Merge tag 'tty-5.17-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/serial driver updates for 5.17-rc1.

  Nothing major in here, just lots of good updates and fixes, including:

   - more tty core cleanups from Jiri as well as mxser driver cleanups.
     This is the majority of the core diffstat

   - tty documentation updates from Jiri

   - platform_get_irq() updates

   - various serial driver updates for new features and hardware

   - fifo usage for 8250 console, reducing cpu load a lot

   - LED fix for keyboards, long-time bugfix that went through many
     revisions

   - minor cleanups

  All have been in linux-next for a while with no reported problems"

* tag 'tty-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (119 commits)
  serial: core: Keep mctrl register state and cached copy in sync
  serial: stm32: correct loop for dma error handling
  serial: stm32: fix flow control transfer in DMA mode
  serial: stm32: rework TX DMA state condition
  serial: stm32: move tx dma terminate DMA to shutdown
  serial: pl011: Drop redundant DTR/RTS preservation on close/open
  serial: pl011: Drop CR register reset on set_termios
  serial: pl010: Drop CR register reset on set_termios
  serial: liteuart: fix MODULE_ALIAS
  serial: 8250_bcm7271: Fix return error code in case of dma_alloc_coherent() failure
  Revert "serdev: BREAK/FRAME/PARITY/OVERRUN notification prototype V2"
  tty: goldfish: Use platform_get_irq() to get the interrupt
  serdev: BREAK/FRAME/PARITY/OVERRUN notification prototype V2
  tty: serial: meson: Drop the legacy compatible strings and clock code
  serial: pmac_zilog: Use platform_get_irq() to get the interrupt
  serial: bcm63xx: Use platform_get_irq() to get the interrupt
  serial: ar933x: Use platform_get_irq() to get the interrupt
  serial: vt8500: Use platform_get_irq() to get the interrupt
  serial: altera_jtaguart: Use platform_get_irq_optional() to get the interrupt
  serial: pxa: Use platform_get_irq() to get the interrupt
  ...

3 files changed, 7 insertions, 330 deletions

diff --git a/Documentation/driver-api/serial/index.rst b/Documentation/driver-api/serial/index.rst
index 8f7d7af3b90b..7eb21a695fc3 100644
--- a/Documentation/driver-api/serial/index.rst
+++ b/Documentation/driver-api/serial/index.rst
@@ -9,7 +9,6 @@ Support for Serial devices
 
 
     driver
-    tty
 
 Serial drivers
 ==============
diff --git a/Documentation/driver-api/serial/n_gsm.rst b/Documentation/driver-api/serial/n_gsm.rst
index 8fe723ab9c67..49956509ad73 100644
--- a/Documentation/driver-api/serial/n_gsm.rst
+++ b/Documentation/driver-api/serial/n_gsm.rst
@@ -18,9 +18,12 @@ How to use it
 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 :
@@ -95,10 +98,13 @@ Major parts of the initialization program :
 
 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,
+
+2.4 obtain base gsmtty number for the used serial port::
 
   #include <stdio.h>
   #include <stdint.h>
diff --git a/Documentation/driver-api/serial/tty.rst b/Documentation/driver-api/serial/tty.rst
deleted file mode 100644
index 4b709f392713..000000000000
--- a/Documentation/driver-api/serial/tty.rst
+++ /dev/null
@@ -1,328 +0,0 @@
-=================
-The Lockronomicon
-=================
-
-Your guide to the ancient and twisted locking policies of the tty layer and
-the warped logic behind them. Beware all ye who read on.
-
-
-Line Discipline
----------------
-
-Line disciplines are registered with tty_register_ldisc() passing the
-discipline number and the ldisc structure. At the point of registration the
-discipline must be ready to use and it is possible it will get used before
-the call returns success. If the call returns an error then it won't get
-called. Do not re-use ldisc numbers as they are part of the userspace ABI
-and writing over an existing ldisc will cause demons to eat your computer.
-After the return the ldisc data has been copied so you may free your own
-copy of the structure. You must not re-register over the top of the line
-discipline even with the same data or your computer again will be eaten by
-demons.
-
-In order to remove a line discipline call tty_unregister_ldisc().
-In ancient times this always worked. In modern times the function will
-return -EBUSY if the ldisc is currently in use. Since the ldisc referencing
-code manages the module counts this should not usually be a concern.
-
-Heed this warning: the reference count field of the registered copies of the
-tty_ldisc structure in the ldisc table counts the number of lines using this
-discipline. The reference count of the tty_ldisc structure within a tty
-counts the number of active users of the ldisc at this instant. In effect it
-counts the number of threads of execution within an ldisc method (plus those
-about to enter and exit although this detail matters not).
-
-Line Discipline Methods
------------------------
-
-TTY side interfaces
-^^^^^^^^^^^^^^^^^^^
-
-======================= =======================================================
-open()			Called when the line discipline is attached to
-			the terminal. No other call into the line
-			discipline for this tty will occur until it
-			completes successfully. Should initialize any
-			state needed by the ldisc, and set receive_room
-			in the tty_struct to the maximum amount of data
-			the line discipline is willing to accept from the
-			driver with a single call to receive_buf().
-			Returning an error will prevent the ldisc from
-			being attached. Can sleep.
-
-close()			This is called on a terminal when the line
-			discipline is being unplugged. At the point of
-			execution no further users will enter the
-			ldisc code for this tty. Can sleep.
-
-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.
-			Can sleep.
-
-read()			(optional) A process requests reading data from
-			the line. Multiple read calls may occur in parallel
-			and the ldisc must deal with serialization issues.
-			If not defined, the process will receive an EIO
-			error. May sleep.
-
-write()			(optional) A process requests writing data to the
-			line. Multiple write calls are serialized by the
-			tty layer for the ldisc. If not defined, the
-			process will receive an EIO error. May sleep.
-
-flush_buffer()		(optional) May be called at any point between
-			open and close, and instructs the line discipline
-			to empty its input buffer.
-
-set_termios()		(optional) Called on termios structure changes.
-			The caller passes the old termios data and the
-			current data is in the tty. Called under the
-			termios semaphore so allowed to sleep. Serialized
-			against itself only.
-
-poll()			(optional) Check the status for the poll/select
-			calls. Multiple poll calls may occur in parallel.
-			May sleep.
-
-ioctl()			(optional) Called when an ioctl is handed to the
-			tty layer that might be for the ldisc. Multiple
-			ioctl calls may occur in parallel. May sleep.
-
-compat_ioctl()		(optional) Called when a 32 bit ioctl is handed
-			to the tty layer that might be for the ldisc.
-			Multiple ioctl calls may occur in parallel.
-			May sleep.
-======================= =======================================================
-
-Driver Side Interfaces
-^^^^^^^^^^^^^^^^^^^^^^
-
-======================= =======================================================
-receive_buf()		(optional) Called by the low-level driver to hand
-			a buffer of received bytes to the ldisc for
-			processing. The number of bytes is guaranteed not
-			to exceed the current value of tty->receive_room.
-			All bytes must be processed.
-
-receive_buf2()		(optional) Called by the low-level driver to hand
-			a buffer of received bytes to the ldisc for
-			processing. Returns the number of bytes processed.
-
-			If both receive_buf() and receive_buf2() are
-			defined, receive_buf2() should be preferred.
-
-write_wakeup()		May be called at any point between open and close.
-			The TTY_DO_WRITE_WAKEUP flag indicates if a call
-			is needed but always races versus calls. Thus the
-			ldisc must be careful about setting order and to
-			handle unexpected calls. Must not sleep.
-
-			The driver is forbidden from calling this directly
-			from the ->write call from the ldisc as the ldisc
-			is permitted to call the driver write method from
-			this function. In such a situation defer it.
-
-dcd_change()		Report to the tty line the current DCD pin status
-			changes and the relative timestamp. The timestamp
-			cannot be NULL.
-======================= =======================================================
-
-
-Driver Access
-^^^^^^^^^^^^^
-
-Line discipline methods can call the following methods of the underlying
-hardware driver through the function pointers within the tty->driver
-structure:
-
-======================= =======================================================
-write()			Write a block of characters to the tty device.
-			Returns the number of characters accepted. The
-			character buffer passed to this method is already
-			in kernel space.
-
-put_char()		Queues a character for writing to the tty device.
-			If there is no room in the queue, the character is
-			ignored.
-
-flush_chars()		(Optional) If defined, must be called after
-			queueing characters with put_char() in order to
-			start transmission.
-
-write_room()		Returns the numbers of characters the tty driver
