Merge tag 'tty-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Even in this age, people are still making new serial port silicon,
  why...

  Anyway, here's the TTY and Serial driver update for 5.4-rc1. Lots of
  changes in here for a number of embedded serial port devices that are
  being worked on because people really like to see those console
  logs...

  Other than that, nothing major here, no core tty changes that anyone
  should care about.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (125 commits)
  serial: tegra: Add PIO mode support
  serial: tegra: report clk rate errors
  serial: tegra: add support to adjust baud rate
  serial: tegra: DT for Adjusted baud rates
  serial: tegra: add support to use 8 bytes trigger
  serial: tegra: set maximum num of uart ports to 8
  serial: tegra: check for FIFO mode enabled status
  dt-binding: serial: tegra: add new chips
  serial: tegra: report error to upper tty layer
  serial: tegra: flush the RX fifo on frame error
  serial: tegra: avoid reg access when clk disabled
  serial: tegra: add support to ignore read
  serial: sprd: correct the wrong sequence of arguments
  dt-bindings: serial: Convert riscv,sifive-serial to json-schema
  serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control
  serial: max310x: Properly set flags in AutoCTS mode
  tty: serial: fix platform_no_drv_owner.cocci warnings
  dt-bindings: serial: Document Freescale LINFlexD UART
  serial: fsl_linflexuart: Update compatible string
  tty: n_gsm: avoid recursive locking with async port hangup
  ...

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: