Merge tag 'docs-5.3' of git://git.lwn.net/linux

Pull Documentation updates from Jonathan Corbet:
 "It's been a relatively busy cycle for docs:

   - A fair pile of RST conversions, many from Mauro. These create more
     than the usual number of simple but annoying merge conflicts with
     other trees, unfortunately. He has a lot more of these waiting on
     the wings that, I think, will go to you directly later on.

   - A new document on how to use merges and rebases in kernel repos,
     and one on Spectre vulnerabilities.

   - Various improvements to the build system, including automatic
     markup of function() references because some people, for reasons I
     will never understand, were of the opinion that
     :c:func:``function()`` is unattractive and not fun to type.

   - We now recommend using sphinx 1.7, but still support back to 1.4.

   - Lots of smaller improvements, warning fixes, typo fixes, etc"

* tag 'docs-5.3' of git://git.lwn.net/linux: (129 commits)
  docs: automarkup.py: ignore exceptions when seeking for xrefs
  docs: Move binderfs to admin-guide
  Disable Sphinx SmartyPants in HTML output
  doc: RCU callback locks need only _bh, not necessarily _irq
  docs: format kernel-parameters -- as code
  Doc : doc-guide : Fix a typo
  platform: x86: get rid of a non-existent document
  Add the RCU docs to the core-api manual
  Documentation: RCU: Add TOC tree hooks
  Documentation: RCU: Rename txt files to rst
  Documentation: RCU: Convert RCU UP systems to reST
  Documentation: RCU: Convert RCU linked list to reST
  Documentation: RCU: Convert RCU basic concepts to reST
  docs: filesystems: Remove uneeded .rst extension on toctables
  scripts/sphinx-pre-install: fix out-of-tree build
  docs: zh_CN: submitting-drivers.rst: Remove a duplicated Documentation/
  Documentation: PGP: update for newer HW devices
  Documentation: Add section about CPU vulnerabilities for Spectre
  Documentation: platform: Delete x86-laptop-drivers.txt
  docs: Note that :c:func: should no longer be used
  ...

9 files changed, 346 insertions, 12 deletions

diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst
index e970fadf4d1a..1ba88c7b3984 100644
--- a/Documentation/driver-api/basics.rst
+++ b/Documentation/driver-api/basics.rst
@@ -115,9 +115,6 @@ Kernel utility functions
 .. kernel-doc:: kernel/rcu/tree.c
    :export:
 
-.. kernel-doc:: kernel/rcu/tree_plugin.h
-   :export:
-
 .. kernel-doc:: kernel/rcu/update.c
    :export:
 
diff --git a/Documentation/driver-api/clk.rst b/Documentation/driver-api/clk.rst
index 593cca5058b1..3cad45d14187 100644
--- a/Documentation/driver-api/clk.rst
+++ b/Documentation/driver-api/clk.rst
@@ -175,9 +175,9 @@ the following::
 To take advantage of your data you'll need to support valid operations
 for your clk::
 
-	struct clk_ops clk_foo_ops {
-		.enable		= &clk_foo_enable;
-		.disable	= &clk_foo_disable;
+	struct clk_ops clk_foo_ops = {
+		.enable		= &clk_foo_enable,
+		.disable	= &clk_foo_disable,
 	};
 
 Implement the above functions using container_of::
diff --git a/Documentation/driver-api/firmware/other_interfaces.rst b/Documentation/driver-api/firmware/other_interfaces.rst
index a4ac54b5fd79..b81794e0cfbb 100644
--- a/Documentation/driver-api/firmware/other_interfaces.rst
+++ b/Documentation/driver-api/firmware/other_interfaces.rst
@@ -33,7 +33,7 @@ of the requests on to a secure monitor (EL3).
    :functions: stratix10_svc_client_msg
 
 .. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
-   :functions: stratix10_svc_command_reconfig_payload
+   :functions: stratix10_svc_command_config_type
 
 .. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
    :functions: stratix10_svc_cb_data
diff --git a/Documentation/driver-api/gpio/board.rst b/Documentation/driver-api/gpio/board.rst
index b37f3f7b8926..ce91518bf9f4 100644
--- a/Documentation/driver-api/gpio/board.rst
+++ b/Documentation/driver-api/gpio/board.rst
@@ -101,7 +101,7 @@ with the help of _DSD (Device Specific Data), introduced in ACPI 5.1::
 	}
 
 For more information about the ACPI GPIO bindings see
-Documentation/acpi/gpio-properties.txt.
+Documentation/firmware-guide/acpi/gpio-properties.rst.
 
