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