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author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-11-04 09:09:37 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-11-04 09:09:37 -0700 |
commit | abfecb39092029c42c79bacac3d1c96a133ff231 (patch) | |
tree | cea82a61f7b2f850071311dab0695f49dddca166 /Documentation/driver-api | |
parent | 95faf6ba654dd334617f347023e65b06d791c4a6 (diff) | |
parent | cc8d7b4aea79df7cb45b74f9bc5b8a8bd2ed4c07 (diff) | |
download | linux-stable-abfecb39092029c42c79bacac3d1c96a133ff231.tar.gz linux-stable-abfecb39092029c42c79bacac3d1c96a133ff231.tar.bz2 linux-stable-abfecb39092029c42c79bacac3d1c96a133ff231.zip |
Merge tag 'tty-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty / serial driver updates from Greg KH:
"Here is the big set of tty and serial driver updates for 5.16-rc1.
Nothing major in here at all, just lots of tiny serial and tty driver
updates for various reported things, and some good cleanups. These
include:
- more good tty api cleanups from Jiri
- stm32 serial driver updates
- softlockup fix for non-preempt systems under high serial load
- rpmsg serial driver update
- 8250 drivers updates and fixes
- n_gsm line discipline fixes and updates as people are finally
starting to use it.
All of these have been in linux-next for a while now with no reported
issues"
* tag 'tty-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (86 commits)
tty: Fix extra "not" in TTY_DRIVER_REAL_RAW description
serial: cpm_uart: Protect udbg definitions by CONFIG_SERIAL_CPM_CONSOLE
tty: rpmsg: Define tty name via constant string literal
tty: rpmsg: Add pr_fmt() to prefix messages
tty: rpmsg: Use dev_err_probe() in ->probe()
tty: rpmsg: Unify variable used to keep an error code
tty: rpmsg: Assign returned id to a local variable
serial: stm32: push DMA RX data before suspending
serial: stm32: terminate / restart DMA transfer at suspend / resume
serial: stm32: rework RX dma initialization and release
serial: 8250_pci: Remove empty stub pci_quatech_exit()
serial: 8250_pci: Replace custom pci_match_id() implementation
serial: xilinx_uartps: Fix race condition causing stuck TX
serial: sunzilog: Mark sunzilog_putchar() __maybe_unused
Revert "tty: hvc: pass DMA capable memory to put_chars()"
Revert "virtio-console: remove unnecessary kmemdup()"
serial: 8250_pci: Replace dev_*() by pci_*() macros
serial: 8250_pci: Get rid of redundant 'else' keyword
serial: 8250_pci: Refactor the loop in pci_ite887x_init()
tty: add rpmsg driver
...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r-- | Documentation/driver-api/serial/n_gsm.rst | 71 | ||||
-rw-r--r-- | Documentation/driver-api/serial/tty.rst | 2 |
2 files changed, 63 insertions, 10 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 diff --git a/Documentation/driver-api/serial/tty.rst b/Documentation/driver-api/serial/tty.rst index dd972caacf3e..4b709f392713 100644 --- a/Documentation/driver-api/serial/tty.rst +++ b/Documentation/driver-api/serial/tty.rst @@ -58,7 +58,7 @@ close() This is called on a terminal when the line hangup() Called when the tty line is hung up. The line discipline should cease I/O to the tty. No further calls into the ldisc code will occur. - The return value is ignored. Can sleep. + Can sleep. read() (optional) A process requests reading data from the line. Multiple read calls may occur in parallel |