 Platform Data
 -------------
diff --git a/Documentation/driver-api/gpio/consumer.rst b/Documentation/driver-api/gpio/consumer.rst
index 9559aa3cbcef..423492d125b9 100644
--- a/Documentation/driver-api/gpio/consumer.rst
+++ b/Documentation/driver-api/gpio/consumer.rst
@@ -435,7 +435,7 @@ case, it will be handled by the GPIO subsystem automatically.  However, if the
 _DSD is not present, the mappings between GpioIo()/GpioInt() resources and GPIO
 connection IDs need to be provided by device drivers.
 
-For details refer to Documentation/acpi/gpio-properties.txt
+For details refer to Documentation/firmware-guide/acpi/gpio-properties.rst
 
 
 Interacting With the Legacy GPIO Subsystem
diff --git a/Documentation/driver-api/iio/hw-consumer.rst b/Documentation/driver-api/iio/hw-consumer.rst
index e0fe0b98230e..819fb9edc005 100644
--- a/Documentation/driver-api/iio/hw-consumer.rst
+++ b/Documentation/driver-api/iio/hw-consumer.rst
@@ -45,7 +45,6 @@ A typical IIO HW consumer setup looks like this::
 
 More details
 ============
-.. kernel-doc:: include/linux/iio/hw-consumer.h
 .. kernel-doc:: drivers/iio/buffer/industrialio-hw-consumer.c
    :export:
 
