Documentation/DocBook/device-drivers.tmpl

   1 <?xml version="1.0" encoding="UTF-8"?>
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   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 <!--
  80 X!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 !Edrivers/base/driver.c
 106 !Edrivers/base/core.c
 107 !Edrivers/base/class.c
 108 !Edrivers/base/firmware_class.c
 109 !Edrivers/base/transport_class.c
 110 <!-- Cannot be included, because
 111      attribute_container_add_class_device_adapter
 112  and attribute_container_classdev_to_container
 113      exceed allowed 44 characters maximum
 114 X!Edrivers/base/attribute_container.c
 115 -->
 116 !Edrivers/base/sys.c
 117 <!--
 118 X!Edrivers/base/interface.c
 119 -->
 120 !Iinclude/linux/platform_device.h
 121 !Edrivers/base/platform.c
 122 !Edrivers/base/bus.c
 123      </sect1>
 124      <sect1><title>Device Drivers Power Management</title>
 125 !Edrivers/base/power/main.c
 126      </sect1>
 127      <sect1><title>Device Drivers ACPI Support</title>
 128 <!-- Internal functions only
 129 X!Edrivers/acpi/sleep/main.c
 130 X!Edrivers/acpi/sleep/wakeup.c
 131 X!Edrivers/acpi/motherboard.c
 132 X!Edrivers/acpi/bus.c
 133 -->
 134 !Edrivers/acpi/scan.c
 135 !Idrivers/acpi/scan.c
 136 <!-- No correct structured comments
 137 X!Edrivers/acpi/pci_bind.c
 138 -->
 139      </sect1>
 140      <sect1><title>Device drivers PnP support</title>
 141 !Idrivers/pnp/core.c
 142 <!-- No correct structured comments
 143 X!Edrivers/pnp/system.c
 144  -->
 145 !Edrivers/pnp/card.c
 146 !Idrivers/pnp/driver.c
 147 !Edrivers/pnp/manager.c
 148 !Edrivers/pnp/support.c
 149      </sect1>
 150      <sect1><title>Userspace IO devices</title>
 151 !Edrivers/uio/uio.c
 152 !Iinclude/linux/uio_driver.h
 153      </sect1>
 154   </chapter>
 155
 156   <chapter id="parportdev">
 157      <title>Parallel Port Devices</title>
 158 !Iinclude/linux/parport.h
 159 !Edrivers/parport/ieee1284.c
 160 !Edrivers/parport/share.c
 161 !Idrivers/parport/daisy.c
 162   </chapter>
 163
 164   <chapter id="message_devices">
 165         <title>Message-based devices</title>
 166      <sect1><title>Fusion message devices</title>
 167 !Edrivers/message/fusion/mptbase.c
 168 !Idrivers/message/fusion/mptbase.c
 169 !Edrivers/message/fusion/mptscsih.c
 170 !Idrivers/message/fusion/mptscsih.c
 171 !Idrivers/message/fusion/mptctl.c
 172 !Idrivers/message/fusion/mptspi.c
 173 !Idrivers/message/fusion/mptfc.c
 174 !Idrivers/message/fusion/mptlan.c
 175      </sect1>
 176      <sect1><title>I2O message devices</title>
 177 !Iinclude/linux/i2o.h
 178 !Idrivers/message/i2o/core.h
 179 !Edrivers/message/i2o/iop.c
 180 !Idrivers/message/i2o/iop.c
 181 !Idrivers/message/i2o/config-osm.c
 182 !Edrivers/message/i2o/exec-osm.c
 183 !Idrivers/message/i2o/exec-osm.c
 184 !Idrivers/message/i2o/bus-osm.c
 185 !Edrivers/message/i2o/device.c
 186 !Idrivers/message/i2o/device.c
 187 !Idrivers/message/i2o/driver.c
 188 !Idrivers/message/i2o/pci.c
 189 !Idrivers/message/i2o/i2o_block.c
 190 !Idrivers/message/i2o/i2o_scsi.c
 191 !Idrivers/message/i2o/i2o_proc.c
 192      </sect1>
 193   </chapter>
 194
 195   <chapter id="snddev">
 196      <title>Sound Devices</title>
 197 !Iinclude/sound/core.h
 198 !Esound/sound_core.c
 199 !Iinclude/sound/pcm.h
 200 !Esound/core/pcm.c
 201 !Esound/core/device.c
 202 !Esound/core/info.c
 203 !Esound/core/rawmidi.c
 204 !Esound/core/sound.c
 205 !Esound/core/memory.c
 206 !Esound/core/pcm_memory.c
 207 !Esound/core/init.c
 208 !Esound/core/isadma.c
 209 !Esound/core/control.c
 210 !Esound/core/pcm_lib.c
 211 !Esound/core/hwdep.c
 212 !Esound/core/pcm_native.c
 213 !Esound/core/memalloc.c
 214 <!-- FIXME: Removed for now since no structured comments in source
 215 X!Isound/sound_firmware.c
 216 -->
 217   </chapter>
 218
 219   <chapter id="uart16x50">
 220      <title>16x50 UART Driver</title>
 221 !Edrivers/tty/serial/serial_core.c
 222 !Edrivers/tty/serial/8250.c
 223   </chapter>
 224
 225   <chapter id="fbdev">
 226      <title>Frame Buffer Library</title>
 227
 228      <para>
 229        The frame buffer drivers depend heavily on four data structures.
 230        These structures are declared in include/linux/fb.h.  They are
 231        fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs.
