linux/Documentation/DocBook/device-drivers.tmpl
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   1<?xml version="1.0" encoding="UTF-8"?>
   2<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
   3        "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
   4
   5<book id="LinuxDriversAPI">
   6 <bookinfo>
   7  <title>Linux Device Drivers</title>
   8
   9  <legalnotice>
  10   <para>
  11     This documentation is free software; you can redistribute
  12     it and/or modify it under the terms of the GNU General Public
  13     License as published by the Free Software Foundation; either
  14     version 2 of the License, or (at your option) any later
  15     version.
  16   </para>
  17
  18   <para>
  19     This program is distributed in the hope that it will be
  20     useful, but WITHOUT ANY WARRANTY; without even the implied
  21     warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  22     See the GNU General Public License for more details.
  23   </para>
  24
  25   <para>
  26     You should have received a copy of the GNU General Public
  27     License along with this program; if not, write to the Free
  28     Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  29     MA 02111-1307 USA
  30   </para>
  31
  32   <para>
  33     For more details see the file COPYING in the source
  34     distribution of Linux.
  35   </para>
  36  </legalnotice>
  37 </bookinfo>
  38
  39<toc></toc>
  40
  41  <chapter id="Basics">
  42     <title>Driver Basics</title>
  43     <sect1><title>Driver Entry and Exit points</title>
  44!Iinclude/linux/init.h
  45     </sect1>
  46
  47     <sect1><title>Atomic and pointer manipulation</title>
  48!Iarch/x86/include/asm/atomic.h
  49     </sect1>
  50
  51     <sect1><title>Delaying, scheduling, and timer routines</title>
  52!Iinclude/linux/sched.h
  53!Ekernel/sched/core.c
  54!Ikernel/sched/cpupri.c
  55!Ikernel/sched/fair.c
  56!Iinclude/linux/completion.h
  57!Ekernel/timer.c
  58     </sect1>
  59     <sect1><title>Wait queues and Wake events</title>
  60!Iinclude/linux/wait.h
  61!Ekernel/wait.c
  62     </sect1>
  63     <sect1><title>High-resolution timers</title>
  64!Iinclude/linux/ktime.h
  65!Iinclude/linux/hrtimer.h
  66!Ekernel/hrtimer.c
  67     </sect1>
  68     <sect1><title>Workqueues and Kevents</title>
  69!Ekernel/workqueue.c
  70     </sect1>
  71     <sect1><title>Internal Functions</title>
  72!Ikernel/exit.c
  73!Ikernel/signal.c
  74!Iinclude/linux/kthread.h
  75!Ekernel/kthread.c
  76     </sect1>
  77
  78     <sect1><title>Kernel objects manipulation</title>
  79<!--
  80X!Iinclude/linux/kobject.h
  81-->
  82!Elib/kobject.c
  83     </sect1>
  84
  85     <sect1><title>Kernel utility functions</title>
  86!Iinclude/linux/kernel.h
  87!Ekernel/printk.c
  88!Ekernel/panic.c
  89!Ekernel/sys.c
  90!Ekernel/rcupdate.c
  91     </sect1>
  92
  93     <sect1><title>Device Resource Management</title>
  94!Edrivers/base/devres.c
  95     </sect1>
  96
  97  </chapter>
  98
  99  <chapter id="devdrivers">
 100     <title>Device drivers infrastructure</title>
 101     <sect1><title>The Basic Device Driver-Model Structures </title>
 102!Iinclude/linux/device.h
 103     </sect1>
 104     <sect1><title>Device Drivers Base</title>
 105!Idrivers/base/init.c
 106!Edrivers/base/driver.c
 107!Edrivers/base/core.c
 108!Edrivers/base/syscore.c
 109!Edrivers/base/class.c
 110!Idrivers/base/node.c
 111!Edrivers/base/firmware_class.c
 112!Edrivers/base/transport_class.c
 113<!-- Cannot be included, because
 114     attribute_container_add_class_device_adapter
 115 and attribute_container_classdev_to_container
 116     exceed allowed 44 characters maximum
 117X!Edrivers/base/attribute_container.c
 118-->
 119!Edrivers/base/dd.c
 120<!--
 121X!Edrivers/base/interface.c
 122-->
 123!Iinclude/linux/platform_device.h
 124!Edrivers/base/platform.c
 125!Edrivers/base/bus.c
 126     </sect1>
 127     <sect1><title>Device Drivers DMA Management</title>
 128!Edrivers/base/dma-buf.c
 129!Edrivers/base/dma-coherent.c
 130!Edrivers/base/dma-mapping.c
 131     </sect1>
 132     <sect1><title>Device Drivers Power Management</title>
 133!Edrivers/base/power/main.c
 134     </sect1>
 135     <sect1><title>Device Drivers ACPI Support</title>
 136<!-- Internal functions only
 137X!Edrivers/acpi/sleep/main.c
 138X!Edrivers/acpi/sleep/wakeup.c
 139X!Edrivers/acpi/motherboard.c
 140X!Edrivers/acpi/bus.c
 141-->
 142!Edrivers/acpi/scan.c
 143!Idrivers/acpi/scan.c
 144<!-- No correct structured comments
 145X!Edrivers/acpi/pci_bind.c
 146-->
 147     </sect1>
 148     <sect1><title>Device drivers PnP support</title>
 149!Idrivers/pnp/core.c
 150<!-- No correct structured comments
 151X!Edrivers/pnp/system.c
 152 -->
 153!Edrivers/pnp/card.c
 154!Idrivers/pnp/driver.c
 155!Edrivers/pnp/manager.c
 156!Edrivers/pnp/support.c
 157     </sect1>
 158     <sect1><title>Userspace IO devices</title>
 159!Edrivers/uio/uio.c
 160!Iinclude/linux/uio_driver.h
 161     </sect1>
 162  </chapter>
 163
 164  <chapter id="parportdev">
 165     <title>Parallel Port Devices</title>
 166!Iinclude/linux/parport.h
 167!Edrivers/parport/ieee1284.c
 168!Edrivers/parport/share.c
 169!Idrivers/parport/daisy.c
 170  </chapter>
 171
 172  <chapter id="message_devices">
 173        <title>Message-based devices</title>
 174     <sect1><title>Fusion message devices</title>
 175!Edrivers/message/fusion/mptbase.c
 176!Idrivers/message/fusion/mptbase.c
 177!Edrivers/message/fusion/mptscsih.c
 178!Idrivers/message/fusion/mptscsih.c
 179!Idrivers/message/fusion/mptctl.c
 180!Idrivers/message/fusion/mptspi.c
 181!Idrivers/message/fusion/mptfc.c
 182!Idrivers/message/fusion/mptlan.c
 183     </sect1>
 184     <sect1><title>I2O message devices</title>
 185!Iinclude/linux/i2o.h
 186!Idrivers/message/i2o/core.h
 187!Edrivers/message/i2o/iop.c
 188!Idrivers/message/i2o/iop.c
 189!Idrivers/message/i2o/config-osm.c
 190!Edrivers/message/i2o/exec-osm.c
 191!Idrivers/message/i2o/exec-osm.c
 192!Idrivers/message/i2o/bus-osm.c
 193!Edrivers/message/i2o/device.c
 194!Idrivers/message/i2o/device.c
 195!Idrivers/message/i2o/driver.c
 196!Idrivers/message/i2o/pci.c
 197!Idrivers/message/i2o/i2o_block.c
 198!Idrivers/message/i2o/i2o_scsi.c
 199!Idrivers/message/i2o/i2o_proc.c
 200     </sect1>
 201  </chapter>
 202
 203  <chapter id="snddev">
 204     <title>Sound Devices</title>
 205!Iinclude/sound/core.h
 206!Esound/sound_core.c
 207!Iinclude/sound/pcm.h
 208!Esound/core/pcm.c
 209!Esound/core/device.c
 210!Esound/core/info.c
 211!Esound/core/rawmidi.c
 212!Esound/core/sound.c
 213!Esound/core/memory.c
 214!Esound/core/pcm_memory.c
 215!Esound/core/init.c
 216!Esound/core/isadma.c
 217!Esound/core/control.c
 218!Esound/core/pcm_lib.c
 219!Esound/core/hwdep.c
 220!Esound/core/pcm_native.c
 221!Esound/core/memalloc.c
 222<!-- FIXME: Removed for now since no structured comments in source
 223X!Isound/sound_firmware.c
 224-->
 225  </chapter>
 226
 227  <chapter id="uart16x50">
 228     <title>16x50 UART Driver</title>
 229!Edrivers/tty/serial/serial_core.c
 230!Edrivers/tty/serial/8250/8250.c
 231  </chapter>
 232
 233  <chapter id="fbdev">
 234     <title>Frame Buffer Library</title>
 235
 236     <para>
 237       The frame buffer drivers depend heavily on four data structures.
 238       These structures are declared in include/linux/fb.h.  They are
 239       fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs.
 240       The last three can be made available to and from userland.
 241     </para>
 242
 243     <para>
 244       fb_info defines the current state of a particular video card.
 245       Inside fb_info, there exists a fb_ops structure which is a
 246       collection of needed functions to make fbdev and fbcon work.
 247       fb_info is only visible to the kernel.
 248     </para>
 249
 250     <para>
 251       fb_var_screeninfo is used to describe the features of a video card
 252       that are user defined.  With fb_var_screeninfo, things such as
 253       depth and the resolution may be defined.
 254     </para>
 255
 256     <para>
 257       The next structure is fb_fix_screeninfo. This defines the
 258       properties of a card that are created when a mode is set and can't
 259       be changed otherwise.  A good example of this is the start of the
 260       frame buffer memory.  This "locks" the address of the frame buffer
 261       memory, so that it cannot be changed or moved.
 262     </para>
 263
 264     <para>
 265       The last structure is fb_monospecs. In the old API, there was
 266       little importance for fb_monospecs. This allowed for forbidden things
 267       such as setting a mode of 800x600 on a fix frequency monitor. With
 268       the new API, fb_monospecs prevents such things, and if used
 269       correctly, can prevent a monitor from being cooked.  fb_monospecs
 270       will not be useful until kernels 2.5.x.
 271     </para>
 272
 273     <sect1><title>Frame Buffer Memory</title>
 274!Edrivers/video/fbmem.c
 275     </sect1>
 276<!--
 277     <sect1><title>Frame Buffer Console</title>
 278X!Edrivers/video/console/fbcon.c
 279     </sect1>
 280-->
 281     <sect1><title>Frame Buffer Colormap</title>
 282!Edrivers/video/fbcmap.c
 283     </sect1>
 284<!-- FIXME:
 285  drivers/video/fbgen.c has no docs, which stuffs up the sgml.  Comment
 286  out until somebody adds docs.  KAO
 287     <sect1><title>Frame Buffer Generic Functions</title>
 288X!Idrivers/video/fbgen.c
 289     </sect1>
 290KAO -->
 291     <sect1><title>Frame Buffer Video Mode Database</title>
 292!Idrivers/video/modedb.c
 293!Edrivers/video/modedb.c
 294     </sect1>
 295     <sect1><title>Frame Buffer Macintosh Video Mode Database</title>
 296!Edrivers/video/macmodes.c
 297     </sect1>
 298     <sect1><title>Frame Buffer Fonts</title>
 299        <para>
 300           Refer to the file drivers/video/console/fonts.c for more information.
 301        </para>
 302<!-- FIXME: Removed for now since no structured comments in source
 303X!Idrivers/video/console/fonts.c
 304-->
 305     </sect1>
 306  </chapter>
 307
 308  <chapter id="input_subsystem">
 309     <title>Input Subsystem</title>
 310     <sect1><title>Input core</title>
 311!Iinclude/linux/input.h
 312!Edrivers/input/input.c
 313!Edrivers/input/ff-core.c
 314!Edrivers/input/ff-memless.c
 315     </sect1>
 316     <sect1><title>Multitouch Library</title>
 317!Iinclude/linux/input/mt.h
 318!Edrivers/input/input-mt.c
 319     </sect1>
 320     <sect1><title>Polled input devices</title>
 321!Iinclude/linux/input-polldev.h
 322!Edrivers/input/input-polldev.c
 323     </sect1>
 324     <sect1><title>Matrix keyboars/keypads</title>
 325!Iinclude/linux/input/matrix_keypad.h
 326     </sect1>
 327     <sect1><title>Sparse keymap support</title>
 328!Iinclude/linux/input/sparse-keymap.h
 329!Edrivers/input/sparse-keymap.c
 330     </sect1>
 331  </chapter>
 332
 333  <chapter id="spi">
 334      <title>Serial Peripheral Interface (SPI)</title>
 335  <para>
 336        SPI is the "Serial Peripheral Interface", widely used with
 337        embedded systems because it is a simple and efficient
 338        interface:  basically a multiplexed shift register.
 339        Its three signal wires hold a clock (SCK, often in the range
 340        of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and
 341        a "Master In, Slave Out" (MISO) data line.
 342        SPI is a full duplex protocol; for each bit shifted out the
 343        MOSI line (one per clock) another is shifted in on the MISO line.
 344        Those bits are assembled into words of various sizes on the
 345        way to and from system memory.
 346        An additional chipselect line is usually active-low (nCS);
 347        four signals are normally used for each peripheral, plus
 348        sometimes an interrupt.
 349  </para>
 350  <para>
 351        The SPI bus facilities listed here provide a generalized
 352        interface to declare SPI busses and devices, manage them
 353        according to the standard Linux driver model, and perform
 354        input/output operations.
 355        At this time, only "master" side interfaces are supported,
 356        where Linux talks to SPI peripherals and does not implement
 357        such a peripheral itself.
 358        (Interfaces to support implementing SPI slaves would
 359        necessarily look different.)
 360  </para>
 361  <para>
 362        The programming interface is structured around two kinds of driver,
 363        and two kinds of device.
 364        A "Controller Driver" abstracts the controller hardware, which may
 365        be as simple as a set of GPIO pins or as complex as a pair of FIFOs
 366        connected to dual DMA engines on the other side of the SPI shift
 367        register (maximizing throughput).  Such drivers bridge between
 368        whatever bus they sit on (often the platform bus) and SPI, and
 369        expose the SPI side of their device as a
 370        <structname>struct spi_master</structname>.
 371        SPI devices are children of that master, represented as a
 372        <structname>struct spi_device</structname> and manufactured from
 373        <structname>struct spi_board_info</structname> descriptors which
 374        are usually provided by board-specific initialization code.
 375        A <structname>struct spi_driver</structname> is called a
 376        "Protocol Driver", and is bound to a spi_device using normal
 377        driver model calls.
 378  </para>
 379  <para>
 380        The I/O model is a set of queued messages.  Protocol drivers
 381        submit one or more <structname>struct spi_message</structname>
 382        objects, which are processed and completed asynchronously.
 383        (There are synchronous wrappers, however.)  Messages are
 384        built from one or more <structname>struct spi_transfer</structname>
 385        objects, each of which wraps a full duplex SPI transfer.
 386        A variety of protocol tweaking options are needed, because
 387        different chips adopt very different policies for how they
 388        use the bits transferred with SPI.
 389  </para>
 390!Iinclude/linux/spi/spi.h
 391!Fdrivers/spi/spi.c spi_register_board_info
 392!Edrivers/spi/spi.c
 393  </chapter>
 394
 395  <chapter id="i2c">
 396     <title>I<superscript>2</superscript>C and SMBus Subsystem</title>
 397
 398     <para>
 399        I<superscript>2</superscript>C (or without fancy typography, "I2C")
 400        is an acronym for the "Inter-IC" bus, a simple bus protocol which is
 401        widely used where low data rate communications suffice.
 402        Since it's also a licensed trademark, some vendors use another
 403        name (such as "Two-Wire Interface", TWI) for the same bus.
 404        I2C only needs two signals (SCL for clock, SDA for data), conserving
 405        board real estate and minimizing signal quality issues.
 406        Most I2C devices use seven bit addresses, and bus speeds of up
 407        to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet
 408        found wide use.
 409        I2C is a multi-master bus; open drain signaling is used to
 410        arbitrate between masters, as well as to handshake and to
 411        synchronize clocks from slower clients.
 412     </para>
 413
 414     <para>
 415        The Linux I2C programming interfaces support only the master
 416        side of bus interactions, not the slave side.
 417        The programming interface is structured around two kinds of driver,
 418        and two kinds of device.
 419        An I2C "Adapter Driver" abstracts the controller hardware; it binds
 420        to a physical device (perhaps a PCI device or platform_device) and
 421        exposes a <structname>struct i2c_adapter</structname> representing
 422        each I2C bus segment it manages.
 423        On each I2C bus segment will be I2C devices represented by a
 424        <structname>struct i2c_client</structname>.  Those devices will
 425        be bound to a <structname>struct i2c_driver</structname>,
 426        which should follow the standard Linux driver model.
 427        (At this writing, a legacy model is more widely used.)
 428        There are functions to perform various I2C protocol operations; at
 429        this writing all such functions are usable only from task context.
 430     </para>
 431
 432     <para>
 433        The System Management Bus (SMBus) is a sibling protocol.  Most SMBus
 434        systems are also I2C conformant.  The electrical constraints are
 435        tighter for SMBus, and it standardizes particular protocol messages
 436        and idioms.  Controllers that support I2C can also support most
 437        SMBus operations, but SMBus controllers don't support all the protocol
 438        options that an I2C controller will.
 439        There are functions to perform various SMBus protocol operations,
 440        either using I2C primitives or by issuing SMBus commands to
 441        i2c_adapter devices which don't support those I2C operations.
 442     </para>
 443
 444!Iinclude/linux/i2c.h
 445!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info
 446!Edrivers/i2c/i2c-core.c
 447  </chapter>
 448
 449  <chapter id="hsi">
 450     <title>High Speed Synchronous Serial Interface (HSI)</title>
 451
 452     <para>
 453        High Speed Synchronous Serial Interface (HSI) is a
 454        serial interface mainly used for connecting application
 455        engines (APE) with cellular modem engines (CMT) in cellular
 456        handsets.
 457
 458        HSI provides multiplexing for up to 16 logical channels,
 459        low-latency and full duplex communication.
 460     </para>
 461
 462!Iinclude/linux/hsi/hsi.h
 463!Edrivers/hsi/hsi.c
 464  </chapter>
 465
 466</book>
 467
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