Documentation: tty: move n_gsm to tty

We have n_tty documented in Documentation/driver-api/tty/. n_gsm belongs
there too, so move from serial/ to tty/ too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220411110143.10019-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 0 insertions, 160 deletions

diff --git a/Documentation/driver-api/serial/index.rst b/Documentation/driver-api/serial/index.rst
index 7eb21a695fc3..4ebdb86cd6b6 100644
--- a/Documentation/driver-api/serial/index.rst
+++ b/Documentation/driver-api/serial/index.rst
@@ -17,7 +17,6 @@ Serial drivers
     :maxdepth: 1
 
     moxa-smartio
-    n_gsm
     serial-iso7816
     serial-rs485
 
diff --git a/Documentation/driver-api/serial/n_gsm.rst b/Documentation/driver-api/serial/n_gsm.rst
deleted file mode 100644
index 49956509ad73..000000000000
--- a/Documentation/driver-api/serial/n_gsm.rst
+++ /dev/null
@@ -1,159 +0,0 @@
-==============================
-GSM 0710 tty multiplexor HOWTO
-==============================
-
-This line discipline implements the GSM 07.10 multiplexing protocol
-detailed in the following 3GPP document:
-
-	https://www.3gpp.org/ftp/Specs/archive/07_series/07.10/0710-720.zip
-
-This document give some hints on how to use this driver with GPRS and 3G
-modems connected to a physical serial port.
-
-How to use it
--------------
-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)::
-
-  #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 connected to the modem */
-	fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY);
-
-	/* configure the serial port : speed, flow control ... */
-
-	/* send the AT commands to switch the modem to CMUX mode
-	   and check that it's successful (should return OK) */
-	write(fd, "AT+CMUX=0\r", 10);
-
-	/* experience showed that some modems need some time before
-	   being able to answer to the first MUX packet so a delay
-	   may be needed here in some case */
-	sleep(3);
-
-	/* use n_gsm line discipline */
-	ioctl(fd, TIOCSETD, &ldisc);
-
-	/* get n_gsm configuration */
-	ioctl(fd, GSMIOC_GETCONF, &c);
-	/* we are initiator and need encoding 0 (basic) */
-	c.initiator = 1;
-	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();
-
-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
-
-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
-   this situation either reset the modem if your hardware allows that or send
-   a disconnect command frame manually before initializing the multiplexing mode
-   for the second time. The byte sequence for the disconnect command frame is::
-
-      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
-modems can be found in the following documents :
-
-- http://www.telit.com/module/infopool/download.php?id=616
-- http://www.u-blox.com/images/downloads/Product_Docs/LEON-G100-G200-MuxImplementation_ApplicationNote_%28GSM%20G1-CS-10002%29.pdf
-- http://www.sierrawireless.com/Support/Downloads/AirPrime/WMP_Series/~/media/Support_Downloads/AirPrime/Application_notes/CMUX_Feature_Application_Note-Rev004.ashx
-- http://wm.sim.com/sim/News/photo/2010721161442.pdf
-
-11-03-08 - Eric Bénard - <eric@eukrea.com>