 232        The last three can be made available to and from userland.
 233      </para>
 234
 235      <para>
 236        fb_info defines the current state of a particular video card.
 237        Inside fb_info, there exists a fb_ops structure which is a
 238        collection of needed functions to make fbdev and fbcon work.
 239        fb_info is only visible to the kernel.
 240      </para>
 241
 242      <para>
 243        fb_var_screeninfo is used to describe the features of a video card
 244        that are user defined.  With fb_var_screeninfo, things such as
 245        depth and the resolution may be defined.
 246      </para>
 247
 248      <para>
 249        The next structure is fb_fix_screeninfo. This defines the
 250        properties of a card that are created when a mode is set and can't
 251        be changed otherwise.  A good example of this is the start of the
 252        frame buffer memory.  This "locks" the address of the frame buffer
 253        memory, so that it cannot be changed or moved.
 254      </para>
 255
 256      <para>
 257        The last structure is fb_monospecs. In the old API, there was
 258        little importance for fb_monospecs. This allowed for forbidden things
 259        such as setting a mode of 800x600 on a fix frequency monitor. With
 260        the new API, fb_monospecs prevents such things, and if used
 261        correctly, can prevent a monitor from being cooked.  fb_monospecs
 262        will not be useful until kernels 2.5.x.
 263      </para>
 264
 265      <sect1><title>Frame Buffer Memory</title>
 266 !Edrivers/video/fbmem.c
 267      </sect1>
 268 <!--
 269      <sect1><title>Frame Buffer Console</title>
 270 X!Edrivers/video/console/fbcon.c
 271      </sect1>
 272 -->
 273      <sect1><title>Frame Buffer Colormap</title>
 274 !Edrivers/video/fbcmap.c
 275      </sect1>
 276 <!-- FIXME:
 277   drivers/video/fbgen.c has no docs, which stuffs up the sgml.  Comment
 278   out until somebody adds docs.  KAO
 279      <sect1><title>Frame Buffer Generic Functions</title>
 280 X!Idrivers/video/fbgen.c
 281      </sect1>
 282 KAO -->
 283      <sect1><title>Frame Buffer Video Mode Database</title>
 284 !Idrivers/video/modedb.c
 285 !Edrivers/video/modedb.c
 286      </sect1>
 287      <sect1><title>Frame Buffer Macintosh Video Mode Database</title>
 288 !Edrivers/video/macmodes.c
 289      </sect1>
 290      <sect1><title>Frame Buffer Fonts</title>
 291         <para>
 292            Refer to the file drivers/video/console/fonts.c for more information.
 293         </para>
 294 <!-- FIXME: Removed for now since no structured comments in source
 295 X!Idrivers/video/console/fonts.c
 296 -->
 297      </sect1>
 298   </chapter>
 299
 300   <chapter id="input_subsystem">
 301      <title>Input Subsystem</title>
 302      <sect1><title>Input core</title>
 303 !Iinclude/linux/input.h
 304 !Edrivers/input/input.c
 305 !Edrivers/input/ff-core.c
 306 !Edrivers/input/ff-memless.c
 307      </sect1>
 308      <sect1><title>Multitouch Library</title>
 309 !Iinclude/linux/input/mt.h
 310 !Edrivers/input/input-mt.c
 311      </sect1>
 312      <sect1><title>Polled input devices</title>
 313 !Iinclude/linux/input-polldev.h
 314 !Edrivers/input/input-polldev.c
 315      </sect1>
 316      <sect1><title>Matrix keyboars/keypads</title>
 317 !Iinclude/linux/input/matrix_keypad.h
 318      </sect1>
 319      <sect1><title>Sparse keymap support</title>
 320 !Iinclude/linux/input/sparse-keymap.h
 321 !Edrivers/input/sparse-keymap.c
 322      </sect1>
 323   </chapter>
 324
 325   <chapter id="spi">
 326       <title>Serial Peripheral Interface (SPI)</title>
 327   <para>
 328         SPI is the "Serial Peripheral Interface", widely used with
 329         embedded systems because it is a simple and efficient
 330         interface:  basically a multiplexed shift register.
 331         Its three signal wires hold a clock (SCK, often in the range
 332         of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and
 333         a "Master In, Slave Out" (MISO) data line.
 334         SPI is a full duplex protocol; for each bit shifted out the
 335         MOSI line (one per clock) another is shifted in on the MISO line.
 336         Those bits are assembled into words of various sizes on the
 337         way to and from system memory.
 338         An additional chipselect line is usually active-low (nCS);
 339         four signals are normally used for each peripheral, plus
 340         sometimes an interrupt.
 341   </para>
 342   <para>
 343         The SPI bus facilities listed here provide a generalized
 344         interface to declare SPI busses and devices, manage them
 345         according to the standard Linux driver model, and perform
 346         input/output operations.
 347         At this time, only "master" side interfaces are supported,
 348         where Linux talks to SPI peripherals and does not implement
 349         such a peripheral itself.
 350         (Interfaces to support implementing SPI slaves would
 351         necessarily look different.)
 352   </para>
 353   <para>
 354         The programming interface is structured around two kinds of driver,
 355         and two kinds of device.
 356         A "Controller Driver" abstracts the controller hardware, which may
 357         be as simple as a set of GPIO pins or as complex as a pair of FIFOs
 358         connected to dual DMA engines on the other side of the SPI shift
 359         register (maximizing throughput).  Such drivers bridge between
 360         whatever bus they sit on (often the platform bus) and SPI, and
 361         expose the SPI side of their device as a
 362         <structname>struct spi_master</structname>.
 363         SPI devices are children of that master, represented as a
 364         <structname>struct spi_device</structname> and manufactured from
 365         <structname>struct spi_board_info</structname> descriptors which
 366         are usually provided by board-specific initialization code.
 367         A <structname>struct spi_driver</structname> is called a
 368         "Protocol Driver", and is bound to a spi_device using normal
 369         driver model calls.
 370   </para>
 371   <para>
 372         The I/O model is a set of queued messages.  Protocol drivers
 373         submit one or more <structname>struct spi_message</structname>
 374         objects, which are processed and completed asynchronously.
 375         (There are synchronous wrappers, however.)  Messages are
 376         built from one or more <structname>struct spi_transfer</structname>
 377         objects, each of which wraps a full duplex SPI transfer.
 378         A variety of protocol tweaking options are needed, because
 379         different chips adopt very different policies for how they
 380         use the bits transferred with SPI.
 381   </para>
 382 !Iinclude/linux/spi/spi.h
 383 !Fdrivers/spi/spi.c spi_register_board_info
 384 !Edrivers/spi/spi.c
 385   </chapter>
 386
 387   <chapter id="i2c">
 388      <title>I<superscript>2</superscript>C and SMBus Subsystem</title>
 389
 390      <para>
 391         I<superscript>2</superscript>C (or without fancy typography, "I2C")
 392         is an acronym for the "Inter-IC" bus, a simple bus protocol which is
 393         widely used where low data rate communications suffice.
 394         Since it's also a licensed trademark, some vendors use another
 395         name (such as "Two-Wire Interface", TWI) for the same bus.
 396         I2C only needs two signals (SCL for clock, SDA for data), conserving
 397         board real estate and minimizing signal quality issues.
 398         Most I2C devices use seven bit addresses, and bus speeds of up
 399         to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet
 400         found wide use.
 401         I2C is a multi-master bus; open drain signaling is used to
 402         arbitrate between masters, as well as to handshake and to
 403         synchronize clocks from slower clients.
 404      </para>
 405
 406      <para>
 407         The Linux I2C programming interfaces support only the master
 408         side of bus interactions, not the slave side.
 409         The programming interface is structured around two kinds of driver,
 410         and two kinds of device.
 411         An I2C "Adapter Driver" abstracts the controller hardware; it binds
 412         to a physical device (perhaps a PCI device or platform_device) and
 413         exposes a <structname>struct i2c_adapter</structname> representing
 414         each I2C bus segment it manages.
 415         On each I2C bus segment will be I2C devices represented by a
 416         <structname>struct i2c_client</structname>.  Those devices will
 417         be bound to a <structname>struct i2c_driver</structname>,
 418         which should follow the standard Linux driver model.
 419         (At this writing, a legacy model is more widely used.)
 420         There are functions to perform various I2C protocol operations; at
 421         this writing all such functions are usable only from task context.
 422      </para>
 423
 424      <para>
 425         The System Management Bus (SMBus) is a sibling protocol.  Most SMBus
 426         systems are also I2C conformant.  The electrical constraints are
 427         tighter for SMBus, and it standardizes particular protocol messages
 428         and idioms.  Controllers that support I2C can also support most
 429         SMBus operations, but SMBus controllers don't support all the protocol
 430         options that an I2C controller will.
 431         There are functions to perform various SMBus protocol operations,
 432         either using I2C primitives or by issuing SMBus commands to
 433         i2c_adapter devices which don't support those I2C operations.
 434      </para>
 435
 436 !Iinclude/linux/i2c.h
 437 !Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info
 438 !Edrivers/i2c/i2c-core.c
 439   </chapter>
 440
 441 </book>