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