diff options
Diffstat (limited to 'Documentation/driver-api/serial/n_gsm.rst')
| -rw-r--r-- | Documentation/driver-api/serial/n_gsm.rst | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/Documentation/driver-api/serial/n_gsm.rst b/Documentation/driver-api/serial/n_gsm.rst index f3ad9fd26408..286e7ff4d2d9 100644 --- a/Documentation/driver-api/serial/n_gsm.rst +++ b/Documentation/driver-api/serial/n_gsm.rst @@ -18,18 +18,22 @@ 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> - #define N_GSM0710 21 /* GSM 0710 Mux */ + #include <linux/tty.h> #define DEFAULT_SPEED B115200 #define SERIAL_PORT /dev/ttyS0 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); @@ -58,21 +62,14 @@ 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. create the devices corresponding to the "virtual" serial ports (take care, - each modem has its configuration and some DLC have dedicated functions, - for example GPS), starting with minor 1 (DLC0 is reserved for the management - of the mux):: - - MAJOR=`cat /proc/devices |grep gsmtty | awk '{print $1}` - for i in `seq 1 4`; do - mknod /dev/ttygsm$i c $MAJOR $i - done - 5. use these devices as plain serial ports. for example, it's possible: |