diff --git a/Documentation/driver-api/pps.rst b/Documentation/driver-api/pps.rst
new file mode 100644
index 000000000000..1456d2c32ebd
--- /dev/null
+++ b/Documentation/driver-api/pps.rst
@@ -0,0 +1,242 @@
+:orphan:
+
+======================
+PPS - Pulse Per Second
+======================
+
+Copyright (C) 2007 Rodolfo Giometti <giometti@enneenne.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+
+
+Overview
+--------
+
+LinuxPPS provides a programming interface (API) to define in the
+system several PPS sources.
+
+PPS means "pulse per second" and a PPS source is just a device which
+provides a high precision signal each second so that an application
+can use it to adjust system clock time.
+
+A PPS source can be connected to a serial port (usually to the Data
+Carrier Detect pin) or to a parallel port (ACK-pin) or to a special
+CPU's GPIOs (this is the common case in embedded systems) but in each
+case when a new pulse arrives the system must apply to it a timestamp
+and record it for userland.
+
+Common use is the combination of the NTPD as userland program, with a
+GPS receiver as PPS source, to obtain a wallclock-time with
+sub-millisecond synchronisation to UTC.
+
+
+RFC considerations
+------------------
+
+While implementing a PPS API as RFC 2783 defines and using an embedded
+CPU GPIO-Pin as physical link to the signal, I encountered a deeper
+problem:
+
+   At startup it needs a file descriptor as argument for the function
+   time_pps_create().
+
+This implies that the source has a /dev/... entry. This assumption is
+OK for the serial and parallel port, where you can do something
+useful besides(!) the gathering of timestamps as it is the central
+task for a PPS API. But this assumption does not work for a single
+purpose GPIO line. In this case even basic file-related functionality
+(like read() and write()) makes no sense at all and should not be a
+precondition for the use of a PPS API.
+
+The problem can be simply solved if you consider that a PPS source is
+not always connected with a GPS data source.
+
+So your programs should check if the GPS data source (the serial port
+for instance) is a PPS source too, and if not they should provide the
+possibility to open another device as PPS source.
+
+In LinuxPPS the PPS sources are simply char devices usually mapped
+into files /dev/pps0, /dev/pps1, etc.
+
+
+PPS with USB to serial devices
+------------------------------
+
+It is possible to grab the PPS from an USB to serial device. However,
+you should take into account the latencies and jitter introduced by
+the USB stack. Users have reported clock instability around +-1ms when
+synchronized with PPS through USB. With USB 2.0, jitter may decrease
+down to the order of 125 microseconds.
+
+This may be suitable for time server synchronization with NTP because
+of its undersampling and algorithms.
+
+If your device doesn't report PPS, you can check that the feature is
+supported by its driver. Most of the time, you only need to add a call
+to usb_serial_handle_dcd_change after checking the DCD status (see
+ch341 and pl2303 examples).
+
+
+Coding example
+--------------
+
+To register a PPS source into the kernel you should define a struct
+pps_source_info as follows::
+
+    static struct pps_source_info pps_ktimer_info = {
+	    .name         = "ktimer",
+	    .path         = "",
+	    .mode         = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
+			    PPS_ECHOASSERT |
+			    PPS_CANWAIT | PPS_TSFMT_TSPEC,
+	    .echo         = pps_ktimer_echo,
+	    .owner        = THIS_MODULE,
+    };
+
+and then calling the function pps_register_source() in your
+initialization routine as follows::
+
+    source = pps_register_source(&pps_ktimer_info,
+			PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
+
+The pps_register_source() prototype is::
+
+  int pps_register_source(struct pps_source_info *info, int default_params)
+
+where "info" is a pointer to a structure that describes a particular
+PPS source, "default_params" tells the system what the initial default
+parameters for the device should be (it is obvious that these parameters
+must be a subset of ones defined in the struct
+pps_source_info which describe the capabilities of the driver).
+
+Once you have registered a new PPS source into the system you can
+signal an assert event (for example in the interrupt handler routine)
+just using::
+
+    pps_event(source, &ts, PPS_CAPTUREASSERT, ptr)
+
+where "ts" is the event's timestamp.
+
+The same function may also run the defined echo function
+(pps_ktimer_echo(), passing to it the "ptr" pointer) if the user
+asked for that... etc..
+
+Please see the file drivers/pps/clients/pps-ktimer.c for example code.
+
+
+SYSFS support
+-------------
+
+If the SYSFS filesystem is enabled in the kernel it provides a new class::
+
+   $ ls /sys/class/pps/
+   pps0/  pps1/  pps2/
+
+Every directory is the ID of a PPS sources defined in the system and
+inside you find several files::
+
+   $ ls -F /sys/class/pps/pps0/
+   assert     dev        mode       path       subsystem@
+   clear      echo       name       power/     uevent
+
+
+Inside each "assert" and "clear" file you can find the timestamp and a
+sequence number::
+
+   $ cat /sys/class/pps/pps0/assert
+   1170026870.983207967#8
+
+Where before the "#" is the timestamp in seconds; after it is the
+sequence number. Other files are:
+
+ * echo: reports if the PPS source has an echo function or not;
+
+ * mode: reports available PPS functioning modes;
+
+ * name: reports the PPS source's name;
+
+ * path: reports the PPS source's device path, that is the device the
+   PPS source is connected to (if it exists).
+
+
+Testing the PPS support
+-----------------------
+
+In order to test the PPS support even without specific hardware you can use
+the pps-ktimer driver (see the client subsection in the PPS configuration menu)
+and the userland tools available in your distribution's pps-tools package,
+http://linuxpps.org , or https://github.com/redlab-i/pps-tools.
+
+Once you have enabled the compilation of pps-ktimer just modprobe it (if
+not statically compiled)::
+
+   # modprobe pps-ktimer
+
+and the run ppstest as follow::
+
+   $ ./ppstest /dev/pps1
+   trying PPS source "/dev/pps1"
+   found PPS source "/dev/pps1"
+   ok, found 1 source(s), now start fetching data...
+   source 0 - assert 1186592699.388832443, sequence: 364 - clear  0.000000000, sequence: 0
+   source 0 - assert 1186592700.388931295, sequence: 365 - clear  0.000000000, sequence: 0
+   source 0 - assert 1186592701.389032765, sequence: 366 - clear  0.000000000, sequence: 0
+
