Documentation/DocBook/device-drivers.tmpl

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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 !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
 117 X!Edrivers/base/attribute_container.c
 118 -->
 119 !Edrivers/base/dd.c
 120 <!--
 121 X!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
 137 X!Edrivers/acpi/sleep/main.c
 138 X!Edrivers/acpi/sleep/wakeup.c
 139 X!Edrivers/acpi/motherboard.c
 140 X!Edrivers/acpi/bus.c
 141 -->
 142 !Edrivers/acpi/scan.c
 143 !Idrivers/acpi/scan.c
 144 <!-- No correct structured comments
 145 X!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
 151 X!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
 223 X!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>
 278 X!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>
 288 X!Idrivers/video/fbgen.c
 289      </sect1>
 290 KAO -->
 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
 303 X!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 </book>