Documentation/DocBook/device-drivers.tmpl

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
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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/time/timer.c
  58      </sect1>
  59      <sect1><title>Wait queues and Wake events</title>
  60 !Iinclude/linux/wait.h
  61 !Ekernel/sched/wait.c
  62      </sect1>
  63      <sect1><title>High-resolution timers</title>
  64 !Iinclude/linux/ktime.h
  65 !Iinclude/linux/hrtimer.h
  66 !Ekernel/time/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/printk.c
  88 !Ekernel/panic.c
  89 !Ekernel/sys.c
  90 !Ekernel/rcu/srcu.c
  91 !Ekernel/rcu/tree.c
  92 !Ekernel/rcu/tree_plugin.h
  93 !Ekernel/rcu/update.c
  94      </sect1>
  95
  96      <sect1><title>Device Resource Management</title>
  97 !Edrivers/base/devres.c
  98      </sect1>
  99
 100   </chapter>
 101
 102   <chapter id="devdrivers">
 103      <title>Device drivers infrastructure</title>
 104      <sect1><title>The Basic Device Driver-Model Structures </title>
 105 !Iinclude/linux/device.h
 106      </sect1>
 107      <sect1><title>Device Drivers Base</title>
 108 !Idrivers/base/init.c
 109 !Edrivers/base/driver.c
 110 !Edrivers/base/core.c
 111 !Edrivers/base/syscore.c
 112 !Edrivers/base/class.c
 113 !Idrivers/base/node.c
 114 !Edrivers/base/firmware_class.c
 115 !Edrivers/base/transport_class.c
 116 <!-- Cannot be included, because
 117      attribute_container_add_class_device_adapter
 118  and attribute_container_classdev_to_container
 119      exceed allowed 44 characters maximum
 120 X!Edrivers/base/attribute_container.c
 121 -->
 122 !Edrivers/base/dd.c
 123 <!--
 124 X!Edrivers/base/interface.c
 125 -->
 126 !Iinclude/linux/platform_device.h
 127 !Edrivers/base/platform.c
 128 !Edrivers/base/bus.c
 129      </sect1>
 130      <sect1><title>Device Drivers DMA Management</title>
 131 !Edrivers/dma-buf/dma-buf.c
 132 !Edrivers/dma-buf/fence.c
 133 !Edrivers/dma-buf/seqno-fence.c
 134 !Iinclude/linux/fence.h
 135 !Iinclude/linux/seqno-fence.h
 136 !Edrivers/dma-buf/reservation.c
 137 !Iinclude/linux/reservation.h
 138 !Edrivers/base/dma-coherent.c
 139 !Edrivers/base/dma-mapping.c
 140      </sect1>
 141      <sect1><title>Device Drivers Power Management</title>
 142 !Edrivers/base/power/main.c
 143      </sect1>
 144      <sect1><title>Device Drivers ACPI Support</title>
 145 <!-- Internal functions only
 146 X!Edrivers/acpi/sleep/main.c
 147 X!Edrivers/acpi/sleep/wakeup.c
 148 X!Edrivers/acpi/motherboard.c
 149 X!Edrivers/acpi/bus.c
 150 -->
 151 !Edrivers/acpi/scan.c
 152 !Idrivers/acpi/scan.c
 153 <!-- No correct structured comments
 154 X!Edrivers/acpi/pci_bind.c
 155 -->
 156      </sect1>
 157      <sect1><title>Device drivers PnP support</title>
 158 !Idrivers/pnp/core.c
 159 <!-- No correct structured comments
 160 X!Edrivers/pnp/system.c
 161  -->
 162 !Edrivers/pnp/card.c
 163 !Idrivers/pnp/driver.c
 164 !Edrivers/pnp/manager.c
 165 !Edrivers/pnp/support.c
 166      </sect1>
 167      <sect1><title>Userspace IO devices</title>
 168 !Edrivers/uio/uio.c
 169 !Iinclude/linux/uio_driver.h
 170      </sect1>
 171   </chapter>
 172
 173   <chapter id="parportdev">
 174      <title>Parallel Port Devices</title>
 175 !Iinclude/linux/parport.h
 176 !Edrivers/parport/ieee1284.c
 177 !Edrivers/parport/share.c
 178 !Idrivers/parport/daisy.c
 179   </chapter>
 180
 181   <chapter id="message_devices">
 182         <title>Message-based devices</title>
 183      <sect1><title>Fusion message devices</title>
 184 !Edrivers/message/fusion/mptbase.c
 185 !Idrivers/message/fusion/mptbase.c
 186 !Edrivers/message/fusion/mptscsih.c
 187 !Idrivers/message/fusion/mptscsih.c
 188 !Idrivers/message/fusion/mptctl.c
 189 !Idrivers/message/fusion/mptspi.c
 190 !Idrivers/message/fusion/mptfc.c
 191 !Idrivers/message/fusion/mptlan.c
 192      </sect1>
 193      <sect1><title>I2O message devices</title>
 194 !Iinclude/linux/i2o.h
 195 !Idrivers/message/i2o/core.h
 196 !Edrivers/message/i2o/iop.c
 197 !Idrivers/message/i2o/iop.c
 198 !Idrivers/message/i2o/config-osm.c
 199 !Edrivers/message/i2o/exec-osm.c
 200 !Idrivers/message/i2o/exec-osm.c
 201 !Idrivers/message/i2o/bus-osm.c
 202 !Edrivers/message/i2o/device.c
 203 !Idrivers/message/i2o/device.c
 204 !Idrivers/message/i2o/driver.c
 205 !Idrivers/message/i2o/pci.c
 206 !Idrivers/message/i2o/i2o_block.c
 207 !Idrivers/message/i2o/i2o_scsi.c
 208 !Idrivers/message/i2o/i2o_proc.c
 209      </sect1>
 210   </chapter>
 211
 212   <chapter id="snddev">
 213      <title>Sound Devices</title>
 214 !Iinclude/sound/core.h
 215 !Esound/sound_core.c
 216 !Iinclude/sound/pcm.h
 217 !Esound/core/pcm.c
 218 !Esound/core/device.c
 219 !Esound/core/info.c
 220 !Esound/core/rawmidi.c
 221 !Esound/core/sound.c
 222 !Esound/core/memory.c
 223 !Esound/core/pcm_memory.c
 224 !Esound/core/init.c
 225 !Esound/core/isadma.c
 226 !Esound/core/control.c
 227 !Esound/core/pcm_lib.c
 228 !Esound/core/hwdep.c
 229 !Esound/core/pcm_native.c
 230 !Esound/core/memalloc.c
 231 <!-- FIXME: Removed for now since no structured comments in source
 232 X!Isound/sound_firmware.c
 233 -->
 234   </chapter>
 235
 236   <chapter id="uart16x50">
 237      <title>16x50 UART Driver</title>
 238 !Edrivers/tty/serial/serial_core.c
 239 !Edrivers/tty/serial/8250/8250_core.c
 240   </chapter>
 241
 242   <chapter id="fbdev">
 243      <title>Frame Buffer Library</title>
 244
 245      <para>
 246        The frame buffer drivers depend heavily on four data structures.
 247        These structures are declared in include/linux/fb.h.  They are
 248        fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs.
 249        The last three can be made available to and from userland.
 250      </para>
 251
 252      <para>
 253        fb_info defines the current state of a particular video card.
 254        Inside fb_info, there exists a fb_ops structure which is a
 255        collection of needed functions to make fbdev and fbcon work.
 256        fb_info is only visible to the kernel.
 257      </para>
 258
 259      <para>
 260        fb_var_screeninfo is used to describe the features of a video card
 261        that are user defined.  With fb_var_screeninfo, things such as
 262        depth and the resolution may be defined.
 263      </para>
 264
 265      <para>
 266        The next structure is fb_fix_screeninfo. This defines the
 267        properties of a card that are created when a mode is set and can't
 268        be changed otherwise.  A good example of this is the start of the
 269        frame buffer memory.  This "locks" the address of the frame buffer
 270        memory, so that it cannot be changed or moved.
 271      </para>
 272
 273      <para>
 274        The last structure is fb_monospecs. In the old API, there was
 275        little importance for fb_monospecs. This allowed for forbidden things
 276        such as setting a mode of 800x600 on a fix frequency monitor. With
 277        the new API, fb_monospecs prevents such things, and if used
 278        correctly, can prevent a monitor from being cooked.  fb_monospecs
 279        will not be useful until kernels 2.5.x.
 280      </para>
 281
 282      <sect1><title>Frame Buffer Memory</title>
 283 !Edrivers/video/fbdev/core/fbmem.c
 284      </sect1>
 285 <!--
 286      <sect1><title>Frame Buffer Console</title>
 287 X!Edrivers/video/console/fbcon.c
 288      </sect1>
 289 -->
 290      <sect1><title>Frame Buffer Colormap</title>
 291 !Edrivers/video/fbdev/core/fbcmap.c
 292      </sect1>
 293 <!-- FIXME:
 294   drivers/video/fbgen.c has no docs, which stuffs up the sgml.  Comment
 295   out until somebody adds docs.  KAO
 296      <sect1><title>Frame Buffer Generic Functions</title>
 297 X!Idrivers/video/fbgen.c
 298      </sect1>
 299 KAO -->
 300      <sect1><title>Frame Buffer Video Mode Database</title>
 301 !Idrivers/video/fbdev/core/modedb.c
 302 !Edrivers/video/fbdev/core/modedb.c
 303      </sect1>
 304      <sect1><title>Frame Buffer Macintosh Video Mode Database</title>
 305 !Edrivers/video/fbdev/macmodes.c
 306      </sect1>
 307      <sect1><title>Frame Buffer Fonts</title>
 308         <para>
 309            Refer to the file lib/fonts/fonts.c for more information.
 310         </para>
 311 <!-- FIXME: Removed for now since no structured comments in source
 312 X!Ilib/fonts/fonts.c
 313 -->
 314      </sect1>
 315   </chapter>
 316
 317   <chapter id="input_subsystem">
 318      <title>Input Subsystem</title>
 319      <sect1><title>Input core</title>
 320 !Iinclude/linux/input.h
 321 !Edrivers/input/input.c
 322 !Edrivers/input/ff-core.c
 323 !Edrivers/input/ff-memless.c
 324      </sect1>
 325      <sect1><title>Multitouch Library</title>
 326 !Iinclude/linux/input/mt.h
 327 !Edrivers/input/input-mt.c
 328      </sect1>
 329      <sect1><title>Polled input devices</title>
 330 !Iinclude/linux/input-polldev.h
 331 !Edrivers/input/input-polldev.c
 332      </sect1>
 333      <sect1><title>Matrix keyboars/keypads</title>
 334 !Iinclude/linux/input/matrix_keypad.h
 335      </sect1>
 336      <sect1><title>Sparse keymap support</title>
 337 !Iinclude/linux/input/sparse-keymap.h
 338 !Edrivers/input/sparse-keymap.c
 339      </sect1>
 340   </chapter>
 341
 342   <chapter id="spi">
 343       <title>Serial Peripheral Interface (SPI)</title>
 344   <para>
 345         SPI is the "Serial Peripheral Interface", widely used with
 346         embedded systems because it is a simple and efficient
 347         interface:  basically a multiplexed shift register.
 348         Its three signal wires hold a clock (SCK, often in the range
 349         of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and
 350         a "Master In, Slave Out" (MISO) data line.
 351         SPI is a full duplex protocol; for each bit shifted out the
 352         MOSI line (one per clock) another is shifted in on the MISO line.
 353         Those bits are assembled into words of various sizes on the
 354         way to and from system memory.
 355         An additional chipselect line is usually active-low (nCS);
 356         four signals are normally used for each peripheral, plus
 357         sometimes an interrupt.
 358   </para>
 359   <para>
 360         The SPI bus facilities listed here provide a generalized
 361         interface to declare SPI busses and devices, manage them
 362         according to the standard Linux driver model, and perform
 363         input/output operations.
 364         At this time, only "master" side interfaces are supported,
 365         where Linux talks to SPI peripherals and does not implement
 366         such a peripheral itself.
 367         (Interfaces to support implementing SPI slaves would
 368         necessarily look different.)
 369   </para>
 370   <para>
 371         The programming interface is structured around two kinds of driver,
 372         and two kinds of device.
 373         A "Controller Driver" abstracts the controller hardware, which may
 374         be as simple as a set of GPIO pins or as complex as a pair of FIFOs
 375         connected to dual DMA engines on the other side of the SPI shift
 376         register (maximizing throughput).  Such drivers bridge between
 377         whatever bus they sit on (often the platform bus) and SPI, and
 378         expose the SPI side of their device as a
 379         <structname>struct spi_master</structname>.