-			will accept for queueing to be written.
-
-ioctl()			Invoke device specific ioctl.
-			Expects data pointers to refer to userspace.
-			Returns ENOIOCTLCMD for unrecognized ioctl numbers.
-
-set_termios()		Notify the tty driver that the device's termios
-			settings have changed. New settings are in
-			tty->termios. Previous settings should be passed in
-			the "old" argument.
-
-			The API is defined such that the driver should return
-			the actual modes selected. This means that the
-			driver function is responsible for modifying any
-			bits in the request it cannot fulfill to indicate
-			the actual modes being used. A device with no
-			hardware capability for change (e.g. a USB dongle or
-			virtual port) can provide NULL for this method.
-
-throttle()		Notify the tty driver that input buffers for the
-			line discipline are close to full, and it should
-			somehow signal that no more characters should be
-			sent to the tty.
-
-unthrottle()		Notify the tty driver that characters can now be
-			sent to the tty without fear of overrunning the
-			input buffers of the line disciplines.
-
-stop()			Ask the tty driver to stop outputting characters
-			to the tty device.
-
-start()			Ask the tty driver to resume sending characters
-			to the tty device.
-
-hangup()		Ask the tty driver to hang up the tty device.
-
-break_ctl()		(Optional) Ask the tty driver to turn on or off
-			BREAK status on the RS-232 port.  If state is -1,
-			then the BREAK status should be turned on; if
-			state is 0, then BREAK should be turned off.
-			If this routine is not implemented, use ioctls
-			TIOCSBRK / TIOCCBRK instead.
-
-wait_until_sent()	Waits until the device has written out all of the
-			characters in its transmitter FIFO.
-
-send_xchar()		Send a high-priority XON/XOFF character to the device.
-======================= =======================================================
-
-
-Flags
-^^^^^
-
-Line discipline methods have access to tty->flags field containing the
-following interesting flags:
-
-======================= =======================================================
-TTY_THROTTLED		Driver input is throttled. The ldisc should call
-			tty->driver->unthrottle() in order to resume
-			reception when it is ready to process more data.
-
-TTY_DO_WRITE_WAKEUP	If set, causes the driver to call the ldisc's
-			write_wakeup() method in order to resume
-			transmission when it can accept more data
-			to transmit.
-
-TTY_IO_ERROR		If set, causes all subsequent userspace read/write
-			calls on the tty to fail, returning -EIO.
-
-TTY_OTHER_CLOSED	Device is a pty and the other side has closed.
-
-TTY_NO_WRITE_SPLIT	Prevent driver from splitting up writes into
-			smaller chunks.
-======================= =======================================================
-
-
-Locking
-^^^^^^^
-
-Callers to the line discipline functions from the tty layer are required to
-take line discipline locks. The same is true of calls from the driver side
-but not yet enforced.
-
-Three calls are now provided::
-
-	ldisc = tty_ldisc_ref(tty);
-
-takes a handle to the line discipline in the tty and returns it. If no ldisc
-is currently attached or the ldisc is being closed and re-opened at this
-point then NULL is returned. While this handle is held the ldisc will not
-change or go away::
-
-	tty_ldisc_deref(ldisc)
-
-Returns the ldisc reference and allows the ldisc to be closed. Returning the
-reference takes away your right to call the ldisc functions until you take
-a new reference::
-
-	ldisc = tty_ldisc_ref_wait(tty);
-
-Performs the same function as tty_ldisc_ref except that it will wait for an
-ldisc change to complete and then return a reference to the new ldisc.
-
-While these functions are slightly slower than the old code they should have
-minimal impact as most receive logic uses the flip buffers and they only
-need to take a reference when they push bits up through the driver.
-
-A caution: The ldisc->open(), ldisc->close() and driver->set_ldisc
-functions are called with the ldisc unavailable. Thus tty_ldisc_ref will
-fail in this situation if used within these functions. Ldisc and driver
-code calling its own functions must be careful in this case.
-
-
-Driver Interface
-----------------
-
-======================= =======================================================
-open()			Called when a device is opened. May sleep
-
-close()			Called when a device is closed. At the point of
-			return from this call the driver must make no
-			further ldisc calls of any kind. May sleep
-
-write()			Called to write bytes to the device. May not
-			sleep. May occur in parallel in special cases.
-			Because this includes panic paths drivers generally
-			shouldn't try and do clever locking here.
-
-put_char()		Stuff a single character onto the queue. The
-			driver is guaranteed following up calls to
-			flush_chars.
-
-flush_chars()		Ask the kernel to write put_char queue
-
-write_room()		Return the number of characters that can be stuffed
-			into the port buffers without overflow (or less).
-			The ldisc is responsible for being intelligent
-			about multi-threading of write_room/write calls
-
-ioctl()			Called when an ioctl may be for the driver
-
-set_termios()		Called on termios change, serialized against
-			itself by a semaphore. May sleep.
-
-set_ldisc()		Notifier for discipline change. At the point this
-			is done the discipline is not yet usable. Can now
-			sleep (I think)
-
-throttle()		Called by the ldisc to ask the driver to do flow
-			control.  Serialization including with unthrottle
-			is the job of the ldisc layer.
-
-unthrottle()		Called by the ldisc to ask the driver to stop flow
-			control.
-
-stop()			Ldisc notifier to the driver to stop output. As with
-			throttle the serializations with start() are down
-			to the ldisc layer.
-
-start()			Ldisc notifier to the driver to start output.
-
-hangup()		Ask the tty driver to cause a hangup initiated
-			from the host side. [Can sleep ??]
-
-break_ctl()		Send RS232 break. Can sleep. Can get called in
-			parallel, driver must serialize (for now), and
-			with write calls.
-
-wait_until_sent()	Wait for characters to exit the hardware queue
-			of the driver. Can sleep
-
-send_xchar()	  	Send XON/XOFF and if possible jump the queue with
-			it in order to get fast flow control responses.
-			Cannot sleep ??
-======================= =======================================================