docs: split up the driver book

We don't need to keep it as a single large file anymore; split it up so
that it is easier to manage and the individual sections can be read
directly as plain files.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/driver-api/basics.rst

+Driver Basics
+=============
+
+Driver Entry and Exit points
+----------------------------
+
+.. kernel-doc:: include/linux/init.h
+   :internal:
+
+Atomic and pointer manipulation
+-------------------------------
+
+.. kernel-doc:: arch/x86/include/asm/atomic.h
+   :internal:
+
+Delaying, scheduling, and timer routines
+----------------------------------------
+
+.. kernel-doc:: include/linux/sched.h
+   :internal:
+
+.. kernel-doc:: kernel/sched/core.c
+   :export:
+
+.. kernel-doc:: kernel/sched/cpupri.c
+   :internal:
+
+.. kernel-doc:: kernel/sched/fair.c
+   :internal:
+
+.. kernel-doc:: include/linux/completion.h
+   :internal:
+
+.. kernel-doc:: kernel/time/timer.c
+   :export:
+
+Wait queues and Wake events
+---------------------------
+
+.. kernel-doc:: include/linux/wait.h
+   :internal:
+
+.. kernel-doc:: kernel/sched/wait.c
+   :export:
+
+High-resolution timers
+----------------------
+
+.. kernel-doc:: include/linux/ktime.h
+   :internal:
+
+.. kernel-doc:: include/linux/hrtimer.h
+   :internal:
+
+.. kernel-doc:: kernel/time/hrtimer.c
+   :export:
+
+Workqueues and Kevents
+----------------------
+
+.. kernel-doc:: include/linux/workqueue.h
+   :internal:
+
+.. kernel-doc:: kernel/workqueue.c
+   :export:
+
+Internal Functions
+------------------
+
+.. kernel-doc:: kernel/exit.c
+   :internal:
+
+.. kernel-doc:: kernel/signal.c
+   :internal:
+
+.. kernel-doc:: include/linux/kthread.h
+   :internal:
+
+.. kernel-doc:: kernel/kthread.c
+   :export:
+
+Kernel objects manipulation
+---------------------------
+
+.. kernel-doc:: lib/kobject.c
+   :export:
+
+Kernel utility functions
+------------------------
+
+.. kernel-doc:: include/linux/kernel.h
+   :internal:
+
+.. kernel-doc:: kernel/printk/printk.c
+   :export:
+
+.. kernel-doc:: kernel/panic.c
+   :export:
+
+.. kernel-doc:: kernel/sys.c
+   :export:
+
+.. kernel-doc:: kernel/rcu/srcu.c
+   :export:
+
+.. kernel-doc:: kernel/rcu/tree.c
+   :export:
+
+.. kernel-doc:: kernel/rcu/tree_plugin.h
+   :export:
+
+.. kernel-doc:: kernel/rcu/update.c
+   :export:
+
+Device Resource Management
+--------------------------
+
+.. kernel-doc:: drivers/base/devres.c
+   :export:
+

Documentation/driver-api/frame-buffer.rst

+Frame Buffer Library
+====================
+
+The frame buffer drivers depend heavily on four data structures. These
+structures are declared in include/linux/fb.h. They are fb_info,
+fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. The last
+three can be made available to and from userland.
+
+fb_info defines the current state of a particular video card. Inside
+fb_info, there exists a fb_ops structure which is a collection of
+needed functions to make fbdev and fbcon work. fb_info is only visible
+to the kernel.
+
+fb_var_screeninfo is used to describe the features of a video card
+that are user defined. With fb_var_screeninfo, things such as depth
+and the resolution may be defined.
+
+The next structure is fb_fix_screeninfo. This defines the properties
+of a card that are created when a mode is set and can't be changed
+otherwise. A good example of this is the start of the frame buffer
+memory. This "locks" the address of the frame buffer memory, so that it
+cannot be changed or moved.
+
+The last structure is fb_monospecs. In the old API, there was little
+importance for fb_monospecs. This allowed for forbidden things such as
+setting a mode of 800x600 on a fix frequency monitor. With the new API,
+fb_monospecs prevents such things, and if used correctly, can prevent a
+monitor from being cooked. fb_monospecs will not be useful until
+kernels 2.5.x.
+
+Frame Buffer Memory
+-------------------
+
+.. kernel-doc:: drivers/video/fbdev/core/fbmem.c
+   :export:
+
+Frame Buffer Colormap
+---------------------
+
+.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c
+   :export:
+
+Frame Buffer Video Mode Database
+--------------------------------
+
+.. kernel-doc:: drivers/video/fbdev/core/modedb.c
+   :internal:
+
+.. kernel-doc:: drivers/video/fbdev/core/modedb.c
+   :export:
+
+Frame Buffer Macintosh Video Mode Database
+------------------------------------------
+
+.. kernel-doc:: drivers/video/fbdev/macmodes.c
+   :export:
+
+Frame Buffer Fonts
+------------------
+
+Refer to the file lib/fonts/fonts.c for more information.
+