 380         SPI devices are children of that master, represented as a
 381         <structname>struct spi_device</structname> and manufactured from
 382         <structname>struct spi_board_info</structname> descriptors which
 383         are usually provided by board-specific initialization code.
 384         A <structname>struct spi_driver</structname> is called a
 385         "Protocol Driver", and is bound to a spi_device using normal
 386         driver model calls.
 387   </para>
 388   <para>
 389         The I/O model is a set of queued messages.  Protocol drivers
 390         submit one or more <structname>struct spi_message</structname>
 391         objects, which are processed and completed asynchronously.
 392         (There are synchronous wrappers, however.)  Messages are
 393         built from one or more <structname>struct spi_transfer</structname>
 394         objects, each of which wraps a full duplex SPI transfer.
 395         A variety of protocol tweaking options are needed, because
 396         different chips adopt very different policies for how they
 397         use the bits transferred with SPI.
 398   </para>
 399 !Iinclude/linux/spi/spi.h
 400 !Fdrivers/spi/spi.c spi_register_board_info
 401 !Edrivers/spi/spi.c
 402   </chapter>
 403
 404   <chapter id="i2c">
 405      <title>I<superscript>2</superscript>C and SMBus Subsystem</title>
 406
 407      <para>
 408         I<superscript>2</superscript>C (or without fancy typography, "I2C")
 409         is an acronym for the "Inter-IC" bus, a simple bus protocol which is
 410         widely used where low data rate communications suffice.
 411         Since it's also a licensed trademark, some vendors use another
 412         name (such as "Two-Wire Interface", TWI) for the same bus.
 413         I2C only needs two signals (SCL for clock, SDA for data), conserving
 414         board real estate and minimizing signal quality issues.
 415         Most I2C devices use seven bit addresses, and bus speeds of up
 416         to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet
 417         found wide use.
 418         I2C is a multi-master bus; open drain signaling is used to
 419         arbitrate between masters, as well as to handshake and to
 420         synchronize clocks from slower clients.
 421      </para>
 422
 423      <para>
 424         The Linux I2C programming interfaces support only the master
 425         side of bus interactions, not the slave side.
 426         The programming interface is structured around two kinds of driver,
 427         and two kinds of device.
 428         An I2C "Adapter Driver" abstracts the controller hardware; it binds
 429         to a physical device (perhaps a PCI device or platform_device) and
 430         exposes a <structname>struct i2c_adapter</structname> representing
 431         each I2C bus segment it manages.
 432         On each I2C bus segment will be I2C devices represented by a
 433         <structname>struct i2c_client</structname>.  Those devices will
 434         be bound to a <structname>struct i2c_driver</structname>,
 435         which should follow the standard Linux driver model.
 436         (At this writing, a legacy model is more widely used.)
 437         There are functions to perform various I2C protocol operations; at
 438         this writing all such functions are usable only from task context.
 439      </para>
 440
 441      <para>
 442         The System Management Bus (SMBus) is a sibling protocol.  Most SMBus
 443         systems are also I2C conformant.  The electrical constraints are
 444         tighter for SMBus, and it standardizes particular protocol messages
 445         and idioms.  Controllers that support I2C can also support most
 446         SMBus operations, but SMBus controllers don't support all the protocol
 447         options that an I2C controller will.
 448         There are functions to perform various SMBus protocol operations,
 449         either using I2C primitives or by issuing SMBus commands to
 450         i2c_adapter devices which don't support those I2C operations.
 451      </para>
 452
 453 !Iinclude/linux/i2c.h
 454 !Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info
 455 !Edrivers/i2c/i2c-core.c
 456   </chapter>
 457
 458   <chapter id="hsi">
 459      <title>High Speed Synchronous Serial Interface (HSI)</title>
 460
 461      <para>
 462         High Speed Synchronous Serial Interface (HSI) is a
 463         serial interface mainly used for connecting application
 464         engines (APE) with cellular modem engines (CMT) in cellular
 465         handsets.
 466
 467         HSI provides multiplexing for up to 16 logical channels,
 468         low-latency and full duplex communication.
 469      </para>
 470
 471 !Iinclude/linux/hsi/hsi.h
 472 !Edrivers/hsi/hsi.c
 473   </chapter>
 474
 475 </book>