 @@ -30,6 +33,7 @@ Major parts of the initialization program : int ldisc = N_GSM0710; struct gsm_config c; struct termios configuration; + uint32_t first; /* open the serial port connected to the modem */ fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY); @@ -58,19 +62,22 @@ Major parts of the initialization program : c.mtu = 127; /* set the new configuration */ ioctl(fd, GSMIOC_SETCONF, &c); + /* get first gsmtty device node */ + ioctl(fd, GSMIOC_GETFIRST, &first); + printf("first muxed line: /dev/gsmtty%i\n", first); /* and wait for ever to keep the line discipline enabled */ daemon(0,0); pause(); -4. use these devices as plain serial ports. +5. use these devices as plain serial ports. for example, it's possible: - and to use gnokii to send / receive SMS on ttygsm1 - to use ppp to establish a datalink on ttygsm2 -5. first close all virtual ports before closing the physical port. +6. first close all virtual ports before closing the physical port. Note that after closing the physical port the modem is still in multiplexing mode. This may prevent a successful re-opening of the port later. To avoid |