Documentation/driver-api/index.rst

+========================================
+The Linux driver implementer's API guide
+========================================
+
+The kernel offers a wide variety of interfaces to support the development
+of device drivers.  This document is an only somewhat organized collection
+of some of those interfaces — it will hopefully get better over time!  The
+available subsections can be seen below.
+
+.. class:: toc-title
+
+	   Table of contents
+
+.. toctree::
+   :maxdepth: 2
+
+   basics
+   infrastructure
+   message-based
+   sound
+   frame-buffer
+   input
+   serial-interfaces
+   miscellaneous

Documentation/driver-api/infrastructure.rst

+Device drivers infrastructure
+=============================
+
+The Basic Device Driver-Model Structures
+----------------------------------------
+
+.. kernel-doc:: include/linux/device.h
+   :internal:
+
+Device Drivers Base
+-------------------
+
+.. kernel-doc:: drivers/base/init.c
+   :internal:
+
+.. kernel-doc:: drivers/base/driver.c
+   :export:
+
+.. kernel-doc:: drivers/base/core.c
+   :export:
+
+.. kernel-doc:: drivers/base/syscore.c
+   :export:
+
+.. kernel-doc:: drivers/base/class.c
+   :export:
+
+.. kernel-doc:: drivers/base/node.c
+   :internal:
+
+.. kernel-doc:: drivers/base/firmware_class.c
+   :export:
+
+.. kernel-doc:: drivers/base/transport_class.c
+   :export:
+
+.. kernel-doc:: drivers/base/dd.c
+   :export:
+
+.. kernel-doc:: include/linux/platform_device.h
+   :internal:
+
+.. kernel-doc:: drivers/base/platform.c
+   :export:
+
+.. kernel-doc:: drivers/base/bus.c
+   :export:
+
+Buffer Sharing and Synchronization
+----------------------------------
+
+The dma-buf subsystem provides the framework for sharing buffers for
+hardware (DMA) access across multiple device drivers and subsystems, and
+for synchronizing asynchronous hardware access.
+
+This is used, for example, by drm "prime" multi-GPU support, but is of
+course not limited to GPU use cases.
+
+The three main components of this are: (1) dma-buf, representing a
+sg_table and exposed to userspace as a file descriptor to allow passing
+between devices, (2) fence, which provides a mechanism to signal when
+one device as finished access, and (3) reservation, which manages the
+shared or exclusive fence(s) associated with the buffer.
+
+dma-buf
+~~~~~~~
+
+.. kernel-doc:: drivers/dma-buf/dma-buf.c
+   :export:
+
+.. kernel-doc:: include/linux/dma-buf.h
+   :internal:
+
+reservation
+~~~~~~~~~~~
+
+.. kernel-doc:: drivers/dma-buf/reservation.c
+   :doc: Reservation Object Overview
+
+.. kernel-doc:: drivers/dma-buf/reservation.c
+   :export:
+
+.. kernel-doc:: include/linux/reservation.h
+   :internal:
+
+fence
+~~~~~
+
+.. kernel-doc:: drivers/dma-buf/fence.c
+   :export:
+
+.. kernel-doc:: include/linux/fence.h
+   :internal:
+
+.. kernel-doc:: drivers/dma-buf/seqno-fence.c
+   :export:
+
+.. kernel-doc:: include/linux/seqno-fence.h
+   :internal:
+
+.. kernel-doc:: drivers/dma-buf/fence-array.c
+   :export:
+
+.. kernel-doc:: include/linux/fence-array.h
+   :internal:
+
+.. kernel-doc:: drivers/dma-buf/reservation.c
+   :export:
+
+.. kernel-doc:: include/linux/reservation.h
+   :internal:
+
+.. kernel-doc:: drivers/dma-buf/sync_file.c
+   :export:
+
+.. kernel-doc:: include/linux/sync_file.h
+   :internal:
+
+Device Drivers DMA Management
+-----------------------------
+
+.. kernel-doc:: drivers/base/dma-coherent.c
+   :export:
+
+.. kernel-doc:: drivers/base/dma-mapping.c
+   :export:
+
+Device Drivers Power Management
+-------------------------------
+
+.. kernel-doc:: drivers/base/power/main.c
+   :export:
+
+Device Drivers ACPI Support
+---------------------------
+
+.. kernel-doc:: drivers/acpi/scan.c
+   :export:
+
+.. kernel-doc:: drivers/acpi/scan.c
+   :internal:
+
+Device drivers PnP support
+--------------------------
+
+.. kernel-doc:: drivers/pnp/core.c
+   :internal:
+
+.. kernel-doc:: drivers/pnp/card.c
+   :export:
+
+.. kernel-doc:: drivers/pnp/driver.c
+   :internal:
+
+.. kernel-doc:: drivers/pnp/manager.c
+   :export:
+
+.. kernel-doc:: drivers/pnp/support.c
+   :export:
+
+Userspace IO devices
+--------------------
+
+.. kernel-doc:: drivers/uio/uio.c
+   :export:
+
+.. kernel-doc:: include/linux/uio_driver.h
+   :internal:
+

