docs: ptp.txt: convert to ReST and move to driver-api

The conversion is trivial: just adjust title markups.

In order to avoid conflicts, let's add an :orphan: tag
to it, to be removed when this file gets added to the
driver-api book.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 0 insertions, 86 deletions

diff --git a/Documentation/ptp/ptp.txt b/Documentation/ptp/ptp.txt
deleted file mode 100644
index 11e904ee073f..000000000000
--- a/Documentation/ptp/ptp.txt
+++ /dev/null
@@ -1,86 +0,0 @@
-
-* 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)