diff options
Diffstat (limited to 'Documentation/driver-api')
| -rw-r--r-- | Documentation/driver-api/serial/n_gsm.rst | 71 |
1 files changed, 62 insertions, 9 deletions
diff --git a/Documentation/driver-api/serial/n_gsm.rst b/Documentation/driver-api/serial/n_gsm.rst index 87dfcd54a96b..8fe723ab9c67 100644 --- a/Documentation/driver-api/serial/n_gsm.rst +++ b/Documentation/driver-api/serial/n_gsm.rst @@ -12,13 +12,16 @@ modems connected to a physical serial port. How to use it ------------- -1. initialize the modem in 0710 mux mode (usually AT+CMUX= command) through - its serial port. Depending on the modem used, you can pass more or less - parameters to this command, -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, +1. config initiator +^^^^^^^^^^^^^^^^^^^^^ + +1.1 initialize the modem in 0710 mux mode (usually AT+CMUX= command) through + its serial port. Depending on the modem used, you can pass more or less + parameters to this command. +1.2 switch the serial line to using the n_gsm line discipline by using + TIOCSETD ioctl. +1.3 configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl. +1.4 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):: @@ -70,14 +73,14 @@ Major parts of the initialization program : daemon(0,0); pause(); -5. use these devices as plain serial ports. +1.5 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 -6. first close all virtual ports before closing the physical port. +1.6 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 @@ -87,6 +90,56 @@ Major parts of the initialization program : 0xf9, 0x03, 0xef, 0x03, 0xc3, 0x16, 0xf9. +2. config requester +^^^^^^^^^^^^^^^^^^^^^ + +2.1 receive string "AT+CMUX= command" through its serial port,initialize + mux mode config +2.2 switch the serial line to using the n_gsm line discipline by using + TIOCSETD ioctl. +2.3 configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl. +2.4 obtain base gsmtty number for the used serial port, + + #include <stdio.h> + #include <stdint.h> + #include <linux/gsmmux.h> + #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 */ + fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY); + + /* configure the serial port : speed, flow control ... */ + + /* get serial data and check "AT+CMUX=command" parameter ... */ + + /* use n_gsm line discipline */ + ioctl(fd, TIOCSETD, &ldisc); + + /* get n_gsm configuration */ + ioctl(fd, GSMIOC_GETCONF, &c); + /* we are requester and need encoding 0 (basic) */ + c.initiator = 0; + c.encapsulation = 0; + /* our modem defaults to a maximum size of 127 bytes */ + c.mru = 127; + 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(); + Additional Documentation ------------------------ More practical details on the protocol and how it's supported by industrial |