Documentation/driver-api/input.rst

+Input Subsystem
+===============
+
+Input core
+----------
+
+.. kernel-doc:: include/linux/input.h
+   :internal:
+
+.. kernel-doc:: drivers/input/input.c
+   :export:
+
+.. kernel-doc:: drivers/input/ff-core.c
+   :export:
+
+.. kernel-doc:: drivers/input/ff-memless.c
+   :export:
+
+Multitouch Library
+------------------
+
+.. kernel-doc:: include/linux/input/mt.h
+   :internal:
+
+.. kernel-doc:: drivers/input/input-mt.c
+   :export:
+
+Polled input devices
+--------------------
+
+.. kernel-doc:: include/linux/input-polldev.h
+   :internal:
+
+.. kernel-doc:: drivers/input/input-polldev.c
+   :export:
+
+Matrix keyboards/keypads
+------------------------
+
+.. kernel-doc:: include/linux/input/matrix_keypad.h
+   :internal:
+
+Sparse keymap support
+---------------------
+
+.. kernel-doc:: include/linux/input/sparse-keymap.h
+   :internal:
+
+.. kernel-doc:: drivers/input/sparse-keymap.c
+   :export:
+

Documentation/driver-api/message-based.rst

+Message-based devices
+=====================
+
+Fusion message devices
+----------------------
+
+.. kernel-doc:: drivers/message/fusion/mptbase.c
+   :export:
+
+.. kernel-doc:: drivers/message/fusion/mptbase.c
+   :internal:
+
+.. kernel-doc:: drivers/message/fusion/mptscsih.c
+   :export:
+
+.. kernel-doc:: drivers/message/fusion/mptscsih.c
+   :internal:
+
+.. kernel-doc:: drivers/message/fusion/mptctl.c
+   :internal:
+
+.. kernel-doc:: drivers/message/fusion/mptspi.c
+   :internal:
+
+.. kernel-doc:: drivers/message/fusion/mptfc.c
+   :internal:
+
+.. kernel-doc:: drivers/message/fusion/mptlan.c
+   :internal:
+

Documentation/driver-api/miscellaneous.rst

+Parallel Port Devices
+=====================
+
+.. kernel-doc:: include/linux/parport.h
+   :internal:
+
+.. kernel-doc:: drivers/parport/ieee1284.c
+   :export:
+
+.. kernel-doc:: drivers/parport/share.c
+   :export:
+
+.. kernel-doc:: drivers/parport/daisy.c
+   :internal:
+
+16x50 UART Driver
+=================
+
+.. kernel-doc:: drivers/tty/serial/serial_core.c
+   :export:
+
+.. kernel-doc:: drivers/tty/serial/8250/8250_core.c
+   :export:
+
+Pulse-Width Modulation (PWM)
+============================
+
+Pulse-width modulation is a modulation technique primarily used to
+control power supplied to electrical devices.
+
+The PWM framework provides an abstraction for providers and consumers of
+PWM signals. A controller that provides one or more PWM signals is
+registered as :c:type:`struct pwm_chip <pwm_chip>`. Providers
+are expected to embed this structure in a driver-specific structure.
+This structure contains fields that describe a particular chip.
+
+A chip exposes one or more PWM signal sources, each of which exposed as
+a :c:type:`struct pwm_device <pwm_device>`. Operations can be
+performed on PWM devices to control the period, duty cycle, polarity and
+active state of the signal.
+
+Note that PWM devices are exclusive resources: they can always only be
+used by one consumer at a time.
+
+.. kernel-doc:: include/linux/pwm.h
+   :internal:
+
+.. kernel-doc:: drivers/pwm/core.c
+   :export:
+   

Documentation/driver-api/sound.rst

+Sound Devices
+=============
+
+.. kernel-doc:: include/sound/core.h
+   :internal:
+
+.. kernel-doc:: sound/sound_core.c
+   :export:
+
+.. kernel-doc:: include/sound/pcm.h
+   :internal:
+
+.. kernel-doc:: sound/core/pcm.c
+   :export:
+
+.. kernel-doc:: sound/core/device.c
+   :export:
+
+.. kernel-doc:: sound/core/info.c
+   :export:
+
+.. kernel-doc:: sound/core/rawmidi.c
+   :export:
+
+.. kernel-doc:: sound/core/sound.c
+   :export:
+
+.. kernel-doc:: sound/core/memory.c
+   :export:
+
+.. kernel-doc:: sound/core/pcm_memory.c
+   :export:
+
+.. kernel-doc:: sound/core/init.c
+   :export:
+
+.. kernel-doc:: sound/core/isadma.c
+   :export:
+
+.. kernel-doc:: sound/core/control.c
+   :export:
+
+.. kernel-doc:: sound/core/pcm_lib.c
+   :export:
+
+.. kernel-doc:: sound/core/hwdep.c
+   :export:
+
+.. kernel-doc:: sound/core/pcm_native.c
+   :export:
+
+.. kernel-doc:: sound/core/memalloc.c
+   :export:
+

Documentation/index.rst

@@ -13,7 +13,7 @@ Contents:
 
    kernel-documentation
    dev-tools/tools
-   driver-api/drivers
+   driver-api/index
    media/index
    gpu/index