+Please note that to compile userland programs, you need the file timepps.h.
+This is available in the pps-tools repository mentioned above.
+
+
+Generators
+----------
+
+Sometimes one needs to be able not only to catch PPS signals but to produce
+them also. For example, running a distributed simulation, which requires
+computers' clock to be synchronized very tightly. One way to do this is to
+invent some complicated hardware solutions but it may be neither necessary
+nor affordable. The cheap way is to load a PPS generator on one of the
+computers (master) and PPS clients on others (slaves), and use very simple
+cables to deliver signals using parallel ports, for example.
+
+Parallel port cable pinout::
+
+	pin	name	master      slave
+	1	STROBE	  *------     *
+	2	D0	  *     |     *
+	3	D1	  *     |     *
+	4	D2	  *     |     *
+	5	D3	  *     |     *
+	6	D4	  *     |     *
+	7	D5	  *     |     *
+	8	D6	  *     |     *
+	9	D7	  *     |     *
+	10	ACK	  *     ------*
+	11	BUSY	  *           *
+	12	PE	  *           *
+	13	SEL	  *           *
+	14	AUTOFD	  *           *
+	15	ERROR	  *           *
+	16	INIT	  *           *
+	17	SELIN	  *           *
+	18-25	GND	  *-----------*
+
+Please note that parallel port interrupt occurs only on high->low transition,
+so it is used for PPS assert edge. PPS clear edge can be determined only
+using polling in the interrupt handler which actually can be done way more
+precisely because interrupt handling delays can be quite big and random. So
+current parport PPS generator implementation (pps_gen_parport module) is
+geared towards using the clear edge for time synchronization.
+
+Clear edge polling is done with disabled interrupts so it's better to select
+delay between assert and clear edge as small as possible to reduce system
+latencies. But if it is too small slave won't be able to capture clear edge
+transition. The default of 30us should be good enough in most situations.
+The delay can be selected using 'delay' pps_gen_parport module parameter.
diff --git a/Documentation/driver-api/ptp.rst b/Documentation/driver-api/ptp.rst
new file mode 100644
index 000000000000..b6e65d66d37a
--- /dev/null
+++ b/Documentation/driver-api/ptp.rst
@@ -0,0 +1,96 @@
+:orphan:
+
+===========================================
+PTP hardware clock infrastructure for Linux
+===========================================
+
+  This patch set introduces support for IEEE 1588 PTP clocks in
+  Linux. Together with the SO_TIMESTAMPING socket options, this
+  presents a standardized method for developing PTP user space
+  programs, synchronizing Linux with external clocks, and using the
+  ancillary features of PTP hardware clocks.
+
+  A new class driver exports a kernel interface for specific clock
+  drivers and a user space interface. The infrastructure supports a
+  complete set of PTP hardware clock functionality.
+
+  + Basic clock operations
+    - Set time
+    - Get time
+    - Shift the clock by a given offset atomically
+    - Adjust clock frequency
+
+  + Ancillary clock features
+    - Time stamp external events
+    - Period output signals configurable from user space
+    - Synchronization of the Linux system time via the PPS subsystem
+
+PTP hardware clock kernel API
+=============================
+
+   A PTP clock driver registers itself with the class driver. The
+   class driver handles all of the dealings with user space. The
+   author of a clock driver need only implement the details of
+   programming the clock hardware. The clock driver notifies the class
+   driver of asynchronous events (alarms and external time stamps) via
+   a simple message passing interface.
+
+   The class driver supports multiple PTP clock drivers. In normal use
+   cases, only one PTP clock is needed. However, for testing and
+   development, it can be useful to have more than one clock in a
+   single system, in order to allow performance comparisons.
+
+PTP hardware clock user space API
+=================================
+
+   The class driver also creates a character device for each
+   registered clock. User space can use an open file descriptor from
+   the character device as a POSIX clock id and may call
+   clock_gettime, clock_settime, and clock_adjtime.  These calls
+   implement the basic clock operations.
+
+   User space programs may control the clock using standardized
+   ioctls. A program may query, enable, configure, and disable the
+   ancillary clock features. User space can receive time stamped
+   events via blocking read() and poll().
+
+Writing clock drivers
+=====================
+
+   Clock drivers include include/linux/ptp_clock_kernel.h and register
+   themselves by presenting a 'struct ptp_clock_info' to the
+   registration method. Clock drivers must implement all of the
+   functions in the interface. If a clock does not offer a particular
+   ancillary feature, then the driver should just return -EOPNOTSUPP
+   from those functions.
+
+   Drivers must ensure that all of the methods in interface are
+   reentrant. Since most hardware implementations treat the time value
+   as a 64 bit integer accessed as two 32 bit registers, drivers
+   should use spin_lock_irqsave/spin_unlock_irqrestore to protect
+   against concurrent access. This locking cannot be accomplished in
+   class driver, since the lock may also be needed by the clock
+   driver's interrupt service routine.
+
+Supported hardware
+==================
+
+   * Freescale eTSEC gianfar
+
+     - 2 Time stamp external triggers, programmable polarity (opt. interrupt)
+     - 2 Alarm registers (optional interrupt)
+     - 3 Periodic signals (optional interrupt)
+
+   * National DP83640
+
+     - 6 GPIOs programmable as inputs or outputs
+     - 6 GPIOs with dedicated functions (LED/JTAG/clock) can also be
+       used as general inputs or outputs
+     - GPIO inputs can time stamp external triggers
+     - GPIO outputs can produce periodic signals
+     - 1 interrupt pin
+
+   * Intel IXP465
+
+     - Auxiliary Slave/Master Mode Snapshot (optional interrupt)
+     - Target Time (optional interrupt)
diff --git a/Documentation/driver-api/target.rst b/Documentation/driver-api/target.rst
index 4363611dd86d..620ec6173a93 100644
--- a/Documentation/driver-api/target.rst
+++ b/Documentation/driver-api/target.rst
@@ -10,8 +10,8 @@ TBD
 Target core device interfaces
 =============================
 
-.. kernel-doc:: drivers/target/target_core_device.c
-    :export:
+This section is blank because no kerneldoc comments have been added to
+drivers/target/target_core_device.c.
 
 Target core transport interfaces
 ================================